Gastro-intestinal haemorrhage risks of selective serotonin receptor antagonist therapy: a new look

Effects of selective serotonin reuptake inhibitors on platelet functions: a literature review

PURPOSE OF REVIEW

Many epidemiological studies have evidenced an increased bleeding risk associated with selective serotonin reuptake inhibitors (SSRIs), yet the underlying mechanisms remain unclear. This review summarizes data on SSRIs' effects on platelet functions assessed with assays used in clinical practice and highlights the areas that deserve further investigation.

RECENT FINDINGS

Conflicting results of SSRI effects on platelet aggregation were observed irrespectively of the agonist used, the antidepressant drug or the study type. Alike, discrepant results were reported with flow-cytometry-based assays assessing either platelet surface glycoprotein levels, integrin activation, agonist-induced secretion of intraplatelet granule content or membrane anionic phospholipid exposure. Other tests may have detected a platelet function defect in SSRIs samples, however, results were largely inconsistent.

SUMMARY

Critical literature examination unveils very low certainty of evidence on potential SSRI effect on platelet functions. Findings are often inconsistent even when similar methods are used, most likely because of differences in study design, included patients (age, comorbid conditions), SSRIs' type and dose, uncontrolled confounding factors, and statistical analysis power. Further studies are needed to disentangle any intrinsic antiplatelet effect of SSRIs and the multiple confounding factors, mainly the depression control itself and the degree of platelet SERT inhibition.

Risk of Gastrointestinal Bleeding with Concurrent Use of NSAID and SSRI: A Systematic Review and Network Meta-Analysis

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used over-the-counter medications that can increase the risk of gastrointestinal (GI) bleeding through antiplatelet effects and loss of GI protection. Selective serotonin reuptake inhibitors (SSRIs), commonly used for mental and behavioral health, are another group of medications that can cause platelet dysfunction. Previous literature has shown a possible increased risk of GI bleeding with concurrent use of SSRIs and NSAIDs. We performed a network meta-analysis comparing NSAIDs, SSRIs, and combined SSRI/NSAIDs to assess the risk of GI bleeding.

METHODS

The following databases were searched: MEDLINE, Embase, Web of Science Core Collection, SciELO, KCI, and Cochrane database. All comparative studies, i.e., case-control, cohort, and randomized controlled trials were included. Direct and network meta-analysis was conducted using DerSimonian-Laird approach and random effect. For binary outcomes, odds ratio (OR) with 95% confidence interval (CI) and p value were calculated.

RESULTS

After a comprehensive search through November 10th, 2021, 15 studies with 82,605 patients were identified. 11 studies reported higher rates of GI bleeds in SSRI/NSAID than SSRI users (36.9% vs 22.8%, OR 2.14, 95% CI 1.52-3.02, p < 0.001, I² = 86.1%). 10 studies compared SSRI/NSAID to NSAID users with higher rates of bleeds in SSRI/NSAID group (40.9% vs 34.2%, OR 1.49, 95% CI 1.20-1.84, p < 0.001, I² = 68.8%). The results were consistent using network meta-analysis as well.

CONCLUSION

Given higher risk of bleeding with concurrent NSAIDs and SSRIs, prescribers should exercise caution when administering NSAIDs and SSRIs concurrently especially in patients with higher risks of GI bleeding.

Interactions between Antidepressants and Warfarin: A Review

Background:

Since warfarin has a very narrow therapeutic index, the interaction between warfarin and antidepressants is very critical and has potentially severe consequences. It is unclear whether clinicians have sufficient knowledge about the risk of bleeding when warfarin and antidepressants are used concomitantly.

Objective:

In this systematic review, we discuss the main considerations when using warfarin with antidepressants.

Methods:

The information about warfarin-antidepressant interactions was obtained from Google Scholar®, PubMed/MEDLINE® and a hand search of the published literature. The following research terms which were systematically combined with each other to find articles: warfarin, anticoagulant, interactions, antidepressant (and each antidepressant name individually), SSRI, SNRI, TCA, MAOI.

Results:

Several possible mechanisms that can cause bleeding when antidepressants and warfarin are used concomitantly, have been discussed. According to the available data, sertraline and citalopram/ escitalopram are safer antidepressants to use with warfarin, whereas fluoxetine and fluvoxamine have a higher interaction potential with warfarin. The remaining antidepressants appear to lie somewhere in between and have little empirical data to guide the clinicians.

Conclusion:

It is recommended that when an antidepressant is prescribed to a patient using warfarin, patient’s international normalized ratio (INR) level should be checked regularly. In this review, the interaction between warfarin and antidepressants, including new ones, were evaluated inclusively and in detail.

Assessment of incidence, causality, severity, and preventability of suspected adverse drug reactions to antidepressant medications in a psychiatry outpatient setting of a secondary care hospital

Background:

Antidepressant medications are primarily used in the management of depression and various anxiety disorders. Antidepressant medications are known to cause adverse drug reactions (ADRs). Reporting ADRs can help in the rational use of medication and better patient drug management.

Objective:

The aim of this study was to monitor the incidence and nature of ADRs to antidepressant medications in a psychiatric outpatient setting of a secondary care hospital of the UAE.

Materials and Methods:

It was a cross-sectional study conducted in the psychiatric outpatient setting of a secondary care hospital. Patients attending psychiatry outpatient department and prescribed with antidepressant medications were included. All clinical side effects or ADRs noted by physician and reported by patients were documented and assessed according to causality, severity, and preventability scales.

Results:

A total of 131 patients were screened for the presence or occurrence of ADRs. During the study duration, an aggregate of 29 patients reported at least one ADR. Incidence of suspected ADR to antidepressant medications was found to be 22.1%. Most commonly documented suspected ADR was found to be weight gain in eight (18.1%) patients followed by somnolence in four (9.1%) patients. Escitalopram was the most common drug implicated with ADR in 13 (29.6%) patients followed by fluoxetine in 6 (13.6%) patients. According to World Health Organization-The Uppsala Monitoring Centre causality assessment, the predominance of the suspected ADRs was of “possible” type in 27 (61%) patients, and “mild” in severity in 40 (91%) patients, and “not preventable” in 37 (84%) patients. A statistically significant association (P = 0.019) was observed only between the presence of drug-interaction and the occurrence of ADR (relative risk: 0.429, confidence interval: 0.211–0.872).

Conclusion:

Most of the suspected ADRs related to antidepressants were “mild,” “predictable,” and “not preventable” in nature. Continuous monitoring may help in identifying, reducing, and preventing the risk of ADRs.

Clinically relevant drug interactions between newer antidepressants and oral anticoagulants

Introduction: This is a review of the drug interactions (DIs) between newer antidepressants and oral anticoagulants (OACs): vitamin K antagonists (VKAs) and direct-acting OACs (DOACs).Areas covered: Articles were obtained from PubMed searches performed for each of the newer antidepressants and oral anticoagulants. The basic pharmacokinetic and pharmacodynamic mechanisms for DIs with these drugs were summarized. Some newer antidepressants are inhibitors of a number of cytochrome P450 (CYP) isoforms and many antidepressants appear to have potential to impair serotonin platelet function and increase bleeding risk.Expert opinion: Clinicians should not forget that the DIs between newer antidepressants and VKAs can be potentially lethal. Among SSRIs, fluoxetine and fluvoxamine appear to be associated with the highest DI risk with warfarin, the most commonly prescribed VKA worldwide. Case reports featuring duloxetine, mirtazapine and trazadone suggested potential for interaction with warfarin. As CYP3A4 is an important metabolic pathway for all DOACs except dabigatran, it appears reasonable to recommend avoiding the co-prescription of fluoxetine and fluvoxamine (weak to moderate CYP3A4 inhibitors) and St John's wort (CYP3A4 inducer). Many package inserts for the newer antidepressants include a warning regarding an increased risk of bleeding events with concomitant use of these agents with OACs.

SSRI/SNRI Therapy is Associated With a Higher Risk of Gastrointestinal Bleeding in LVAD Patients

BACKGROUND

Gastrointestinal bleeding (GIB) is common in left ventricular assist device (LVAD) patients. Serotonin release from platelets promotes platelet aggregation, and selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitor (SSRI/SNRI) therapy inhibits the transporter responsible for re-uptake.

