Cardiovascular toxicity due to venlafaxine poisoning in adults: a review of 235 consecutive cases

Multiplexed quantification of venlafaxine and metabolites in human plasma by liquid chromatography-tandem mass spectrometry

BACKGROUND

Venlafaxine (VEN) and its O-demethylated metabolite, O-desmethylvenlafaxine (ODV), are commonly prescribed serotonin-norepinephrine reuptake inhibitors, approved for the treatment of depression and anxiety. Both are metabolized to inactive metabolites via cytochrome P450 enzymes. While previous studies have focused on quantifying VEN and ODV, bioanalytical methods for the simultaneous measurement of all metabolites are needed to fully characterize the pharmacology of VEN and ODV.

METHODS

K2EDTA plasma was spiked with VEN, ODV, N-desmethylvenlafaxine (NDV), N,O-didesmethylvenlafaxine (NODDV), and N,N-didesmethylvenlafaxine (NNDDV). Drugs and metabolites were extracted via protein precipitation and quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The multiplexed assay was validated in accordance with regulatory recommendations, and evaluated in remnant plasma samples from persons prescribed venlafaxine.

RESULTS

The analytical measuring range for venlafaxine and all four metabolites was 5-800 ng/mL. Standard curves were generated via weighted quadratic (NNDDV) or linear (VEN, ODV, NDV, NODDV) regression of calibrators. Inter-assay imprecision was between 1.9-9.3% for all levels of all analytes. Minor matrix effects were observed, and both recovery efficiency and process efficiency were >96% for all analytes. All other assay validation assessments met acceptance criteria. Drug concentrations measured from remnant plasma specimens obtained from patients with current venlafaxine prescriptions (37.5-450 mg/day) yielded NDDV, NDV, and NODDV metabolite concentrations in 6/21, 14/21, and 20/21 samples, respectively. The ratio of active to inactive analytes ranged from 0.74 to 14.5, with a median of 6.39.

CONCLUSIONS

An efficient and accurate LC-MS/MS method was developed and validated for the quantification of VEN, ODV, and all three inactive metabolites in plasma. The assay met all acceptance criteria, and may be used in future studies of the pharmacokinetics of these drugs.

Giant T waves and QT interval prolongation associated with guanfacine toxicity

INTRODUCTION

Guanfacine is a central α2-adrenergic receptor agonist that produces drowsiness, bradycardia, hypotension, and occasionally QT interval prolongation. We discuss giant T waves associated with guanfacine toxicity.

CASE SUMMARIES

Three patients presented to the hospital with histories and physical findings compatible with guanfacine toxicity. Supratherapeutic concentrations were confirmed in two of them. All three developed QT interval prolongation and giant T waves on the electrocardiogram. Giant T waves occur commonly in patients with acute myocardial infarct and hyperkalemia, as well as rarely with a number of other cardiac and non-cardiac causes.

CONCLUSION

Guanfacine toxicity may cause the novel electrocardiographic finding of 'giant T wave with QT interval prolongation'. Further studies are warranted to investigate the association between the novel electrocardiographic finding and guanfacine toxicity, as well as its diagnostic utility in such cases.

[Retrospective analysis of venlafaxine-induced hypoglycemia in patients with overdose]

INTRODUCTION

Recent publications relate the presence of hypoglycemia in venlafaxine (VLX) poisoning depending on the dose. Our aim was to analyze the clinical characteristics of patients who presented hypoglycemia induced by VLF overdose.

PATIENTS AND METHODS

Retrospective study carried out in the Balearic Islands (2020-2023).

INCLUSION CRITERIA

serum concentrations of VLX + O-desmethyl-venlafaxine (O-VLX)>800 ng/mL. The characteristics of patients with and without hypoglycemia were compared.

RESULTS

Twenty-one patients were included, 8 (38.1%) with hypoglycemia. No differences were found in the doses referred to in both groups. Peak concentrations of VLX + O-VLX (ng/mL) were 9,783 [4,459-17,976] in patients with hypoglycemia and 1,413 [930-1,719] in patients without hypoglycemia (p<0.0001). The presence of hypoglycemia was associated with: lower age and level of consciousness; and higher frequency of suicide attempts, seizures, mydriasis, tachycardia and serotonin syndrome, invasive respiratory support, fluid therapy and ICU admission (p<0.05).

CONCLUSIONS

The detection of hypoglycemia in a VLX overdose case is a readily available marker to suspect the severity of the patient. In any case, serum concentrations when available allow us to confirm intoxication.

Effect of CYP2D6, 2C19, and 3A4 Phenoconversion in Drug-Related Deaths

Molecular autopsy is a very important tool in forensic toxicology. However, many determinants, such as co-medication and physiological parameters, should be considered for optimal results. These determinants could cause phenoconversion (PC), a discrepancy between the real metabolic profile after phenoconversion and the phenotype determined by the genotype. This study's objective was to assess the PC of drug-metabolizing enzymes, namely CYP2D6, 2C19, and 3A4, in 45 post-mortem cases where medications that are substrates, inducers, or inhibitors of these enzymes were detected. It also intended to evaluate how PC affected the drug's metabolic ratio (MR) in four cases. Blood samples from 45 cases of drug-related deaths were analyzed to detect and determine drug and metabolite concentrations. Moreover, all the samples underwent genotyping utilizing the HaloPlex Target Enrichment System for CYP2D6, 2C19, and 3A4. The results of the present study revealed a statistically significant rate of PC for the three investigated enzymes, with a higher frequency of poor metabolizers after PC. A compatibility was seen between the results of the genomic evaluation after PC and the observed MRs of venlafaxine, citalopram, and fentanyl. This leads us to focus on the determinants causing PC that may be mainly induced by drug interactions. This complex phenomenon can have a significant impact on the analysis, interpretation of genotypes, and accurate conclusions in forensic toxicology. Nevertheless, more research with more cases in the future is needed to confirm these results.

