Venlafaxine extended-release: a review of its use in the management of major depression

Green innovation in analytical chemistry: A sustainable densitometric HPTLC approach for the distinctive separation and quantification of structurally related abused drugs - tramadol, tapentadol, and venlafaxine - in seized pharmaceutical dosage forms

An innovative ecofriendly high-performance thin layer chromatographic (HPTLC) method with spectrophotometric detection for simultaneous determination of Tramadol (TMD), Tapentadol (TAP), and Venlafaxine (VEN) in seized dosage forms was presented. Our method was conducted to achieve separation following the optimal conditions: pre-coated silica gel plates using a green mobile phase (heptane: acetone: ammonia, 7:3:0.5 v/v), with absorbance scanning at 272 nm. The validation of the method was done following International Conference on Harmonization (ICH) guidelines, demonstrates linearity, accuracy, precision, selectivity, robustness, and system suitability. Separation was achieved with a detection limit of 0.34, 0.16, and 0.084 (ug/band) for TMD, TAP, and VEN, respectively, the method successfully analyzes seized samples. Trueness is confirmed through a high degree of similarity between HPTLC and gas chromatography results. The study's ecofriendly approach, simplicity, and selectivity position it as a promising method for efficient, on-site monitoring of seized samples.

Non-inferiority of intermittent theta burst stimulation over the left V1 vs. classical target for depression: A randomized, double-blind trial

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) targeting the visual cortex (VC) has shown antidepressant effects for major depressive disorder (MDD) in sham-controlled trials, but comparisons with rTMS targeting the left dorsolateral prefrontal cortex (DLPFC) are lacking. We aimed to determine the non-inferiority of intermittent theta-burst stimulation (iTBS) over VC vs DLPFC for MDD.

METHODS

Participants randomly received navigated iTBS over the left V1 or the left DLPFC twice daily for 14 days with a 3-month follow-up. The primary outcome was change in Hamilton Depression Rating Scale (HAMD-17) score from baseline to treatment end, with 2.5 points as the non-inferiority margin. Secondary outcomes included: improvement in Montgomery-Asberg Depression Rating Scale (MADRS), Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA); response and remission rates; suicidal ideation and adverse events.

RESULTS

Of 75 randomized patients, 67 completed full treatment, including 52 first-episode patients and 15 relapsers. The primary outcome indicated the non-inferiority of VC (adjusted difference 1.14, lower 97.5 % CI -1.24; p = .002), confirmed by improvements in objective cognitive task and protein levels, as did most secondary outcomes. Reduced suicidal ideation after treatment, incidence of eye discomfort and pain score were lower in the VC group.

CONCLUSIONS

Left VC iTBS has the potential to be non-inferior to DLPFC iTBS in most first-episode MDD in improving depressive symptoms and cognitive function, with less suicidal ideation and adverse events.

LIMITATIONS

Given the limited sample size, the lack of a sham control and the use of antidepressants, the findings should be interpreted with caution.

Dose-related hypoglycemia in venlafaxine poisoning: a retrospective cohort study

CONTEXT

Several case reports describe hypoglycemia in the context of venlafaxine overdose, while investigations at therapeutic dose suggested a neutral effect on glucose homeostasis. Studies on hypoglycemia in venlafaxine intoxication are lacking.

METHODS

Single-center retrospective cohort study of non-diabetic patients presenting with a laboratory-confirmed antidepressant overdose to the department of clinical toxicology of a tertiary care hospital over a 12-year period. Our main goal was to investigate the association of hypoglycemia as the primary outcome with venlafaxine exposure using multiple logistic regression. Multi-drug exposures were included. We further aimed to describe the association of blood glucose (BG)/hypoglycemia with antidepressant dose, seizures and length of hospital stay.

RESULTS

525 antidepressant intoxications were included, 85 of which involved venlafaxine. Hypoglycemia occurred in 34.1% (29/85) of venlafaxine intoxications and in 10.7% (47/440) of non-venlafaxine antidepressant overdoses. Venlafaxine exposure was significantly associated with hypoglycemia (adjusted odds ratio (OR): 6.6, 95% confidence interval (CI): 3.5-12.6). Venlafaxine-associated hypoglycemia was mainly mild (BG: 51-70 mg/dL), in 75.8% of cases, to moderate (BG: 31-50 mg/dL), in 20.7%, with one case of severe hypoglycemia (BG: 30 mg/dL). BG was significantly inversely correlated with dose in the venlafaxine group (Spearman's correlation coefficient: -0.47, p = 0.002) but not in other commonly prescribed antidepressants. Regardless of venlafaxine exposure, hypoglycemia was associated with seizures (adjusted OR: 5.3, 95% CI: 2.6-10.6) and with a 2.7 day increase in hospital length of stay (95% CI: 1.3-4.2).