METHODS

We reviewed the records of LVAD (HeartMateII™, Abbott Medical, Lake Bluff, IL, USA and Heartware™, Medtronic, Minneapolis, MN, USA) patients at the Medical University of South Carolina and Johns Hopkins Hospital between January 2009 and January 2016. After exclusions, 248 patients were included for analysis. After univariate analysis, logistic regression multivariate analysis was performed to adjust for any demographic, cardiovascular, and laboratory data variables found to be associated with GI bleeding post-LVAD.

RESULTS

Gastrointestinal bleeding occurred in 85 patients (35%) with 55% of GIBs due to arteriovenous malformations (AVMs). Of the total cohort, 105 patients received an SSRI or SNRI during LVAD support. Forty-four (44) SSRI/SNRI (41.9%) and 41 non-SSRI/SNRI (28.7%) patients had a GIB (RR 1.46, p = 0.03). Twenty-six (26) (24.8%) of the SSRI/SNRI patients had a GIB due to AVMs versus 21 (14.7%) of the non-SSRI/SNRI patients (RR 1.69, p = 0.05). In fully-adjusted multivariate regression analysis, SSRI/SNRI therapy was independently associated with GIB (OR 1.78, p = 0.045). For GIB, the number needed to harm (NNH) was 7.6.

CONCLUSION

In conclusion, SSRI/SNRI therapy is independently associated with an increased risk of GIB in LVAD patients.

SSRI co-medication with NOAC or VKA does not increase hospitalisation for bleeding: A retrospective nationwide cohort study in Austria 2010-2015

OBJECTIVES

Non-vitamin K oral anticoagulants (NOACs) or vitamin K antagonists (VKAs) are used for the prophylaxis and treatment of thromboembolic events. A potential drug-drug interaction and increased bleeding events have been reported with co-medication of selective serotonin receptor inhibitors (SSRIs) and VKA. The aim of this study was to investigate the bleeding risk of a coprescription of NOAC or VKA with SSRI.

METHODS

Patients with prescription of NOAC or VKA and an antidepressant drug therapy (ADTx) were selected from the drug reimbursement database of 13 Austrian health insurance funds. For this cohort, hospital discharge diagnoses for gastrointestinal bleeding, cerebral haemorrhage, and bleeding anaemia between 2010 and 2015 were analysed.

RESULTS

Data were available from 50 196 female and 31 308 male patients. Among these, 892 patients had 987 hospitalisations with bleeding events. The most frequent bleeding cases were gastrointestinal bleedings with 588 events (59.6%), followed by cerebral haemorrhage with 344 (34.8%), and bleeding anaemia with 55 events (5.6%), respectively. The risk of bleeding events was similar between SSRI and other ADTx, when combined with oral anticoagulants (p = 0.51). Concomitant treatment of patients with SSRI or other ADTx and NOAC was associated with an increased bleeding risk compared with cotreatment with VKA (1.21, 95% CI: 1.05-1.40; p = 0.0097).

CONCLUSION

Co-medication of SSRI with VKA or NOAC has little if any impact on hospital discharge diagnoses for bleeding events compared with cotreatment of those anticoagulants with other antidepressant medications.

Two novel, putative mechanisms of action for citalopram-induced platelet inhibition

Citalopram, a selective serotonin reuptake inhibitor (SSRI), inhibits platelet function in vitro. We have previously shown that this action is independent of citalopram's ability to block serotonin uptake by the serotonin transporter and must therefore be mediated via distinct pharmacological mechanisms. We now report evidence for two novel and putative mechanisms of citalopram-induced platelet inhibition. Firstly, in platelets, citalopram blocked U46619-induced Rap1 activation and subsequent platelet aggregation, but failed to inhibit U46619-induced increases in cytosolic Ca²⁺. Similarly, in neutrophils, citalopram inhibited Rap1 activation and downstream functions but failed to block PAF-induced Ca²⁺ mobilisation. In a cell-free system, citalopram also reduced CalDAG-GEFI-mediated nucleotide exchange on Rap1B. Secondly, the binding of anti-GPVI antibodies to resting platelets was inhibited by citalopram. Furthermore, citalopram-induced inhibition of GPVI-mediated platelet aggregation was instantaneous, reversible and displayed competitive characteristics, suggesting that these effects were not caused by a reduction in GPVI surface expression, but by simple competitive binding. In conclusion, we propose two novel, putative and distinct inhibitory mechanisms of action for citalopram: (1) inhibition of CalDAG-GEFI/Rap1 signalling, and (2) competitive antagonism of GPVI in platelets. These findings may aid in the development of novel inhibitors of CalDAG-GEFI/Rap1-dependent nucleotide exchange and novel GPVI antagonists.

Gastrointestinal bleeding risk of selective serotonin reuptake inhibitors by level of kidney function: A population-based cohort study

Aim

To estimate the risk of gastrointestinal (GI) bleeding associated with serotonin reuptake inhibitors (SSRIs) by level of kidney function.

Methods

We conducted a cohort study using the Clinical Practice Research Datalink linked to Hospital Episode Statistics. We identified patients with chronic kidney disease (CKD; estimated glomerular filtration rate <60 ml min^–1 1.73 m^–2 for ≥3 months), and a comparison group of patients without it. Patients with CKD were further classified as stage 3a (eGFR 45–59 ml min^–1 1.73 m^–2), 3b (30–44 ml min^–1 1.73 m^–2) and 4/5 (<30 ml min^–1 1.73 m^–2). We excluded prevalent SSRI users at cohort entry. Exposure was time‐dependent SSRI prescription and outcome was first hospitalization for GI bleeding. We estimated adjusted rate ratio (aRR) and rate difference (aRD) of GI bleeding comparing periods with and without SSRI prescription at each level of kidney function.

Results

The aRRs and aRDs were: (i) no CKD (n = 202 121) aRR: 1.66 (95%CI 1.37–2.01), aRD: 2.0/1000 person–years (5.5 vs. 3.5/1000 person–years in period with and without SSRIs); (ii) CKD stage 3a (n = 153 316) aRR: 1.86 (1.62–2.15), aRD: 4.2/1000 person–years (8.3 vs. 4.1/1000 person–years); (iii) CKD stage 3b (n = 46 482) aRR: 1.61 (1.27–2.04), aRD: 4.8/1000 person–years (9.9 vs. 5.1/1000 person–years); and (iv) CKD stage 4/5 (n = 11 197) aRR: 1.84 (1.14–2.96), aRD: 7.9/1000 person–years (15.3 vs. 7.4/1000 person–years). While there was no evidence of increase in the aRR (P = 0.922), there was strong evidence that the aRD increased as kidney function deteriorated (P = 0.001).

Conclusions

While the relative risk was constant, the excess risk of GI bleeding associated with SSRIs markedly increased among patients with decreased kidney function.

Toxicological Assessment of Venlafaxine: Acute and Subchronic Toxicity Study in Rats

Antidepressants are the most commonly prescribed drugs for psychiatric treatment, and venlafaxine (VEN) is one of the most popular options. Venlafaxine is a nontricyclic dual-acting serotonin-norepinephrine reuptake inhibitor. Although an increased incidence of acute toxicity and addiction has been reported, controlled studies examining its toxic effects on different organs are still lacking. This study investigated the possible toxic effects of VEN on the liver, kidney, and gastric tissues. Three groups of rats were administered saline, a single LD₅₀ dose (350 mg/kg), or 100 mg/kg VEN daily, followed by increases in the dose of 50 mg/kg every 10 days for 30 days (about 10 times the therapeutic doses). The following parameters of liver and kidney injury were then assayed: alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, prothrombin time, partial thromboplastin time, blood urea nitrogen, and serum creatinine. A histopathological examination was then conducted. Both acute and subchronic administration of VEN produced multiple clinical manifestations in the experimental animals, including seizures, coma, and even death. Moreover, the liver and renal function tests indicated injury in these tissues. Furthermore, the histopathological examination showed signs of organ toxicity after both acute and chronic VEN exposure. This study has shown that VEN has harmful effects on the liver, kidney, and stomach in either a single high dose (LD₅₀) or repeated exposure to 10 times the therapeutic doses. As a result, strategies to increase awareness of these effects among physicians and the public are needed because this drug may be addictive.