Biodetoxification Using Intravenous Lipid Emulsion, a Rescue Therapy in Life-Threatening Quetiapine and Venlafaxine Poisoning: A Case Report

The administration of intravenous lipid emulsion (ILE) is a proven antidote used to reverse local anesthetic-related systemic toxicity. Although the capacity of ILE to generate blood tissue partitioning of lipophilic drugs has been previously demonstrated, a clear recommendation for its use as an antidote for other lipophilic drugs is still under debate. Venlafaxine (an antidepressant acting as a serotonin-norepinephrine reuptake inhibitor (SNRI)) and quetiapine (a second-generation atypical antipsychotic) are widely used in the treatment of psychotic disorders. Both are lipophilic drugs known to induce cardiotoxicity and central nervous depression. We report the case of a 33-year-old man with a medical history of schizoaffective disorder who was admitted to the emergency department (ED) after having been found unconscious due to a voluntary ingestion of 12 g of quetiapine and 4.5 g of venlafaxine. Initial assessment revealed a cardiorespiratory stable patient but unresponsive with a GCS of 4 (M2 E1 V1). In the ED, he was intubated, and gastric lavage was performed. Immediately after the admission to the intensive care unit (ICU), his condition quickly deteriorated, developing cardiovascular collapse refractory to crystalloids and vasopressor infusion. Junctional bradycardia occurred, followed by spontaneous conversion to sinus rhythm. Subsequently, frequent ventricular extrasystoles, as well as patterns of bigeminy, trigeminy, and even episodes of non-sustained ventricular tachycardia, occurred. Additionally, generalized tonic-clonic seizures were observed. Alongside supportive therapy, antiarrhythmic and anticonvulsant therapy, intravenous lipid emulsion bolus, and continuous infusion were administered. His condition progressively improved over the following hours, and 24 h later, he was tapered off the vasopressor. On day 2, the patient repeated the cardiovascular collapse and a second dose of ILE was administered. Over the next few days, the patient's clinical condition improved, and he was successfully weaned off ventilator and vasopressor support. ILE has the potential to become a form of rescue therapy in cases of severe lipophilic drug poisoning and should be considered a viable treatment for severe cardiovascular instability that is refractory to supportive therapy.

Lethal vortioxetine poisoning? A forensic investigation

Vortioxetine is an antidepressant recently licensed in the US and EU for the treatment of major depressive disorder. No fatalities from vortioxetine overdose have been reported, yet. Two cases of attempted suicide are described in the literature, although no toxicological analyzes were conducted. Vortioxetine concentrations found in blood and organs in a case of a probable acute lethal intoxication are reported here. A 65-year-old woman was found on the floor behind her bed with no vital signs. The woman was recently on vortioxetine 10 mg/day for major depression, anxiety, and psychotic attacks. Vortioxetine was quantified in blood, brain, liver, kidney, and lung samples by LC-MS/MS. Vortioxetine concentrations were: 1.197 ng/ml in the blood, 804 ng/g in the brain, 8.992 ng/g in the lung, 1.389 ng/g in the liver, 292 in the kidney. No other substance was found. In the case reported here, the blood concentration was approximately 35-135 times higher than the antemortem therapeutic value. Histological examination showed signs of a probable sudden cardiac death following to arrhythmia, with no evidence of myocardial infarction. The present case indicate that blood concentrations close to 1,000 ng/mL could lead to death, involving probably to a cardiac toxicity.

The Risk of Fatal Arrhythmias in Post-Myocardial Infarction Depression in Association With Venlafaxine

Venlafaxine is a second line anti-depressant and the most commonly used in the treatment of selective serotonin reuptake inhibitor nonresponders in major depression; due to its effects on the noradrenergic and serotonergic systems as a serotonin and norepinephrine reuptake inhibitor, there has been considerable apprehension regarding its use in patients with cardiovascular diseases, particularly post-myocardial infarction depression, some of the feared adverse effects include QT prolongation, arrhythmias including torsades de pointes and sudden cardiac death. We tried to resolve the facts regarding the risks associated with venlafaxine use in cardiac patients. We have reviewed all the relevant information up to May 2022 regarding the risks of venlafaxine use in cardiovascular disease, particularly with a focus on post-myocardial infarction depression, and gathered around 350 articles in our research and narrowed it down to 49 articles. The database used was PubMed and the keywords used were venlafaxine, arrhythmia, major depression, post-myocardial infarction, and ventricular tachycardia. We carefully screened all relevant articles and found articles supporting and refuting the effects of venlafaxine in increasing cardiovascular morbidity and mortality. We have concluded that there is a significant variability due to confounding factors affecting individual cases. Overall there is no increased arrhythmia risk in comparison with other anti-depressants except in high-risk cases such as with pre-existing cardiovascular disease, certain genotypes, and other co-morbidities. Any patient with a high risk of arrhythmias due to any etiology should receive a screening electrocardiogram before venlafaxine prescription for baseline QT interval and periodically while on therapy to check for changes. We encourage further research, including randomized clinical trials and post-marketing surveillance regarding the use of venlafaxine in high-risk cases such as patients with multiple co-morbidities, elderly patients, or patients with certain genotypes.

Successful use of extended cardiopulmonary resuscitation followed by extracorporeal oxygenation after venlafaxine-induced takotsubo cardiomyopathy and cardiac arrest: a case report

Background

Severe venlafaxine intoxication may cause arrhythmias, cardiac failure, and even cardiac arrest.

Case presentation

A 48-year-old caucasian male with an extensive psychiatric history ingested a high dose of venlafaxine causing a serum venlafaxine concentration of 12.6 mg/L 24 hours after ingestion. Seven hours post-ingestion, he experienced tonic–clonic seizures, and 8 hours later, takotsubo cardiomyopathy was recognized followed by cardiac arrest. The patient was resuscitated with prolonged cardiopulmonary resuscitation including ongoing automatic external compressions during helicopter transportation to a tertiary hospital for extracorporeal membrane oxygenation treatment. Despite a cardiopulmonary resuscitation duration of 2 hours, 36 hours of extracorporeal membrane oxygenation, and a total of 30 days of intensive care, the patient made a full recovery.

Conclusion

In cases of intoxication-induced cardiac arrests among otherwise young and healthy patients, prolonged cardiopulmonary resuscitation and extracorporeal circulation can be a life-saving bridge to recovery.

Case Report: Co-occurrence of Myocarditis and Thrombotic Microangiopathy Limited to the Heart in a COVID-19 Patient

We report on an impressive case of a previously healthy 47-year-old female Caucasian SARS-CoV-2 positive patient who died within 48 h after initial cardiac symptoms. Autopsy revealed necrotizing myocarditis and extensive microthrombosis as the cause of death. The interesting feature of this case is the combination of both myocarditis and extensive localized microthrombosis of cardiac capillaries. Microthrombosis was not present in other organs, and the patient did not show typical features of diffuse alveolar damage in the lungs. Taken together, our morphologic findings illustrate the angiocentric, microangiopathic, thromboinflammatory disease with significant thrombotic diathesis prevalent in COVID-19, which has been previously described in the literature, likely warranting thromboprophylaxis even in oligosymptomatic circumstances. This case also delineates several potential etiologies for microthrombosis, i.e., inflammatory reactions and primary hypercoagulative states. Further systematic analyses on risk stratification for receipt of prophylactic anticoagulation in COVID-19 are urgently required.