Addressing the Side Effects of Contemporary Antidepressant Drugs: A Comprehensive Review

Randomized trials have shown that selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) have better safety profiles than classical tricyclic antidepressants (TCAs). However, an increasing number of studies, including meta-analyses, naturalistic studies, and longer-term studies suggested that SSRIs and SNRIs are no less safe than TCAs. We focused on comparing the common side effects of TCAs with those of newer generation antidepressants including SSRIs, SNRIs, mirtazapine, and bupropion. The main purpose was to investigate safety profile differences among drug classes rather than the individual antidepressants, so studies containing comparison data on drug groups were prioritized. In terms of safety after overdose, the common belief on newer generation antidepressants having fewer side effects than TCAs appears to be true. TCAs were also associated with higher drop-out rates, lower tolerability, and higher cardiac side-effects. However, evidence regarding side effects including dry mouth, gastrointestinal side effects, hepatotoxicity, seizure, and weight has been inconsistent, some studies demonstrated the superiority of SSRIs and SNRIs over TCAs, while others found the opposite. Some other side effects such as sexual dysfunction, bleeding, and hyponatremia were more prominent with either SSRIs or SNRIs.

Antidepressant use and risk of adverse outcomes in people aged 20-64 years: cohort study using a primary care database

BACKGROUND

Antidepressants are one of the most commonly prescribed medications in young and middle-aged adults, but there is relatively little information on their safety across a range of adverse outcomes in this age group. This study aimed to assess associations between antidepressant treatment and several adverse outcomes in people aged 20-64 years diagnosed with depression.

METHODS

We conducted a cohort study in 238,963 patients aged 20-64 years registered with practices across the UK contributing to the QResearch primary care database. Only patients with a first diagnosis of depression were included. Outcomes were falls, fractures, upper gastrointestinal bleed, road traffic accidents, adverse drug reactions and all-cause mortality recorded during follow-up. Cox proportional hazards models were used to estimate hazard ratios associated with antidepressant exposure adjusting for potential confounding variables.

RESULTS

During 5 years of follow-up, 4651 patients had experienced a fall, 4796 had fractures, 1066 had upper gastrointestinal bleeds, 3690 had road traffic accidents, 1058 had experienced adverse drug reactions, and 3181 patients died. Fracture rates were significantly increased for selective serotonin reuptake inhibitors (adjusted hazard ratio 1.30, 95% CI 1.21-1.39) and other antidepressants (1.28, 1.11-1.48) compared with periods when antidepressants were not used. All antidepressant drug classes were associated with significantly increased rates of falls. Rates of adverse drug reactions were significantly higher for tricyclic and related antidepressants (1.54, 1.25-1.88) and other antidepressants (1.61, 1.22-2.12) compared with selective serotonin reuptake inhibitors. Trazodone was associated with a significantly increased risk of upper gastrointestinal bleed. All-cause mortality rates were significantly higher for tricyclic and related antidepressants (1.39, 1.22-1.59) and other antidepressants (1.26, 1.08-1.47) than for selective serotonin reuptake inhibitors over 5 years but not 1 year, and were significantly reduced after 85 or more days of treatment with selective serotonin reuptake inhibitors. Mirtazapine was associated with significantly increased mortality rates over 1 and 5 years of follow-up.

CONCLUSIONS

Selective serotonin reuptake inhibitors had higher rates of fracture than tricyclic and related antidepressants but lower mortality and adverse drug reaction rates than the other antidepressant drug classes. The association between mirtazapine and increased mortality merits further investigation. These risks should be carefully considered and balanced against potential benefits for individual patients when the decision to prescribe an antidepressant is made.

Use of beta-blockers and risk of serious upper gastrointestinal bleeding: a population-based case-control study

BACKGROUND

Some studies indicate a reduced risk of serious upper gastrointestinal bleeding (UGIB) for users of beta-blockers, but the association remains to be confirmed in larger studies and characterized with respect to differences among beta-blockers. We aimed to assess whether beta-blocker use decreases the risk of UGIB.

METHODS

We conducted a register-based, population-based case-control study in Denmark. We identified cases with a first validated discharge diagnosis of UGIB during the period 1995-2006. Controls were selected by risk-set sampling in a ratio of 10:1. We estimated crude and adjusted odds ratios (ORs) of the association between current beta-blocker use and the risk of UGIB by using conditional logistic regression and further stratified by selective and non-selective beta-blockers, respectively.

RESULTS

We identified 3571 UGIB cases and 35,582 controls. Use of beta-blockers was not found to be associated with a decreased risk of UGIB (adjusted OR 1.10; 95% CI: 1.00-1.21). The association remained neutral after stratification by selective and non-selective beta-blockers, and by single beta-blocker substances. Similarly, we found no association between current beta-blocker use and the risk of UGIB within different subgroups.

CONCLUSIONS

We found no association between beta-blocker use and UGIB.

Serotonin Reuptake Inhibitors and Risk of Abnormal Bleeding

Serotonin reuptake inhibitors (SRIs) increase the risk of abnormal bleeding by lowering platelet serotonin and hence the efficiency of platelet-driven hemostasis; by increasing gastric acidity and possibly gastric ulceration; and by other mechanisms. The upper gastrointestinal tract is the commonest site of SRI-related abnormal bleeding; bleeding at this location may be increased by concurrent nonsteroidal anti-inflammatory drug therapy and by treatment with antiplatelet or anticoagulant drugs. Bleeding at this location may be reduced by concurrent administration of acid-suppressing drugs.

Bleeding risk under selective serotonin reuptake inhibitor (SSRI) antidepressants: A meta-analysis of observational studies

Selective serotonin reuptake inhibitors (SSRIs) have been reported to be potentially associated with an increased risk of bleeding. A meta-analysis of observational studies was conducted to quantify this risk. Case-control and cohort studies investigating bleeding risk under SSRI therapy were retrieved by searching the Medline, Pascal, Google Scholar and Scopus databases. Case-control studies were included if they reported bleeding incidents with and without the use of SSRIs and cohort studies were included if they reported the rate of bleeds among SSRI users and non-users. The main outcome was severe bleeding, whatever the site. Only data concerning SSRI belonging to the ATC class N06AB were used. For both case-control and cohort studies, we recorded the adjusted effect estimates and their 95% confidence intervals (CI). Pooled adjusted odds ratio (OR) estimates were computed for case-control and cohort studies using an inverse-variance model. Meta-analysis of the adjusted ORs of 42 observational studies showed a significant association between SSRI use and the risk of bleeding [OR 1.41 (95% CI 1.27-1.57), random effect model, p<0.0001]. The association was found for the 31 case-control studies (1,255,073 patients), with an increased risk of 41% of bleeding [OR 1.41 (95% CI 1.25-1.60)], as well as for the 11 cohort studies including 187,956 patients [OR 1.36 (95% CI 1.12-1.64)]. Subgroup analyses showed that the association remained constant whatever the characteristics of studies. This meta-analysis shows an increased risk of bleeding of at least 36% (from 12% to 64%) based on the high-level of observational studies with SSRIs use.

Severe potential drug-drug interactions in older adults with dementia and associated factors

OBJECTIVE

To identify the main severe potential drug-drug interactions in older adults with dementia and to examine the factors associated with these interactions.

METHOD

This was a cross-sectional study. The enrolled patients were selected from six geriatrics clinics of tertiary care hospitals across Mexico City. The patients had received a clinical diagnosis of dementia based on the current standards and were further divided into the following two groups: those with severe drug-drug interactions (contraindicated/severe) (n=64) and those with non-severe drug-drug interactions (moderate/minor/absent) (n=117). Additional socio-demographic, clinical and caregiver data were included. Potential drug-drug interactions were identified using Micromedex Drug Reax 2.0® database.

RESULTS

A total of 181 patients were enrolled, including 57 men (31.5%) and 124 women (68.5%) with a mean age of 80.11±8.28 years. One hundred and seven (59.1%) patients in our population had potential drug-drug interactions, of which 64 (59.81%) were severe/contraindicated. The main severe potential drug-drug interactions were caused by the combinations citalopram/anti-platelet (11.6%), clopidogrel/omeprazole (6.1%), and clopidogrel/aspirin (5.5%). Depression, the use of a higher number of medications, dementia severity and caregiver burden were the most significant factors associated with severe potential drug-drug interactions.

CONCLUSIONS

Older people with dementia experience many severe potential drug-drug interactions. Anti-depressants, antiplatelets, anti-psychotics and omeprazole were the drugs most commonly involved in these interactions. Despite their frequent use, anti-dementia drugs were not involved in severe potential drug-drug interactions. The number and type of medications taken, dementia severity and depression in patients in addition to caregiver burden should be considered to avoid possible drug interactions in this population.

Use of SSRI, But Not SNRI, Increased Upper and Lower Gastrointestinal Bleeding: A Nationwide Population-Based Cohort Study in Taiwan

Selective serotonin receptor inhibitor (SSRI) and serotonin-noradrenaline reuptake inhibitor (SNRI) users have been reported to have an increased risk of upper gastrointestinal bleeding (UGIB), but their association with lower gastrointestinal bleeding (LGIB) is less studied. This study aimed to analyze the incidence of UGIB and LGIB among SSRI users, SNRI users, and controls.Using the National Health Insurance Research Database of Taiwan, 9753 subjects who were taking serotonin reuptake inhibitors (8809 with SSRIs, and 944 with SNRIs), and 39,012 age, sex, and enrollment time-matched controls were enrolled at a 1:4 ratio. The log-rank test was used to analyze differences in the cumulative hazard of UGIB and LGIB between groups. Cox proportional hazard regression analysis was used to evaluate the independent risk factors for UGIB and LGIB.During the 10-year follow-up period from 2000 to 2010, SSRI users, but not SNRI users, had significantly higher incidences of UGIB and LGIB than the controls (P < 0.001; log-rank test). The use of SSRIs, but not SNRIs, was independently associated with an increased risk of UGIB (hazard ratio [HR]:1.97; 95% confidence interval [CI]: 1.67-2.31) and LGIB (HR: 2.96, 95% CI: 2.46-3.57) after adjusting for age, sex, underlying comorbidities, and medications.The long-term use of SSRIs significantly increased the risk of UGIB and LGIB, and caused more LGIB than UGIB in the general population after adjusting for possible confounding factors, but the association between SNRIs and GIB is insignificant. Further prospective studies are needed to clarify this important issue.

Differential impact of selective serotonin reuptake inhibitors on platelet response to clopidogrel: a randomized, double-blind, crossover trial

STUDY OBJECTIVE

To assess the effect of two selective serotonin reuptake inhibitors (SSRIs), fluvoxamine and citalopram, that markedly differ in their level of cytochrome P450 (CYP) 2C19 inhibition, on the laboratory response to clopidogrel, a prodrug requiring metabolism by the CYP system, and especially CYP2C19, to produce its active form.

DESIGN

Randomized, double-blind, crossover trial.

SETTING

Clinical research unit of an academic medical center.

SUBJECTS

Fifteen healthy male volunteers.

INTERVENTION

All subjects received clopidogrel as a 300-mg loading dose on day 1, followed by 75 mg/day on days 2 and 3. Platelet function was tested at baseline and then after clopidogrel treatment on day 3. After a washout period of 2 weeks, subjects were randomly assigned in a double-blind manner to receive either citalopram 20 mg/day or fluvoxamine 100 mg/day for 7 days. On day 5, platelet function was tested while receiving the SSRI treatment alone; then, a 300-mg clopidogrel loading dose was administered, followed by clopidogrel 75 mg/day on days 6 and 7. Platelet function was then reassessed on day 7 while receiving the combination of the SSRI and clopidogrel. The treatment protocol was then repeated after a washout period of 2 weeks in all subjects with the other SSRI.

MEASUREMENTS AND MAIN RESULTS

The antiplatelet effects of fluvoxamine and citalopram and their interactions with clopidogrel were assessed. The response to these three drugs was assessed by light transmittance aggregometry and vasodilator-stimulated phosphoprotein phosphorylation, reporting P2Y12 receptor reactivity. Both fluvoxamine and citalopram tended to reduce adenosine diphosphate-induced aggregation: 80.8 ± 3.4% at baseline, 67.3 ± 6.3% while receiving citalopram, and 65.8 ± 6.4% while receiving fluvoxamine. All subjects had a good laboratory response to clopidogrel, with a mean aggregation of 23.5 ± 3.2% and a mean platelet reactivity index of 47.7 ± 3.9% (p<0.001 compared with baseline for both methods). Laboratory response to clopidogrel was significantly attenuated in the presence of fluvoxamine compared with the response in the presence of citalopram as tested both by aggregometry (32.3 ± 4.2% vs 23.4 ± 3%, p=0.04) and by vasodilator-stimulated phosphoprotein phosphorylation (52.7 ± 5.1% vs 35.9 ± 4.2%, p=0.02).

CONCLUSION

Fluvoxamine attenuated the laboratory response to clopidogrel, possibly through inhibition of CYP2C19, whereas citalopram did not affect this response. These potential drug interactions should be taken into consideration in the selection of the appropriate antidepressant agent for patients who are treated with clopidogrel.

Sertraline-induced periorbital purpura: a case report

OBJECTIVE

The incidence of mild to severe levels of spontaneous bleeding due to the usage of selective serotonin reuptake inhibitors (SSRIs) is relatively low. Although the exact mechanism is not known, it is thought that inhibition of the serotonin transporter together with a decrease in platelet serotonin could be responsible for the bleeding. Therefore, the use of SSRIs in conjunction with anti-aggregants may predispose to or exacerbate the risk of bleeding. In this case report, we describe a 44-year-old female patient with a diagnosis of anxiety disorder who spontaneously developed periorbital purpura during treatment with sertraline.

CONCLUSION

Abnormal bleeding after treatment with an SSRI should be kept in mind, and alternative non-SSRI drugs of choice in such cases would be more appropriate. More extensive and comprehensive studies focusing on hemostasis and bleeding disorders are needed for SSRIs such as sertraline.

Use of selective serotonin reuptake inhibitors and risk of upper gastrointestinal bleeding: a systematic review and meta-analysis

BACKGROUND & AIMS

Selective serotonin reuptake inhibitors (SSRIs) are used to treat various psychiatric disorders. However, there are concerns that SSRIs increase the risk for upper gastrointestinal bleeding (UGIB).

METHODS

We performed a systematic review and meta-analysis of controlled observational studies to determine whether SSRI use affects the risk for UGIB. Our analysis included all observational studies that compared UGIB development among patients receiving SSRIs vs no treatment. We calculated pooled odds ratios using random- and fixed-effects models.

RESULTS

A total of 22 studies (6 cohort and 16 case-control studies) involving more than 1,073,000 individuals were included in our meta-analysis. In comparing SSRI users with patients who had not taken SSRIs, the odds for developing UGIB were 1.55-fold higher (odds ratio, 1.55; 95% confidence interval, 1.35-1.78). In subgroup analyses, the association was greatest for patients who received concurrent therapy with nonsteroidal anti-inflammatory or antiplatelet drugs; we found no significant increase in the risk of developing UGIB among patients receiving concurrent acid-suppressing drugs.

CONCLUSIONS

SSRI use was associated with an almost 2-fold increase in the risk of developing UGIB, especially among patients at high risk for GI bleeding (concurrent use of nonsteroidal anti-inflammatory or antiplatelet drugs). This risk might be reduced significantly by concomitant use of acid-suppressing drugs.

Defining a reference set to support methodological research in drug safety

BACKGROUND

Methodological research to evaluate the performance of methods requires a benchmark to serve as a referent comparison. In drug safety, the performance of analyses of spontaneous adverse event reporting databases and observational healthcare data, such as administrative claims and electronic health records, has been limited by the lack of such standards.

OBJECTIVES

To establish a reference set of test cases that contain both positive and negative controls, which can serve the basis for methodological research in evaluating methods performance in identifying drug safety issues.

RESEARCH DESIGN

Systematic literature review and natural language processing of structured product labeling was performed to identify evidence to support the classification of drugs as either positive controls or negative controls for four outcomes: acute liver injury, acute kidney injury, acute myocardial infarction, and upper gastrointestinal bleeding.

RESULTS

Three-hundred and ninety-nine test cases comprised of 165 positive controls and 234 negative controls were identified across the four outcomes. The majority of positive controls for acute kidney injury and upper gastrointestinal bleeding were supported by randomized clinical trial evidence, while the majority of positive controls for acute liver injury and acute myocardial infarction were only supported based on published case reports. Literature estimates for the positive controls shows substantial variability that limits the ability to establish a reference set with known effect sizes.