Lack of an Effect of Supratherapeutic Dose of Venlafaxine on Cardiac Repolarization in Healthy Subjects

This single-center, randomized, 3-way crossover thorough QT study evaluated the effect of steady-state supratherapeutic venlafaxine (Effexor) on cardiac repolarization. Fifty-four healthy adults received double-blinded extended-release venlafaxine 450 mg/d and placebo and open-label positive-control moxifloxacin 400 mg. The postdose QT intervals corrected for heart rate using the Fridericia formula (QTcF) were assessed on day 14 with an analysis of covariance using a mixed-effects model. At each time, the upper bound of the 2-sided 90%CI for time-matched least-squares (LS) mean difference between venlafaxine and placebo did not exceed the predefined cutoff of 10 milliseconds; the highest 90%CI upper bound was 5.8 milliseconds 24 hours postdose, demonstrating the lack of effect of venlafaxine on the QTc interval (primary objective). Assay sensitivity was established because the lower bound of the 2-sided 90%CI for LS mean difference in QTcF between moxifloxacin and placebo was 7.413 milliseconds on day 14 (postdose 3 hours). The exposure-response analysis demonstrated no evidence of increase in QTcF with increase in venlafaxine and desvenlafaxine concentrations. Also, supratherapeutic venlafaxine was found to be safe and well tolerated. Overall, the results demonstrated the lack of significant prolongation of the QTc interval with supratherapeutic venlafaxine 450 mg/d.

Glutathione conjugation and protein modification resulting from metabolic activation of venlafaxine in vitro and in vivo

Venlafaxine (VLF), an antidepressant agent, is widely used to combat major depressive disorders, particularly for the treatment of selective serotonin reuptake inhibitor-resistant depression. VLF has been shown to cause liver injury. The present study aimed to investigate the metabolic activation of VLF and explore the mechanisms of hepatotoxicity induced by VLF.One glutathione (GSH) conjugate and one cysteine conjugate were both detected in mouse and human liver microsomal incubations containing VLF and GSH or cysteine. The two conjugates were also detected in cultured mouse primary hepatocytes and bile of rats after exposure to VLF. The in vitro and in vivo studies demonstrated that VLF was metabolized to a quinone methide intermediate reactive to GSH and cysteine residues of hepatic protein. The observed protein covalent binding revealed dose-dependency. The metabolic activation of VLF was P450-dependent, and CYP3A4 was found as the predominant enzyme involved in the bioactivation process.These findings facilitate better understanding of the metabolic activation-hepatotoxicity relationship of VLF and provide chemists with information about new potential structural alerts during drug design process.

Toward a broader view of mechanisms of drug cardiotoxicity

Cardiotoxicity, defined as toxicity that affects the heart, is one of the most common adverse drug effects. Numerous drugs have been shown to have the potential to induce lethal arrhythmias by affecting cardiac electrophysiology, which is the focus of current preclinical testing. However, a substantial number of drugs can also affect cardiac function beyond electrophysiology. Within this broader sense of cardiotoxicity, this review discusses the key drug-protein interactions known to be involved in cardiotoxic drug response. We cover adverse effects of anticancer, central nervous system, genitourinary system, gastrointestinal, antihistaminic, anti-inflammatory, and anti-infective agents, illustrating that many share mechanisms of cardiotoxicity, including contractility, mitochondrial function, and cellular signaling.

Pitfalls and challenges associated with phenoconversion in forensic toxcicology

PURPOSE

In recent years, several publications have demonstrated the interest and the usefulness of pharmacogenetics in forensic toxicology. However, this approach remains namely focused on DNA-based phenotype, which may potentially lead to misinterpretation. Other determinants such as co-medication or physiological parameters may also impact the phenotype. This article aims to highlight the importance of considering such determinants in forensic toxicology, through the original case of a heroin-related fatality.

METHOD

Ethanol concentration determination and toxicological screening were performed using gas chromatography with flame ionization detection, liquid chromatography with diode array detection and gas chromatography with mass spectrometry detection. CYP2C19 and CYP2D6 genotypes were determined by Taqman® real-time PCR analyses.

RESULTS

Femoral blood analyses revealed the presence of ethanol, morphine, codeine, venlafaxine (VEN), O-desmethylvenlafaxine (ODV) and N-desmethylvenlafaxine (NDV), paroxetine, and risperidone. 6-acetylmorphine was also identified in urine. VEN, paroxetine and risperidone were quantified at supra-therapeutic or toxic blood concentrations. NDV was not quantified. The metabolic ratio of VEN (ODV to VEN) was exceptionally low (about 0.7). Pharmacogenetics testing showed that the patient was heterozygous for the CYP2C19*2 loss-of-function allele, which predict an intermediate metabolism for CYP2C19. None of the deficient CYP2D6 alleles investigated were identified. Those results suggest an extensive CYP2D6-metabolism phenotype.

CONCLUSION

A discrepancy was seen between the results of the genomic evaluation and the observed metabolic ratio of VEN. This tends to exclude a genetic origin and lead us to formulate other hypotheses, such as phenoconversion that may have been induced by drug interaction involving patients' regular medications. Phenoconversion is as a complex phenomenon that leads to genotype-phenotype mismatch without any genetic abnormality particularly described for cytochromes P450 2D6 and 2C19. Although transient, phenoconversion can have a significant impact on the analysis and interpretation of genotype-focused clinical outcomes correlation and in forensic toxicology conclusions.

Hypertension and orthostatic hypotension with venlafaxine treatment in depressed older adults

BACKGROUND

Venlafaxine, a serotonin-norepinephrine reuptake inhibitor, is often used as first- or second-line therapy for depression in older adults. It can be associated with adverse blood pressure (BP) effects.

METHODS

Adults ⩾60 years of age in a current major depressive episode were treated in a protocolized manner with venlafaxine XR; 429 participants were treated for 8-16 weeks with a daily dose up to 300 mg to achieve remission from depression. Cardiac measures included sitting and standing BP and heart rate.

RESULTS

Of participants who were normotensive at baseline, 6.5% were found to have elevated BP during the study (1.9% <225 mg/day; 9.8% ⩾225 mg/day). There was no significant change in mean BP in the overall sample, or in the subgroup treated with doses ⩾225 mg/day. Additionally, 20.1% of the participants who did not have orthostatic hypotension at baseline were found to have orthostatic hypotension (16.8% <225 mg/day; 22.4% ⩾225 mg/day). Participants with new-onset orthostatic hypotension were significantly more likely to fall than the other participants.

CONCLUSION

A large proportion of older adults treated with venlafaxine experience orthostatic hypotension, putting them at risk for falls. A smaller proportion experience elevated BP. Older patients prescribed venlafaxine, particularly at high doses, should be advised and counseled about these adverse effects.

Drug Interactions of Psychiatric and COVID-19 Medications

INTRODUCTION

Coronavirus disease 2019 (COVID-19) has become a pandemic with 1771514 cases identified in the world and 70029 cases in Iran until April 12, 2020. The co-prescription of psychotropics with COVID-19 medication is not uncommon. Healthcare providers should be familiar with many Potential Drug-Drug Interactions (DDIs) between COVID-19 therapeutic agents and psychotropic drugs based on cytochrome P450 metabolism. This review comprehensively summarizes the current literature on DDIs between antiretroviral drugs and chloroquine/hydroxychloroquine, and psychotropics, including antidepressants, antipsychotics, mood stabilizers, and anxiolytics.

METHODS

Medical databases, including Google Scholar, PubMed, Web of Science, and Scopus were searched to identify studies in English with keywords related to psychiatric disorders, medications used in the treatment of psychiatric disorders and COVID-19 medications.

RESULTS

There is a great potential for DDIs between psychiatric and COVID-19 medications ranging from interactions that are not clinically apparent (minor) to those that produce life-threatening adverse drug reactions, or loss of treatment efficacy. The majority of interactions are pharmacokinetic interactions via the cytochrome P450 enzyme system.

CONCLUSION

DDIs are a major concern in the comorbidity of psychiatric disorders and COVID-19 infection resulting in the alteration of expected therapeutic outcomes. The risk of toxicity or lack of efficacy may occur due to a higher or lower plasma concentration of medications. However, psychiatric medication can be safely used in combination with COVID-19 pharmacotherapy with either a wise selection of medication with the least possibility of interaction or careful patient monitoring and management.

The Effect of Venlafaxine on Electrocardiogram Intervals During Treatment for Depression in Older Adults

PURPOSE/BACKGROUND

Venlafaxine is a commonly used antidepressant with both serotonergic and noradrenergic activity. There are concerns that it may prolong the corrected QT interval (QTc), and older adults may be at higher risk for this adverse effect, especially at higher dosages of the medication.

METHODS/PROCEDURES

In this secondary analysis of a prospective clinical trial, we measured changes in QTc and other electrocardiogram (ECG) parameters in 169 adults 60 years or older with a major depressive disorder treated acutely with venlafaxine extended release up to 300 mg daily. We examined the relationship of venlafaxine dosage and ECG parameters, as well as the relationship between serum levels of venlafaxine and ECG parameters.

FINDINGS/RESULTS

Venlafaxine exposure was not associated with an increase in QTc. Heart rate increased with venlafaxine treatment, whereas the PR interval shortened, and QRS width did not change significantly. The QTc change from baseline was not associated with venlafaxine dosages or serum concentrations. Age, sex, cardiovascular comorbidities, and depression remission status did not predict changes in QTc with venlafaxine.

IMPLICATIONS/CONCLUSIONS

Venlafaxine treatment did not prolong QTc or other ECG parameters, even in high dosages in older depressed adults. These findings indicate that venlafaxine does not significantly affect cardiac conduction in most older patients.

Bradycardia caused by interaction of venlafaxine and cyclosporine: A case report

Background:

Selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) are prescribed widely for the treatment of depression, anxiety disorders and other psychiatric disorders. Although antidepressants are considered as a safety drug category but unexpected cardiovascular events have been reported as the most serious complications. The aim of this study was to introduce a case presentation on bradycardia due to the drug interference of venlafaxine and cyclosporine.

Case presentation:

The patient was a 38-year old woman diagnosed with systemic lupus erythematosus 5 years ago, who was admitted to a general educational hospital in northern Iran due to intensified rheumatologic symptoms and complaining about abdominal pain. Cyclosporine tab were administered to the patient, 50 mg twice daily. Two weeks after the administration of cyclosporine, the level of blood cyclosporine was checked. The patient became bradycardic after starting a single dose of venlafaxine (heart rate 52 ppm). Cardiac assessment showed no reason for bradycardia and it subsided after a drop of venlafaxine.

Conclusion:

As a result of the potential adverse drug interactions between cyclosporine and antidepressants such as venlafaxine, physicians should be aware of the possibility of bradycardia in the simultaneous prescription of these drugs in cases.

Choosing among second-generation antidepressant treatments for depressed patients with cardiac diseases

Objectives: The present paper aimed to assist physicians in the accurate choice among second-generation agents (SGAs) for patients with cardiovascular disease (CVD). Methods: We reviewed the published pharmacokinetic (PK) and pharmacodynamic (PD) clinical data that report potential -or absence of- drug interactions between second-generation agents (SGAs) and CVD drugs most commonly used in cardiology, including antiplatelet drugs and anticoagulants, statins, beta-blockers, angiotensin-converting enzyme inhibitors, calcium channel blockers, diuretics and the antiarrhythmic drugs amiodarone and digoxin. We also reviewed the cardiovascular safety profile that has been published for each class of SGAs and side effects reported by patients with CVD. Results: Most relevant PK/PD data about SGAs and CVD drugs are based on small studies or detailed case reports. In many cases, the drug interactions are at most assessed in healthy volunteers so that the clinical relevance of findings needs further investigation in patients with CVD. Case reports of serious, sometimes fatal reactions due to concomitant administration of certain drugs require careful consideration. The major cardiac side effects of SGAs include HR increase, postural hypotension and slight prolongation of the intraventricular conduction time and QT interval. On normal dosage of antidepressants, both advanced heart block and ventricular arrhythmias could occur in patients with severe heart disease, together with clinically important loss of myocardial contractile force. Conclusions: Data reported in the present review should help physicians about their decision-making processes that govern SGAs use in CVD patients.

Literature review of the evidence regarding intravenous lipid administration in drug-induced cardiotoxicity

Introduction: Intravenous lipid emulsion (ILE) administration is capable of reversing the acute cardiac and neurological toxicity caused by local anesthetic agents. In recent years, ILE has also been explored as a potential antidote for cardiotoxicity caused by non-anesthetic agents too. Areas covered: The potential mechanisms, safety, and efficacy of this approach are considered. Data were sought from published reports listed in PubMed and EMBASE, and abstracts of meetings of the North American Congress of Clinical Toxicology and European Association of Poisons Centres and Clinical Toxicologists. There were reports involving 298 patients where ILE has been administered for severe drug toxicity. Clinical improvement was observed in 57 of 59 patients with local anesthetic toxicity (96.6%); there were 239 patients where toxicity was due to non-anesthetic agents, and ILE apparently improved clinical outcome in 215 (72.1%). Expert opinion: Response rates were similar between ILE treated toxicity caused by lipid soluble and non-lipid soluble drugs. Potential adverse effects of ILE include interference with laboratory assays, acute pancreatitis, and adult respiratory distress syndrome, although the rate of occurrence is difficult to ascertain.

Effect of pre-gestational stress and prenatal venlafaxine administration on cardiovascular system of rat offspring

A number of pregnant women all over the world suffer from depression and are treated during gestation with antidepressants, mostly with selective serotonin reuptake inhibitors or selective serotonin and norepinephrine reuptake inhibitors. Exposure to prenatal stress is also a great risk factor for a developing fetus and could be responsible for altered fetal development or various neurobehavioral disturbances of a child. Administration of selective serotonin and norepinephrine reuptake inhibitor venlafaxine is associated with various cardiovascular adverse effects, such as tachycardia, increased blood pressure, arrhythmias and hypertensive crisis. The aim of this study was to focus on the effect of pre-gestational chronic mild unpredictable stress and/or administration of antidepressant venlafaxine (10 mg/kg/day, p. o.) on specific parameters, determining the function of the cardiovascular system of male and female rat offspring. Blood pressure and standard ECG were recorded in the offspring. Exposure to pre-gestational stress did not cause significant changes in the systolic, diastolic blood pressure and pulse frequency either in males or in females, compared to the unexposed control animals. Pre-gestational stress caused the shortening of QT interval and prolongation of QRS complex duration in males. On the other hand, in females, the effects of pre-gestational stress were potentiated by the administration of venlafaxine and resulted in elevated systolic and diastolic blood pressure, prolonged QT interval and shortened QRS complex duration, compared to the control. In conclusion, the female rat offspring are more sensitive to exposure to pre-gestational, to chronic mild unpredictable stress and venlafaxine.