CONCLUSIONS

A reference set of test cases can be established to facilitate methodological research in drug safety. Creating a sufficient sample of drug-outcome pairs with binary classification of having no effect (negative controls) or having an increased effect (positive controls) is possible and can enable estimation of predictive accuracy through discrimination. Since the magnitude of the positive effects cannot be reliably obtained and the quality of evidence may vary across outcomes, assumptions are required to use the test cases in real data for purposes of measuring bias, mean squared error, or coverage probability.

Risk of upper gastrointestinal bleeding with selective serotonin reuptake inhibitors with or without concurrent nonsteroidal anti-inflammatory use: a systematic review and meta-analysis

OBJECTIVES

There is emerging concern that selective serotonin reuptake inhibitors (SSRIs) may be associated with an increased risk of upper gastrointestinal (GI) bleeding, and that this risk may be further increased by concurrent use of nonsteroidal anti-inflammatory (NSAID) medications. Previous reviews of a relatively small number of studies have reported a substantial risk of upper GI bleeding with SSRIs; however, more recent studies have produced variable results. The objective of this study was to obtain a more precise estimate of the risk of upper GI bleeding with SSRIs, with or without concurrent NSAID use.

METHODS

MEDLINE, EMBASE, PsycINFO, the Cochrane central register of controlled trials (through April 2013), and US and European conference proceedings were searched. Controlled trials, cohort, case-control, and cross-sectional studies that reported the incidence of upper GI bleeding in adults on SSRIs with or without concurrent NSAID use, compared with placebo or no treatment were included. Data were extracted independently by two authors. Dichotomous data were pooled to obtain odds ratio (OR) of the risk of upper GI bleeding with SSRIs +/- NSAID, with a 95% confidence interval (CI). The main outcome and measure of the study was the risk of upper GI bleeding with SSRIs compared with placebo or no treatment.

RESULTS

Fifteen case-control studies (including 393,268 participants) and four cohort studies were included in the analysis. There was an increased risk of upper GI bleeding with SSRI medications in the case-control studies (OR=1.66, 95% CI=1.44,1.92) and cohort studies (OR=1.68, 95% CI=1.13,2.50). The number needed to harm for upper GI bleeding with SSRI treatment in a low-risk population was 3,177, and in a high-risk population it was 881. The risk of upper GI bleeding was further increased with the use of both SSRI and NSAID medications (OR=4.25, 95% CI=2.82,6.42).

CONCLUSIONS

SSRI medications are associated with a modest increase in the risk of upper GI bleeding, which is lower than has previously been estimated. This risk is significantly elevated when SSRI medications are used in combination with NSAIDs, and physicians prescribing these medications together should exercise caution and discuss this risk with patients.

Psychiatric comorbidity in the treatment of patients with inflammatory bowel disease

Ulcerative colitis and Crohn’s disease, commonly known as inflammatory bowel disease (IBD), draw attention from specialists of various disorders, including gastroenterology, psychiatry, and radiology. The involvement of a cortical influence in the brain-gut axis as well as the interaction of the hypothalamic-pituitary-adrenal axis and the peripheral nervous system provide an initial explanation of the psychological symptoms associated with IBD. The involvement of structures the limbic system, such as the anterior cingulate cortex, the prefrontal cortex, and the amygdala, paves the way for the discovery of the mechanisms underlying depression depression, anxiety, alexithymia, personality traits, and other psychological impairments following the onset of IBD. Psychiatric therapy in IBD patients is almost as important as the gastroenterological approach and consists of pharmacological treatment and psychotherapy. Neither of the available psychiatric treatment methods is considered the golden standard because both methods have side effects, and psychotropic medication can provoke the worsening of IBD symptoms. Thus, both approaches must be applied with awareness of the possibility of side effects. We suggest that psychiatrists and gastroenterologists work together to reach a consensus on IBD therapy to ensure success and to reduce side effects and relapse to the lowest possible rates.

Serotonin reuptake inhibitors and bleeding risks in major orthopedic procedures

BACKGROUND

Risk of abnormal bleeding in surgery patients prescribed serotonin reuptake inhibitors (SRIs) is unclear. Considering the quantity of literature on abnormal gastrointestinal (GI) bleeding with SRIs, relatively little exists on SRI bleeding risks in surgical procedures. We investigated whether SRIs increase the risk of surgical bleeding in patients undergoing knee and hip total joint replacement.

METHODS

RA retrospective case-control study was conducted among subjects undergoing primary total hip and knee replacement surgeries from January 2005 to March 2011 at a single institution. The experimental group was defined by utilization of SRIs at the time of surgery (the independent variable). The control group was matched for age, sex, ethnicity, and type of surgery (hip or knee). Any case with preoperative hematocrit <30, platelets <100,000; abnormal prothrombin time, partial-prothrombin time, and international normalized ratio (INR), primary bleeding disorder, medical conditions, or medications associated with increased bleeding was excluded. All cases were randomly selected.

RESULTS

RA total of 194 subjects (hip 104, knee 90) were included. Statistical analysis was performed on the SRI group (n = 71) and the control, non-SRI group (n = 123). No difference was found between the groups in estimated blood loss, hemoglobin, hematocrit, platelets, PT, PTT, and INR from preoperative to postoperative day 1, 2, and 3. Furthermore, no subjects in either group required blood transfusions.

CONCLUSION

SRIs were not associated with increased risk of bleeding in primary knee or hip replacement surgeries in this study. The hypothesis that SRIs increase the risk of bleeding based on presumptions about their action on platelet aggregation is uncertain and warrants further study.

Bleeding complications and liver injuries during phenprocoumon treatment: a multicentre prospective observational study in internal medicine departments

BACKGROUND

Even after the recent approval of newer oral anticoagulants for clinical use, the vitamin K antagonist phenprocoumon remains an important treatment option for many patients. In order to quantify the hitherto "accepted" risks of phenprocoumon treatment, we analyzed adverse drug reactions (ADRs) that led to hospitalization on the internal medicine wards of four German pharmacovigilance centers.

METHODS

We prospectively analyzed ADRs leading to hospitalization on the internal medicine wards of the hospitals belonging to the German Network of Regional Pharmacovigilance Centers (Rostock, Greifswald, Jena, and the Sophien- und Hufeland-Klinikum in Weimar) in the years 2000 to 2008.

RESULTS

The 851 patients hospitalized for a phenprocoumon-associated ADR accounted for 12.4% of the 6887 ADR-related hospitalizations in the period of the study. 723 (85%) were admitted for a hemorrhage, usually in the gastrointestinal tract (482 patients); 8 patients died as a consequence of hemorrhage associated with phenprocoumon exposure. Using drug utilization data for the catchment areas of the participating hospitals, we calculate a rate of 5 to 7 hemorrhages leading to hospitalization in an internal medicine ward per 1000 patient-years under phenprocoumon treatment. One-third of the patients who had a hemorrhage were taking other interacting drugs, mainly inhibitors of platelet aggregation and non-steroidal anti-inflammatory drugs. Among the patients who were taking phenprocoumon because of a history of thromboembolic events or for atrial fibrillation, 60% to 70% of those who had hemorrhages had an international normalized ratio (INR) that was above the upper limit of the therapeutic range. Phenprocoumon-associated impairment of liver function arose in 23 patients (2.7%).

CONCLUSION

In this study, about one-eighth of all ADR-related admissions to hospital internal medicine wards were associated with phenprocoumon. There is a need for a comparative risk-benefit assessment of phenprocoumon and the newer oral anticoagulants under real-life conditions.

[Integral Care Guide for Early Detection and Diagnosis of Depressive Episodes and Recurrent Depressive Disorder in Adults. Integral Attention of Adults with a Diagnosis of Depressive Episodes and Recurrent Depressive Disorder: Part II: General Aspects of Treatment, Management of the Acute Phase, Continuation and Maintenance of Patients with a Depression Diagnosis]

INTRODUCTION

This article presents recommendations based on evidence gathered to answer a series of clinical questions concerning the depressive episode and the recurrent depressive disorder, with emphasis on general treatment aspects, treatment in the acute phase and management of the continuation/maintenance, all intended to grant health care parameters based on the best and more updated available evidence for achieving minimum quality standards with adult patients thus diagnosed.