Depression, antidepressants, and the risk of non-valvular atrial fibrillation: A nationwide Danish matched cohort study

Background

Depression is associated with an increased risk of a series of cardiovascular diseases and with increased symptom burden in patients with atrial fibrillation. The aim of this study was to determine the association between depression as well as antidepressant treatment and the risk of incident atrial fibrillation.

Design

A nationwide register-based study comparing the atrial fibrillation risk in all Danes initiating antidepressant treatment from 2000 to 2013 ( N = 785,254) with that in a 1:5-matched sample from the general population.

Methods

Cox regression was used to estimate adjusted hazard ratios (aHRs) and associated 95% confidence intervals (95% CIs), both after initiation of treatment and in the month before when patients were assumed to have medically untreated depression.

Results

Antidepressant treatment was associated with a three-fold higher risk of atrial fibrillation during the first month (aHR = 3.18 (95% CI: 2.98–3.39)). This association gradually attenuated over the following year (aHR = 1.37 (95% CI: 1.31–1.44) 2–6 months after antidepressant therapy initiation, and aHR = 1.11 (95% CI: 1.06–1.16) 6–12 months after). However, the associated atrial fibrillation risk was even higher in the month before starting antidepressant treatment (aHR = 7.65 (95% CI: 7.05–8.30) from 30 to 15 days before, and aHR = 4.29 (95% CI: 3.94–4.67) the last 15 days before). Overall, 0.4% of patients were diagnosed with atrial fibrillation from 30 days before to 30 days after antidepressant treatment.

Conclusions

Antidepressant users had a substantially increased atrial fibrillation risk, particularly before treatment initiation. Whether this mirrors a causal relation between depression and atrial fibrillation may have large consequences for public health and should be discussed.

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.

Psychotropic Pharmacotherapy Associated With QT Prolongation Among Veterans With Posttraumatic Stress Disorder

Background: In 2012, the Food and Drug Administration issued Drug Safety Communications on several drugs associated with QT prolongation and fatal ventricular arrhythmias. Among these was citalopram, a selective serotonin reuptake inhibitor (SSRI) approved for depression and commonly used for posttraumatic stress disorder (PTSD). Evaluation of the risk for QT prolongation among other psychotropic drugs for individuals with PTSD remains limited. Objective: Explore psychotropic drugs associated with QT prolongation among veterans with PTSD. Methods: Patients in the Veterans Health Administration in 2006-2009 with PTSD and QT prolongation (176 cases) were matched 1:4 on age, gender, visit date and setting, and physical comorbidity. Classification trees assessed QT prolongation risk among prescribed medications (n=880). Results: Receipt of any drug with known risk of QT prolongation varied by group (23% QT cases vs 15% control, p<0.01). Psychotropic medications conferring significant risks included ziprasidone (3% vs 1%, p=0.02) and buspirone (6% vs 2%, p=0.01). Increased risk was not observed for the SSRIs, citalopram and fluoxetine. Classification trees found that sotalol and amitriptyline carried greater risk among cardiac patients and methadone, especially if prescribed with quetiapine, among noncardiac patients. Per adjusted survival model, patients with QT prolongation were at increased risk for death (hazard ratio=1.60; 95% CI=1.04-2.44). Conclusions: Decision models are particularly advantageous when exploring nonlinear relationships or nonadditive interactions. These findings may potentially affect clinical decision-making concerning treatment for PTSD. For patients at higher risk of QT prolongation, antidepressants other than amitriptyline should be considered. Medications for comorbid conditions should also be closely monitored for heightened QT prolongation risk.

How Does Usage of Serotonin Noradrenaline Reuptake Inhibitors Affect Intraocular Pressure in Depression Patients?

PURPOSE

To evaluate anterior segment parameters and intraocular pressure (IOP) modifications in patients using serotonin noradrenaline reuptake inhibitors (SNRIs) due to major depressive disorder.

METHODS

This cross-sectional study included 170 eyes of 85 subjects. All subjects were divided into three groups: group 1 included 44 healthy control subjects, group 2 included 22 patients receiving antidepressants for 1 week to 6 months, and group 3 included 19 patients receiving antidepressants for >6 months. All subjects underwent a detailed ophthalmologic examination, including gonioscopy. Anterior segments of all subjects were evaluated with the Scheimpflug system and pupil diameter (PD), central corneal thickness, anterior chamber depth (ACD), anterior chamber volume, and anterior chamber angle (ACA) measurements were enrolled.

RESULTS

The median IOP was significantly lower in patients using antidepressants [16.0 (11.0-21.0) mmHg] than the control group [17.5 (12.0-21.0) mmHg] (P = 0.041). The PD was significantly larger in patients using antidepressants [3.56 (2.29-5.60) mm] than the control group [2.95 (2.00-4.40) mm] (P = 0.000). In the study group, PD was also significantly larger in patients using SNRIs for ≥6 months [3.67 (2.38-5.08) mm] than <6 months [3.31 (2.29-5.60) mm] (P = 0.000). The median ACD was significantly lower in patients using antidepressants for ≥6 months [3.21 (2.52-4.06) mm] than the control group [3.44 (2.63-4.29) mm] (P = 0.000). ACAs were measured between 25° and 55° by Scheimpflug imaging.

CONCLUSIONS

Treatment of SNRIs causes mydriasis and decrease in width of ACD. These changes may not increase IOP as long as the patient has an open angle. SNRIs lead to decrease in IOP particularly in long-term usage.

Serotonin norepinephrine re-uptake inhibitor (SNRI)-, selective norepinephrine reuptake inhibitor (S-NRI)-, and exogenously administered norepinephrine-induced takotsubo syndrome: Analysis of published cases

BACKGROUND

Takotsubo syndrome (TS) may be triggered by numerous physical stress factors including exogenous Norepinephrine administration. The aim of this study is to report on the clinical features and outcome of serotonin-norepinephrine reuptake inhibitor (SNRI)-, selective NRI (S-NRI)-, and exogenously administered norepinephrine-induced TS in a largest possible cohort of published cases.

METHODS

A computer assisted search of the electronic data base Pubmed was performed from 1990 to August 2016. All cases deemed to have SNRI-, S-NRI-, and norepinephrine-induced TS were retrieved.

RESULTS

Twenty two cases of SNRI-, S-NRI-, and norepinephrine-induced TS were retrieved from the literature. At presentation, the 22 patients with TS were 11 to 82years of age (mean age 49.9±20years). Seventeen of 21 (81%) of the patients were women. The most common presenting symptom was chest pain, which occurred in 59% of cases. The TS localization pattern was apical in 68%, mid-ventricular in 13.6%, basal in 13.6% and global in 4.5% of cases. Complications occurred in 7 of 22 (32%) with more complications in exogenously administered norepinephrine-induced TS (4 of 6, 66.7%) than SNRI-, and S-NRI-induced TS (3 of 16, 18, 8%) (p=0.054). All 4 male patients in the study developed complications. One patient (exogenous norepinephrine-induced TS) died during hospitalization.

CONCLUSION

The SNRI-, and S-NRI-induced TS have clinical features, complications and course comparable to that of all-TS population cohorts, whereas the exogenously administered norepinephrine-induced TS has a more dramatic clinical presentation and complication rates, which resembles that of exogenously administered epinephrine-induced TS.

Venlafaxine-Induced Cytotoxicity Towards Isolated Rat Hepatocytes Involves Oxidative Stress and Mitochondrial/Lysosomal Dysfunction

Purpose: Depression is a public disorder worldwide. Despite the widespread use of venlafaxine in the treatment of depression, it has been associated with the incidence of toxicities. Hence, the goal of the current investigation was to evaluate the mechanisms of venlafaxine-induced cell death in the model of the freshly isolated rat hepatocytes. Methods: Collagenase-perfused rat hepatocytes were treated with venlafaxine and other agents. Cell damage, reactive oxygen species (ROS) formation, lipid peroxidation, mitochondrial membrane potential decline, lysosomal damage, glutathione (GSH) level were analyzed. Moreover, rat liver mitochondria were isolated through differential centrifugation to assess respiratory chain functionality. Results: Our results demonstrated that venlafaxine could induce ROS formation followed by lipid peroxidation, cellular GSH content depletion, elevated GSSG level, loss of lysosmal membrane integrity, MMP collapse and finally cell death in a concentration-dependent manner. N-acetyl cysteine, taurine and quercetine significantly decreased the aforementioned venlafaxine-induced cellular events. Also, radical scavenger (butylatedhydroxytoluene and α-tocopherol), CYP2E1 inhibitor (4-methylpyrazole), lysosomotropic agents (methylamine and chloroquine), ATP generators (L-gluthamine and fructose) and mitochondrial pore sealing agents (trifluoperazine and L-carnitine) considerably reduced cytotoxicity, ROS generation and lysosomal leakage following venlafaxine treatment. Mitochondrion dysfunction was concomitant with the blockade of the electron transfer complexes II and IV of the mitochondrial respiratory system. Conclusion: Therefore, our data indicate that venlafaxine induces oxidative stress towards hepatocytes and our findings provide evidence to propose that mitochondria and lysosomes are of the primary targets in venlafaxine-mediated cell damage.

Intravenous Lipid Emulsion as an Antidote for the Treatment of Acute Poisoning: A Bibliometric Analysis of Human and Animal Studies

In recent years, there has been increasing interest in the role of intravenous lipid formulations as potential antidotes in patients with severe cardiotoxicity caused by drug toxicity. The aim of this study was to conduct a comprehensive bibliometric analysis of all human and animal studies featuring lipid emulsion as an antidote for the treatment of acute poisoning. The Scopus database search was performed on 5 February 2016 to analyse the research output related to intravenous lipid emulsion as an antidote for the treatment of acute poisoning. Research indicators used for analysis included total number of articles, date (year) of publication, total citations, value of the h-index, document types, countries of publication, journal names, collaboration patterns and institutions. A total of 594 articles were retrieved from Scopus database for the period of 1955-2015. The percentage share of global intravenous lipid emulsion research output showed that research output was 85.86% in 2006-2015 with yearly average growth in this field of 51 articles per year. The USA, United Kingdom (UK), France, Canada, New Zealand, Germany, Australia, China, Turkey and Japan accounted for 449 (75.6%) of all the publications. The total number of citations for all documents was 9,333, with an average of 15.7 citations per document. The h-index of the retrieved documents for lipid emulsion research as antidote for the treatment of acute poisoning was 49. The USA and the UK achieved the highest h-indices, 34 and 14, respectively. New Zealand produced the greatest number of documents with international collaboration (51.9%) followed by Australia (50%) and Canada (41.4%) out of the total number of publications for each country. In summary, we found an increase in the number of publications in the field of lipid emulsion after 2006. The results of this study demonstrate that the majority of publications in the field of lipid emulsion were published by high-income countries. Researchers from institutions in the USA led scientific production on lipid emulsion research. There is an obvious need to promote a deeper engagement through international collaborative research projects and funding mechanisms.

Selective Serotonin-norepinephrine Reuptake Inhibitors-induced Takotsubo Cardiomyopathy

CONTEXT

Takotsubo translates to "octopus pot" in Japanese. Takotsubo cardiomyopathy (TTC) is characterized by a transient regional systolic dysfunction of the left ventricle. Catecholamine excess is the one most studied and favored theories explaining the pathophysiology of TTC.

CASE REPORT

We present the case of a 52-year-old Hispanic female admitted for venlafaxine-induced TTC with a review literature on all the cases of Serotonin-norepinephrine reuptake inhibitors (SNRI)-associated TTC published so far.

CONCLUSION

SNRI inhibit the reuptake of catecholamines into the presynaptic neuron, resulting in a net gain in the concentration of epinephrine and serotonin in the neuronal synapses and causing iatrogenic catecholamine excess, ultimately leading to TTC.

The Use of Fluoxetine in a Patient With Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy is an acute coronary syndrome that is believed to be brought on by stress. Symptoms, which are similar to an acute myocardial infarction, include chest pain, shortness of breath, arrhythmias, and cardiogenic shock, and the electrocardiogram often shows ST and T wave changes. Left ventricular wall hypokinesis along with a significantly reduced ejection fraction are seen on echocardiogram. The great majority of these symptoms all occur in the absence of occlusive disease. Many cases have been reported in which the development of takotsubo cardiomyopathy was associated with serotonin norepinephrine reuptake inhibitors and tricyclic antidepressants. However, no cases of takotsubo cardiomyopathy have been reported involving selective serotonin reuptake inhibitors. This article presents the case of a 51-year-old woman receiving stable therapy with fluoxetine who developed takotsubo cardiomyopathy after an acute stress. We also discuss the clinical presentation of takotsubo cardiomyopathy, review possible causes, and discuss the treatment of depressive symptoms in patients who are at increased risk of developing this illness.