METHODOLOGY

A practical clinical guide was elaborated according to standards of the Methodological Guide of the Ministry of Social Protection. Recommendation from NICE90 and CANMAT guides were adopted and updated so as to answer the questions posed while de novo questions were developed.

RESULTS

Recommendations 5-22 corresponding to management of depression are presented.

Antidepressant use and the risk of upper gastrointestinal bleeding in psychiatric patients: a nationwide cohort study in Taiwan

The magnitude of risk between selective serotonin reuptake inhibitors and upper gastrointestinal bleeding (UGIB) is still unknown in patients with psychiatric diseases. The aim of this study was to quantify the risk of UGIB induced by use of antidepressants with different affinities for serotonin transporters in psychiatric patients using Taiwan's nationwide health insurance claims database. We conducted a propensity score- matched retrospective cohort study and identified 304,606 psychiatric patients who initiated antidepressant treatment during the 2005-2006 period. Antidepressants were classified as high- (HA group), intermediate- (IA group), or low-affinity (LA group) serotonin reuptake inhibitors. Patients in the LA group were matched 1:1 to those in the HA and IA groups according to their propensity scores. Subjects who were successfully matched were followed up from the date of antidepressant initiation to first hospitalization for UGIB, drug discontinuation, transition to or addition of antidepressants in another group, or the study's end (whichever occurred first). A total of 153,486 psychiatric patients were successfully matched, and 498 first UGIB events were identified. Compared with the LA group, patients in the HA group had a higher risk for UGIB (hazard ratio [HR], 1.38; 95% confidence interval [CI], 1.11-1.71). The HR (95% CI) of the IA group was 1.11 (95% CI, 0.88-1.41). The trend for elevated UGIB risk with increasing affinity of serotonin transporters was statistically significant (P < 0.01). Elderly patients and those with prior UGIB history were more susceptible to the harmful effects. Our findings suggest that the use of high-affinity serotonin reuptake inhibitors may increase the risk for UGIB in psychiatric patients.

Clinically relevant drug interactions in anxiety disorders

OBJECTIVE

Certain drugs used in the treatment of patients with anxiety disorders can interact with other psychotropic drugs and with pharmacological treatments for physical illnesses. There is a need for an updated comparative review of clinically relevant drug interactions in this area.

DESIGN

Relevant literature on drug interactions with medications used in the treatment of anxiety disorders was identified through a search in MEDLINE and EMBASE.

RESULTS

Drug interactions involving medications used to treat anxiety disorders may be pharmacokinetic, such as enzyme inhibition or induction in the cytochrome P450 system and transporter-mediated drug interactions, or pharmacodynamic, such as additive effects in causing drowsiness or additive effects at neurotransmitter receptors. Certain selective serotonin reuptake inhibitors (fluoxetine, fluvoxamine, and paroxetine) are particularly liable to be potentially involved in untoward pharmacokinetic interactions.

CONCLUSIONS

The potential for drug interactions with medications used in anxiety disorders should be the cause of clinical concern, particularly in elderly individuals. However, the liability for harmful drug interactions may be anticipated, and the risk reduced. Although not all interactions are clinically relevant, careful monitoring of clinical response and possible interactions is essential.

Selective serotonin re-uptake inhibiting antidepressants and the risk of overanticoagulation during acenocoumarol maintenance treatment

AIM

The aim of this study was to investigate the effects of co-medication with selective serotonin re-uptake inhibitors (SSRIs) on overanticoagulation during acenocoumarol maintenance treatment.

METHODS

All subjects from The Rotterdam Study who received acenocoumarol maintenance treatment between April 1 1991 and September 9 2009 were followed for the event of an international normalized ratio (INR) ≥6, until death, end of treatment or end of the study period. With the Andersen-Gill extension of the Cox proportional hazards model, risks for repeated events of overanticoagulation in relation to concomitant SSRI use were calculated.

RESULTS

The risk for overanticoagulation during acenocoumarol maintenance treatment was increased in combination with fluvoxamine (HR 2.63, 95% CI 1.49, 4.66) and venlafaxine (HR 2.19, 95% CI 1.21, 3.99). There was no increase in risk for the other SSRIs, but numbers of exposed cases were low for all SSRIs except paroxetine.

CONCLUSION

Fluvoxamine and venlafaxine were associated with a more than double risk of INR values ≥6 in acenocoumarol treated subjects.

Bleeding incidence with concomitant use of antidepressants and warfarin

INTRODUCTION

Bleeding is the major complication associated with warfarin therapy. Some antidepressants are also associated with increased bleeding risk. Warfarin and antidepressants are used frequently in combination, but it is unclear whether concomitant use increases the risk of bleeding beyond that with warfarin alone. The primary goal of this study was to determine whether the use of warfarin and an antidepressant increases the risk for bleeding outcomes compared with the use of warfarin alone. The secondary goal was to characterize the risk of bleeding in warfarin-treated patients taking one specific class of antidepressant, selective serotonin reuptake inhibitors (SSRIs).

MATERIALS AND METHODS

This was a retrospective, single-center, study of warfarin-treated patients prescribed (n = 46) and not prescribed (n = 54) an antidepressant. Medical records over 6 months were reviewed for international normalized ratio values, medical history, bleeding type and incidence, and hospitalization due to bleeding. Patients were included in the antidepressant group if they were taking concomitant warfarin and antidepressant therapy consistently for a period of 6 months and in the control group if they were not taking an antidepressant with warfarin.

RESULTS

The use of any antidepressant with warfarin was not associated with the incidence of any bleeding or major bleeding during the 6-month period. However, the use of an SSRI with warfarin was associated with an increase in any bleeding event (odds ratio 2.6, 95% confidence interval, 1.01-6.4 P = 0.04). The use of an SSRI remained a significant predictor of bleeding after accounting for other factors associated with bleeding risk.

CONCLUSIONS

Based on these data, it is important to clarify the interaction between warfarin and SSRIs in regard to bleeding risk given the high frequency of their concomitant use.

Incident user cohort study of risk for gastrointestinal bleed and stroke in individuals with major depressive disorder treated with antidepressants

OBJECTIVE

To examine the association between exposure to newer antidepressants and risk of gastrointestinal (GI) and other bleeding complications among individuals with major depressive disorder (MDD).

DESIGN

This study uses an incident user cohort design to compare associations between incidence of vascular/bleeding events and the relative affinity (low, moderate or high) of the antidepressant for the serotonin transporter during an exposure risk period for each patient.

SETTING

New England healthcare system electronic medical record database.

PARTICIPANTS

36 389 individuals with a diagnosis of MDD and monotherapy with a selective serotonin reuptake inhibitor, serotonin-norepinephrine reuptake inhibitor or other new-generation antidepressant were identified from among 3.1 million patients in a New England healthcare system.

PRIMARY AND SECONDARY OUTCOME MEASURES

Rates of bleeding or other vascular complications, including acute liver failure, acute renal failure, asthma, breast cancer and hip fractures.

RESULTS

601 GI bleeds were observed in the 21 462 subjects in the high-affinity group versus 333 among the 14 927 subjects in the lower affinity group (adjusted RR: 1.17, 95% CI 1.02 to 1.34). Similarly, 776 strokes were observed in the high-affinity group versus 434 in the lower affinity treatment group (adjusted RR: 1.18, 95% CI 1.06 to 1.32). No significant association with risk for a priori negative control outcomes, including acute liver failure, acute renal failure, asthma, breast cancer and hip fractures, was identified.

CONCLUSIONS

Use of antidepressants with high affinity for the serotonin transporter may confer modestly elevated risk for GI and other bleeding complications. While multiple methodologic limitations must be considered, these results suggest that antidepressants with lower serotonin receptor affinity may be preferred in patients at greater risk for such complications.