Suicidal Intent and Method of Self-Harm: A Large-scale Study of Self-Harm Patients Presenting to a General Hospital

Data from the Oxford Monitoring System for Attempted Suicide (2004-2011) were used to study hospital presentations for self-harm in which Suicidal Intent Scale (SIS) scores were obtained (N = 4,840). Regression of medians was used to control for the confounding effect of age and gender. Higher estimated median SIS scores were associated with increasing age, male gender, self-poisoning versus self-injury, multiple methods of self-harm versus self-injury alone, use of gas (mainly carbon monoxide), dangerous methods of self-injury (including hanging, gunshot), and use of alcohol as part of the act. For self-poisoning patients, there was a correlation between the number of tablets taken and the total SIS score. Compared with self-poisoning with paracetamol and paracetamol-containing compounds, self-poisoning with antipsychotics was associated with a lower median SIS score while antidepressants had the same estimated median as paracetamol. Use of alcohol within 6 hours of self-harm was associated with lower SIS scores. In conclusion, certain methods of self-harm, particularly dangerous methods of self-injury and self-poisoning with gas, were associated with high intent and should alert clinicians to potential higher risk of suicide. However, apart from use of gas, suicidal intent cannot be inferred from type of drugs used for self-poisoning.

An 11-year retrospective review of venlafaxine ingestion in children from the California Poison Control System

Venlafaxine is commonly used in the United States for approved and non-Food and Drug Administration-approved indications in adults. It is used off-label to treat children for psychiatric diagnoses. The aim of the study was to describe venlafaxine toxicities in children and to identify the venlafaxine dose per weight that correlates with toxicities. An 11-year retrospective study of venlafaxine ingestion in children was performed using the California Poison Control System (CPCS) database. Data was extracted from phone calls received by CPCS clinicians and follow-up phone calls made to assess the patient's progress in a health-care setting. Inclusion criteria were venlafaxine ingestion cases reported to CPCS between January 2001 and December 2011, children aged 20 years and under, venlafaxine as the only ingested substance, managed in a health-care facility, and followed to a known outcome. Two hundred sixty-two cases met the study criteria. Common presentations included gastrointestinal (14.9%), altered mental status (13.7%), and tachycardia (13.4%). The majority of the cases resulted in no effect (51.5%) or minor effect (19.9%). The average estimated dose per weight was 18.3 mg/kg in all patients and 64.5 mg/kg in those experiencing moderate-to-severe adverse effects. Seizures occurred in only 4 of the 262 cases at doses ranging from 1500 to 7500 mg. Although the estimated dose per weight exceeded 10 mg/kg for the majority of the cases, only 12 cases resulted in moderate or severe outcomes. The majority of venlafaxine ingestion cases in children resulted in either no clinical effects or minor clinical effects.

Impact of Age and Sex on QT Prolongation in Patients Receiving Psychotropics

OBJECTIVE

To assess older age and female sex, 2 of the major risk factors for potentially fatal cardiac arrhythmias or sudden cardiac death in patients prescribed psychotropics, within the context of electrocardiographic evidence of time between start of Q wave and end of T wave (QT) interval prolongation, which is an indicator of an increased risk for potentially fatal cardiac arrhythmias.

METHOD

The literature on the relation between age, sex, and QT interval with respect to psychotropic drugs was reviewed.

RESULTS

The QT interval must be corrected (QTc) for heart rate. Because slower heart rates prolong and faster heart rates shorten the QT interval, people with faster heart rates may have a prolonged QT interval that is not apparent until the correction is performed. QTc values for apparently healthy post-pubertal people are less than 450 ms for males and less than 470 ms for females. The longer QT intervals in women may account for their increased risk of potentially fatal cardiac arrhythmias on psychotropics. QTc increases with increasing age. Assessment of QTc in older people is especially important to identify people with a longer QTc who are more likely to attain a serious QT level with drugs that prolong QTc. The age-related increase in QTc is more evident in men than women, suggesting that male sex does not afford protection against potentially fatal arrhythmias at older age.

CONCLUSION

The association of increasing age and female sex with greater QT intervals indicates the need to have an increased awareness of the QTc prior to use of these psychotropics and to evaluate the QTc after initiation of therapy.

Ventricular dysrhythmias associated with poisoning and drug overdose: a 10-year review of statewide poison control center data from California

BACKGROUND

Ventricular dysrhythmias are a serious consequence associated with drug overdose and chemical poisoning. The risk factors for the type of ventricular dysrhythmia and the outcomes by drug class are not well documented.

OBJECTIVE

The aim of this study was to determine the most common drugs and chemicals associated with ventricular dysrhythmias and their outcomes.

METHODS

We reviewed all human exposures reported to a statewide poison control system between 2002 and 2011 that had a documented ventricular dysrhythmia. Cases were differentiated into two groups by type of arrhythmia: (1) ventricular fibrillation and/or tachycardia (VT/VF); and (2) torsade de pointes (TdP).

RESULTS

Among the 300 potential cases identified, 148 cases met the inclusion criteria. Of these, 132 cases (89%) experienced an episode of VT or VF, while the remaining 16 cases (11%) had an episode of TdP. The most commonly involved therapeutic classes of drugs associated with VT/VF were antidepressants (33/132, 25%), stimulants (33/132, 25%), and diphenhydramine (16/132, 12.1%). Those associated with TdP were antidepressants (4/16, 25%), methadone (4/16, 25%), and antiarrhythmics (3/16, 18.75%). Drug exposures with the greatest risk of death in association with VT/VF were antidepressant exposure [odds ratio (OR) 1.71; 95% confidence interval (CI) 0.705-4.181] and antiarrhythmic exposure (OR 1.75; 95% CI 0.304-10.05), but neither association was statistically significant. Drug exposures with a statistically significant risk for TdP included methadone and antiarrhythmic drugs.

CONCLUSIONS

Antidepressants and stimulants were the most common drugs associated with ventricular dysrhythmias. Patients with suspected poisonings by medications with a high risk of ventricular dysrhythmia warrant prompt ECG monitoring.

Risk of QT/QTc Prolongation Among Newer Non-SSRI Antidepressants

Objective: To review QT prolongation potential with newer nonselective serotonin reuptake inhibitor (non-SSRI) antidepressants. Data Sources: A PubMed literature search was performed from 1982 through June 16, 2014. Search terms included bupropion, desvenlafaxine, duloxetine, levomilnacipran, mirtazapine, venlafaxine, and vilazodone in combination with each of the following terms: cardiac toxicity, QTc prolongation, QT prolongation, torsades de pointes, and TdP. Study Selection and Data Extraction: English-language human studies, case reports, package inserts, manufacturer electronic communications, and ArizonaCert database were utilized. Data Synthesis: Rare QT prolongation has been reported with venlafaxine at therapeutic doses and in overdose. Bupropion has also been linked to QT prolongation in overdose situations. In elderly patients with a variety of high-risk comorbidities, mirtazapine did demonstrate higher odds of sudden cardiac death and ventricular arrhythmias when compared with paroxetine. Largely because of a lack of available data, existing studies fail to demonstrate QT prolongation with desvenlafaxine, duloxetine, levomilnacipran, and vilazodone. Conclusion: Based on the current literature, risk of QT/QTc prolongation with the majority of newer non-SSRI antidepressants at therapeutic doses is low. The highest risk for QT prolongation appears to exist in overdose situations with venlafaxine and bupropion. Given the few to nonexistent controlled studies and confounding variables present in case reports, it is difficult to draw conclusions on QT prolongation risk with many of the newer non-SSRI antidepressants.

Drug induced QT prolongation: the measurement and assessment of the QT interval in clinical practice

There has been an increasing focus on drug induced QT prolongation including research on drug development and QT prolongation, following the removal of drugs due to torsades de pointes (TdP). Although this has improved our understanding of drug-induced QT prolongation there has been much less research aimed at helping clinicians assess risk in individual patients with drug induced QT prolongation. This review will focus on assessment of drug-induced QT prolongation in clinical practice using a simple risk assessment approach. Accurate measurement of the QT interval is best done manually, and not using the measurement of standard ECG machines. Correction for heart rate (HR) using correction formulae such as Bazett's is often inaccurate. These formulae underestimate and overestimate the duration of cardiac repolarization at low and high heart rates, respectively. Numerous cut-offs have been suggested as an indicator of an abnormal QT, but are problematic in clinical practice. An alternative approach is the QT nomogram which is a plot of QT vs. HR. The nomogram has an 'at risk' line and QT-HR pairs above this line have been shown in a systematic study to be associated with TdP and the line is more sensitive and specific than Bazett's QTc of 440 ms or 500 ms. Plotting the QT-HR pair for patients on drugs suspected or known to cause QT prolongation allows assessment of the QT interval based on normal population QT variability. This risk assessment then allows the safer commencement of drugs therapeutically or management of drug induced effects in overdose.

Changes in cardiovascular function after venlafaxine but not pregabalin in healthy volunteers: a double-blind, placebo-controlled study of orthostatic challenge, blood pressure and heart rate

It is generally thought that venlafaxine raises blood pressure at higher doses; however, some studies have found no effect or a decrease in blood pressure. The aim of this study was to evaluate the cardiovascular (CV) effects of 3 weeks of dosing with venlafaxine, pregabalin and placebo on young healthy adults. Fifty-four participants, of mean age 23.1 years (sd 4.68), 29 male, were randomised into three parallel groups. Each group received one of the three drugs, dosed incrementally over a 3-week period to reach daily doses of 150 mg/day venlafaxine and 200 mg/day pregabalin. Blood pressure sphygmomanometer measurements, heart rate measurements, and orthostatic challenges recorded continuously beat-to-beat were performed weekly over this period and 5 days after treatment cessation. Results showed resting systolic blood pressure (SBP) and resting and standing diastolic blood pressure (DBP) and heart rate (HR) were significantly raised by venlafaxine compared with the pregabalin and placebo groups. SBP drop on standing was larger, the resulting overshoot was smaller, and recovery was slower on venlafaxine. HR recovery was significantly impaired by venlafaxine. CV changes were observed after only 1 week of dosing at 112.5 mg/day. These effects of venlafaxine are likely to be due to its action of noradrenergic reuptake inhibition.

Cardiovascular considerations in antidepressant therapy: an evidence-based review

There is a definite correlation between cardiovascular diseases and depressive disorders. Nevertheless, many aspects of this association have yet to be fully elucidated. Up to half of coronary artery disease patients are liable to suffer from some depressive symptoms, with approximately 20% receiving a diagnosis of major depressive disorders. Pharmacotherapy is a key factor in the management of major depression, not least in patients with chronic diseases who are likely to fail to show proper compliance and response to non-pharmacological interventions. Antidepressants are not deemed completely safe. Indeed, numerous side effects have been reported with the administration of antidepressants, among which cardiovascular adverse events are of paramount importance owing to their disabling and life-threatening nature. We aimed to re-examine some of the salient issues in antidepressant therapy vis-à-vis cardiovascular considerations, which should be taken into account when prescribing such medications.

STEPS for cost-effective prescribing of serotonin-norepinephrine reuptake inhibitors (SNRIs) in major depressive disorder: Focus on venlafaxine (Effexor®) versus duloxetine (Cymbalta®)

Selection of an antidepressant medication is based on various factors, such as safety, tolerability, and cost. This article reviews the cost-effectiveness of the different serotonin-norepinephrine reuptake inhibitors (SNRIs).

A review of the suitability of duloxetine and venlafaxine for use in patients with depression in primary care with a focus on cardiovascular safety, suicide and mortality due to antidepressant overdose

Depression and anxiety disorders are among the most common disorders treated by general practitioners (GPs) in the UK. Since both disorders are associated with a significantly increased risk of suicide, including with antidepressant overdose, the safety of antidepressants in overdose is of paramount importance. Numerous updates relating to antidepressant safety have been issued by regulators in the UK which may have eroded GP confidence in antidepressants. Venlafaxine, a serotonin nor adrenaline reuptake inhibitor (SNRI) had primary care prescribing restrictions placed on it in 2004 due to concerns about cardiotoxicity and mortality in overdose. Although a review of the evidence led to a reversal of the majority of restrictions in 2006, evidence suggests GPs may still be cautious in their prescribing of venlafaxine and possibly other SNRI antidepressants for patients with depression and anxiety disorders. This paper reviews the evidence pertaining to the safety of SNRI antidepressants from a perspective of cardiovascular safety and overdose. The currently available evidence suggests a marginally higher toxicity of venlafaxine in overdose compared with another SNRI duloxetine and the selective serotonin reuptake inhibitors (SSRIs), although this may be related to differential patterns of prescribing in high-risk patients. Based on this review SNRIs have a positive risk benefit profile in the treatment of depression and generalized anxiety disorder in primary care, especially as second-line agents to SSRIs.

Intravenous lipid administration for drug-induced toxicity: a critical review of the existing data

Following the discovery that administration of intravenous lipid emulsion (ILE) may reverse the cardiac and neurological toxicity of certain local anesthetic agents, ILE's potential role has recently been explored in the setting of toxicity attributed to a variety of different drugs. The potential mechanisms, safety and efficacy of this approach are considered in this review. Data are reviewed from 76 published reports involving ILE administration for severe drug toxicity, including 55 where toxicity was due to nonanesthetic agents. ILE was reported to exert a positive therapeutic effect in only a proportion of the reported cases, with greatest evidence of efficacy concerning local anesthetic agents. Administration has typically involved bolus administration followed by continuous maintenance infusion, and a number of different mechanisms are proposed, from preferential partitioning of the drug from cardiac tissue to the circulating lipid fraction and direct inotropic effects related to carnitine pathways and fatty acid oxidative metabolism. No major adverse effects have been encountered, but too few data exist to adequately address the safety profile of ILE.