Clinically significant drug interactions with newer antidepressants

After the introduction of selective serotonin reuptake inhibitors (SSRIs), other newer antidepressants with different mechanisms of action have been introduced in clinical practice. Because antidepressants are commonly prescribed in combination with other medications used to treat co-morbid psychiatric or somatic disorders, they are likely to be involved in clinically significant drug interactions. This review examines the drug interaction profiles of the following newer antidepressants: escitalopram, venlafaxine, desvenlafaxine, duloxetine, milnacipran, mirtazapine, reboxetine, bupropion, agomelatine and vilazodone. In general, by virtue of a more selective mechanism of action and receptor profile, newer antidepressants carry a relatively low risk for pharmacodynamic drug interactions, at least as compared with first-generation antidepressants, i.e. monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants (TCAs). On the other hand, they are susceptible to pharmacokinetic drug interactions. All new antidepressants are extensively metabolized in the liver by cytochrome P450 (CYP) isoenzymes, and therefore may be the target of metabolically based drug interactions. Concomitant administration of inhibitors or inducers of the CYP isoenzymes involved in the biotransformation of specific antidepressants may cause changes in their plasma concentrations. However, due to their relatively wide margin of safety, the consequences of such kinetic modifications are usually not clinically relevant. Conversely, some newer antidepressants may cause pharmacokinetic interactions through their ability to inhibit specific CYPs. With regard to this, duloxetine and bupropion are moderate inhibitors of CYP2D6. Therefore, potentially harmful drug interactions may occur when they are coadministered with substrates of these isoforms, especially compounds with a narrow therapeutic index. The other new antidepressants are only weak inhibitors or are not inhibitors of CYP isoforms at usual therapeutic concentrations and are not expected to affect the disposition of concomitantly administered medications. Although drug interactions with newer antidepressants are potentially, but rarely, clinically significant, the use of antidepressants with a more favourable drug interaction profile is advisable. Knowledge of the interaction potential of individual antidepressants is essential for safe prescribing and may help clinicians to predict and eventually avoid certain drug combinations.

Helicobacter pylori and risk of upper gastrointestinal bleeding among users of selective serotonin reuptake inhibitors

BACKGROUND

A number of studies have reported a possible association between use of selective serotonin reuptake inhibitors (SSRIs) and serious upper gastrointestinal bleeding (UGB). We conducted this case-control study to assess if Helicobacter pylori (H. pylori) potentiates the risk of serious UGB in SSRI users.

MATERIAL AND METHODS

A population-based case-control study was conducted in the county of Funen, Denmark. Cases were 53 SSRI users with serious UGB whose H. pylori status on their bleeding date could be established. Controls (n = 723) were selected among subjects who participated in a population H. pylori screening study, and who were users of SSRIs. Data on drug exposure and medical history were retrieved from a prescription database and the county's patient register. Confounders were controlled for by unconditional logistic regression.

RESULTS

H. pylori infection increased the risk of serious UGB in patients using SSRI with an adjusted odds ratio (OR) of 2.73 (95% confidence interval (CI), 1.17-6.36). The adjusted OR for serious UGB among users of non-steroidal anti-inflammatory drugs (NSAIDs) and acetylsalicylic acid (ASA) were 3.91 (95% CI, 2.03-7.52) and 3.00 (95% CI, 0.94-9.54), respectively.

CONCLUSION

H. pylori infection increases the risk of SSRI-related serious UGB.

Antidepressant use and risk of adverse outcomes in older people: population based cohort study

OBJECTIVES

To investigate the association between antidepressant treatment and risk of several potential adverse outcomes in older people with depression and to examine risks by class of antidepressant, duration of use, and dose.

DESIGN

Cohort study of people aged 65 and over diagnosed as having depression.

SETTING

570 general practices in the United Kingdom supplying data to the QResearch primary care database.

PARTICIPANTS

60,746 patients diagnosed as having a new episode of depression between the ages of 65 and 100 years from 1 January 1996 to 31 December 2007 and followed up until 31 December 2008.

MAIN OUTCOME MEASURES

Hazard ratios associated with antidepressant use for all cause mortality, attempted suicide/self harm, myocardial infarction, stroke/transient ischaemic attack, falls, fractures, upper gastrointestinal bleeding, epilepsy/seizures, road traffic accidents, adverse drug reactions, and hyponatraemia, adjusted for a range of potential confounding variables. Hazard ratios were calculated for antidepressant class (tricyclic and related antidepressants, selective serotonin reuptake inhibitors, other antidepressants), dose, and duration of use and for commonly prescribed individual drugs.

RESULTS

54,038 (89.0%) patients received at least one prescription for an antidepressant during follow-up. A total of 1,398,359 antidepressant prescriptions were issued: 764,659 (54.7%) for selective serotonin reuptake inhibitors, 442,192 (31.6%) for tricyclic antidepressants, 2203 (0.2%) for monoamine oxidase inhibitors, and 189,305 (13.5%) for the group of other antidepressants. The associations with the adverse outcomes differed significantly between the antidepressant classes for seven outcomes. Selective serotonin reuptake inhibitors were associated with the highest adjusted hazard ratios for falls (1.66, 95% confidence interval 1.58 to 1.73) and hyponatraemia (1.52, 1.33 to 1.75) compared with when antidepressants were not being used. The group of other antidepressants was associated with the highest adjusted hazard ratios for all cause mortality (1.66, 1.56 to 1.77), attempted suicide/self harm (5.16, 3.90 to 6.83), stroke/transient ischaemic attack (1.37, 1.22 to 1.55), fracture (1.64, 1.46 to 1.84), and epilepsy/seizures (2.24, 1.60 to 3.15), compared with when antidepressants were not being used. Tricyclic antidepressants did not have the highest hazard ratio for any of the outcomes. Significantly different associations also existed between the individual drugs for the same seven outcomes; trazodone (tricyclic antidepressant), mirtazapine, and venlafaxine (both in the group of other antidepressants) were associated with the highest rates for some of these outcomes. Absolute risks over 1 year for all cause mortality were 7.04% for patients while not taking antidepressants, 8.12% for those taking tricyclic antidepressants, 10.61% for selective serotonin reuptake inhibitors, and 11.43% for other antidepressants.

CONCLUSIONS

Selective serotonin reuptake inhibitors and drugs in the group of other antidepressants were associated with an increased risk of several adverse outcomes compared with tricyclic antidepressants. Among individual drugs, trazodone, mirtazapine, and venlafaxine were associated with the highest risks for some outcomes. As this is an observational study, it is susceptible to confounding by indication, channelling bias, and residual confounding, so differences in characteristics between patients prescribed different antidepressant drugs that could account for some of the associations between the drugs and the adverse outcomes may remain. Further research is needed to confirm these findings, but the risks and benefits of different antidepressants should be carefully evaluated when these drugs are prescribed to older people.

Bleeding after percutaneous endoscopic gastrostomy is linked to serotonin reuptake inhibitors, not aspirin or clopidogrel

BACKGROUND

Percutaneous endoscopic gastrostomy (PEG) is an invasive procedure that can result in bleeding. Guidelines recommend discontinuing clopidogrel for 7 to 10 days, but not withholding aspirin, before PEG. Serotonin reuptake inhibitors (SRIs) have been associated with an increased risk of GI bleeding.

OBJECTIVE

To determine whether there is an association between periprocedural aspirin, clopidogrel, or SRI use and bleeding in patients who underwent PEG tube placement.

DESIGN

Retrospective cohort study.

SETTING

Large quaternary-care academic medical center.

PATIENTS

A total of 990 patients (525 men) with a median age of 69.8 years who underwent PEG from January 1999 to April 2009.

INTERVENTIONS

PEG tube placement.

MAIN OUTCOME MEASUREMENTS

GI bleeding.

RESULTS

Sixteen patients (1.6%) had evidence of bleeding during the first 48 hours after PEG, and 12 patients (1.2%) had evidence of bleeding between 48 hours and 14 days after PEG. Thirty-six patients (3.6%) received high-dose aspirin (>325 mg), 27 patients (2.7%) received clopidogrel (75 mg), and 99 patients (10%) received an SRI before PEG. Twenty-four patients (2.4%) received high-dose aspirin, 25 patients (2.5%) received clopidogrel, and 130 patients (13.1%) received an SRI after PEG. Multivariate analysis demonstrated no association between periprocedural use of aspirin (at any dose) or clopidogrel and post-PEG bleeding. However, SRIs administered 24 hours or less before PEG were associated with a significantly higher odds of post-PEG bleeding (adjusted odds ratio 4.1; 95% CI, 1.1-13.4; P = .04).

LIMITATIONS

Retrospective, single-center study with limited statistical power despite a relatively large cohort of patients.

CONCLUSIONS

Use of aspirin or clopidogrel before or after PEG was not associated with procedure-related bleeding. SRI use in the 24 hours before PEG was associated with an increased risk of bleeding.

Antidepressant-warfarin interaction and associated gastrointestinal bleeding risk in a case-control study

Background

Bleeding is the most common and worrisome adverse effect of warfarin therapy. One of the factors that might increase bleeding risk is initiation of interacting drugs that potentiate warfarin. We sought to evaluate whether initiation of an antidepressant increases the risk of hospitalization for gastrointestinal bleeding in warfarin users.

Methodology/Principal Findings

Medicaid claims data (1999–2005) were used to perform an observational case-control study nested within person-time exposed to warfarin in those ≥18 years. In total, 430,455 warfarin users contributed 407,370 person-years of warfarin use. The incidence rate of hospitalization for GI bleeding among warfarin users was 4.48 per 100 person-years (95% CI, 4.42–4.55). Each gastrointestinal bleeding cases was matched to 50 controls based on index date and state. Warfarin users had an increased odds ratio of gastrointestinal bleeding upon initiation of citalopram (OR = 1.73 [95% CI, 1.25–2.38]), fluoxetine (OR = 1.63 [95% CI, 1.11–2.38]), paroxetine (OR = 1.64 [95% CI, 1.27–2.12]), amitriptyline (OR = 1.47 [95% CI, 1.02–2.11]). Also mirtazapine, which is not believed to interact with warfarin, increased the risk of GI bleeding (OR = 1.75 [95% CI, 1.30–2.35]).

Conclusions/Significance

Warfarin users who initiated citalopram, fluoxetine, paroxetine, amitriptyline, or mirtazapine had an increased risk of hospitalization for gastrointestinal bleeding. However, the elevated risk with mirtazapine suggests that a drug-drug interaction may not have been responsible for all of the observed increased risk.

Selective serotonin reuptake inhibitors and gastrointestinal bleeding: a case-control study

Background

Selective serotonin reuptake inhibitors (SSRIs) have been associated with upper gastrointestinal (GI) bleeding. Given their worldwide use, even small risks account for a large number of cases. This study has been conducted with carefully collected information to further investigate the relationship between SSRIs and upper GI bleeding.

Methods

We conducted a case-control study in hospitals in Spain and in Italy. Cases were patients aged ≥18 years with a primary diagnosis of acute upper GI bleeding diagnosed by endoscopy; three controls were matched by sex, age, date of admission (within 3 months) and hospital among patients who were admitted for elective surgery for non-painful disorders. Exposures to SSRIs, other antidepressants and other drugs were defined as any use of these drugs in the 7 days before the day on which upper gastrointestinal bleeding started (index day).

Results

581 cases of upper GI bleeding and 1358 controls were considered eligible for the study; no differences in age or sex distribution were observed between cases and controls after matching. Overall, 4.0% of the cases and 3.3% of controls used an SSRI antidepressant in the week before the index day. No significant risk of upper GI bleeding was encountered for SSRI antidepressants (adjusted odds ratio, 1.06, 95% CI, 0.57–1.96) or for whichever other grouping of antidepressants.

Conclusions

The results of this case-control study showed no significant increase in upper GI bleeding with SSRIs and provide good evidence that the magnitude of any increase in risk is not greater than 2.

Association between selective serotonin reuptake inhibitors and gastrointestinal damage: advances and prospects

Selective serotonin reuptake inhibitors (SSRIs) are among the most commonly prescribed drugs in the world and have widely been used in the treatment of depression, because they have similar efficacy to tricyclic antidepressants and demonstrate a favorable safety and tolerability profile. However, with the increase in the number of patients receiving SSRIs, low-frequency adverse effects associated with use of SSRIs have become more prevalent. Since 1990, a number of case reports and epidemiological studies have described the risk of gastrointestinal bleeding in patients after the initiation of SSRI therapy. This article reviews the recent advances and future prospects for understanding the association between SSRIs and upper gastrointestinal bleeding.

Advances pertaining to the pharmacology and interactions of irreversible nonselective monoamine oxidase inhibitors

Recent advances clarifying the pharmacology and interactions of irreversible nonselective monoamine oxidase inhibitors that have not been considered in depth lately are discussed. These new data elucidate aspects of enzyme inhibition and pharmacokinetic interactions involving amine oxidases, cytochrome P450 enzymes, aminotransferases (transaminases), and decarboxylases (carboxy-lyases) and the effects of tyramine. Phenelzine and tranylcypromine remain widely available, and many publications have data relevant to this review. Their effect on CYP 450 enzymes is less than many newer drugs. Tranylcypromine only inhibits CYP 450 2A6 (selectively and potently). Phenelzine has no reported interactions, but, like isoniazid, weakly and irreversibly inhibits CYP 450 2C19 and 3A4 in vitro. It might possibly be implicated in interactions (as isoniazid is). Phenelzine has some clinically relevant inhibitory effects on amine oxidases, aminotransferases, and decarboxylases, and it lowers pyridoxal phosphate levels. It commonly causes pyridoxal deficiency, weight gain, sedation, and sexual dysfunction, but only rarely causes hepatic damage and failure, or neurotoxicity. The adverse effects and difficulties with monoamine oxidase inhibitors are less than previously believed or estimated, including a lower risk of hypertension, because the tyramine content in foods is now lower. Potent norepinephrine reuptake inhibitors have a strong protective effect against tyramine-induced hypertension. The newly discovered trace amine-associated receptors probably mediate the pressor response. The therapeutic potential of tranylcypromine and L-dopa in depression and Parkinson disease is worthy of reassessment. Monoamine oxidase inhibitors are not used to an extent proportionate with their benefits; medical texts and doctors' knowledge require a major update to reflect the evidence of recent advances.

Selective inhibitors of monoamine oxidase type B and the "cheese effect"

Potentiation of the cardiovascular and other effects of dietary tyramine by monoamine oxidase (MAO) inhibitors (cheese effect) has been a major limitation to clinical use of these drugs. The discovery that MAO exists in two distinct isoforms, MAO-A and MAO-B, together with the development of selective inhibitors of each isoform, enabled the understanding that selective inhibition of MAO-A, or inhibition of both isoforms, will cause cheese effect, but selective inhibition of MAO-B can be elicited without dangerous pressor reaction. This development has permitted the introduction of selective MAO-B inhibitors to clinical medicine for treatment of Parkinson's disease. This review describes the basic mechanisms involved in cheese effect, as well as providing information on tyramine levels in a variety of foodstuff, and surveys clinical information from tyramine pressor testing with the selective MAO-B inhibitors, selegiline and rasagiline.

Antiplatelet drug interactions

Both laboratory studies in healthy volunteers and clinical studies have suggested adverse interactions between antiplatelet drugs and other commonly used medications. Interactions described include those between aspirin and ibuprofen, aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), and the thienopyridine, clopidogrel, and drugs inhibiting CYP2C19, notably the proton pump inhibitors (PPI) omeprazole and esomeprazole. Other interactions between thienopyridines and CYP3A4/5 have also been reported for statins and calcium channel blockers. The ibuprofen/aspirin interaction is thought to be caused by ibuprofen blocking the access of aspirin to platelet cyclo-oxygenase. The thienopyridine interactions are caused by inhibition of microsomal enzymes that metabolize these pro-drugs to their active metabolites. We review the evidence for these interactions, assess their clinical importance and suggest strategies of how to deal with them in clinical practice. We conclude that ibuprofen is likely to interact with aspirin and reduce its anti-platelet action particularly in those patients who take ibuprofen chronically. This interaction is of greater relevance to those patients at high cardiovascular risk. A sensible strategy is to advise users of aspirin to avoid chronic ibuprofen or to ingest aspirin at least 2 h prior to ibuprofen. Clearly the use of NSAIDs that do not interact in this way is preferred. For the clopidogrel CYP2C19 and CYP3A4/5 interactions, there is good evidence that these interactions occur. However, there is less good evidence to support the clinical importance of these interactions. Again, a reasonable strategy is to avoid the chronic use of drugs that inhibit CYP2C19, notably PPIs, in subjects taking clopidogrel and use high dose H2 antagonists instead. Finally, anti-platelet agents probably interact with other drugs that affect platelet function such as selective serotonin reuptake inhibitors, and clinicians should probably judge patients taking such combination therapies as at high risk for bleeding.