CONCLUSION

A dose-related, mild to moderate hypoglycemia occurred in over one-third of venlafaxine poisonings. In overdose of other antidepressants, hypoglycemia was seen less frequently and without significant dose-dependency. Regardless of venlafaxine exposure, hypoglycemia was associated with seizures and prolonged length of stay, although these factors are likely primarily determined by other toxicities. BG monitoring in venlafaxine overdose should be considered.

Consensus of the Brazilian Headache Society (SBCe) for prophylactic treatment of episodic migraine: part II

BACKGROUND

Migraine affects 1 billion people worldwide and > 30 million Brazilians; besides, it is an underdiagnosed and undertreated disorder.

OBJECTIVE

The need to disseminate knowledge about the prophylactic treatment of migraine is known, so the Brazilian Headache Society (SBCe, in the Portuguese acronym) appointed a committee of authors with the objective of establishing a consensus with recommendations on the prophylactic treatment of episodic migraine based on articles from the world literature as well as from personal experience.

METHODS

Meetings were held entirely online, with the participation of 12 groups that reviewed and wrote about the pharmacological categories of drugs and, at the end, met to read and finish the document. The drug classes studied in part II of this Consensus were: antihypertensives, selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, calcium channel blockers, other drugs, and rational polytherapy.

RESULTS

From this list of drugs, only candesartan has been established as effective in controlling episodic migraine. Flunarizine, venlafaxine, duloxetine, and pizotifen were defined as likely to be effective, while lisinopril, enalapril, escitalopram, fluvoxamine, quetiapine, atorvastatin, simvastatin, cyproheptadine, and melatonin were possibly effective in prophylaxis of the disease.

CONCLUSIONS

Despite an effort by the scientific community to find really effective drugs in the treatment of migraine, given the large number of drugs tested for this purpose, we still have few therapeutic options.

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.

Transdermal Route: A Viable Option for Systemic Delivery of Antidepressants

The high rise in the population suffering from depression depicts the need for improved and highly effective treatment options for this condition. Efforts to develop existing drugs into user-friendly dosage forms with a number of advantages in major depressive states, including but not limited to: sustained drug release, reduced drug dosing frequency, improved tolerance and adherence, suitability for use in diverse populations and different treatment scenarios, as well as less central nervous system side effects are required. One such non-invasive drug delivery route that could provide the aforementioned benefits in the treatment of depression is the transdermal route. A number of conventional and emerging transdermal delivery strategies have been investigated for some potent antidepressants and results depict the potential of this route as a viable means for systemic delivery of therapeutically relevant doses of the tested agents, with Emsam®, the commercially available patch of selegiline, being an evidence for the same. The investigated approaches include the formulation of transdermal patches, use of vesicular drug carriers, pro-drug approach, microemulsification, chemical as well as physical enhancement technologies. This review provides a comprehensive account of the rationale, developments made till date, scope and future prospects of delivering antidepressants via the transdermal1 route of administration.

Intrinsic reward circuit connectivity profiles underlying symptom and quality of life outcomes following antidepressant medication: a report from the iSPOT-D trial

There is a critical need to better understand the neural basis of antidepressant medication (ADM) response with respect to both symptom alleviation and quality of life (QoL) in major depressive disorder (MDD). Reward neurocircuitry has been implicated in QoL, the neural basis of MDD, and the mechanisms of ADM response. Yet, we do not know whether change in reward neurocircuitry as a function of ADM is associated with change in symptoms and QoL. To address this gap in knowledge, we analyzed data from 128 patients with MDD who participated in the iSPOT-D trial and were assessed with functional neuroimaging pre- and post-ADM treatment (randomized to sertraline, venlafaxine-XR, or escitalopram). 58 matched healthy controls were scanned at the same time points. We quantified functional connectivity (FC) of reward neurocircuitry using nucleus accumbens (NAc) seed regions of interest, and then characterized how changes in FC relate to symptom response (primary outcome) and QoL response (secondary outcome). Symptom responders showed an increase in NAc-dorsal anterior cingulate cortex (ACC) FC relative to non-responders (p < 0.001) which was associated with improvement in physical QoL (p < 0.0003), and a decrease in NAc-inferior parietal lobule FC relative to controls (p < 0.001). QoL response was characterized by increases in FC between NAc-ventral ACC for environmental, NAc-thalamus for physical, and NAc-paracingulate gyrus for social domains (p < 0.001). Symptom responders to sertraline were distinguished by a decrease in NAc-insula FC (p < 0.001) and to venlafaxine-XR by an increase in NAc-inferior temporal gyrus FC (p < 0.005). Findings suggest that change in reward neurocircuitry may underlie differential ADM response profiles with respect to symptoms and QoL in depression.

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.

Connectivity of the Cognitive Control Network During Response Inhibition as a Predictive and Response Biomarker in Major Depression: Evidence From a Randomized Clinical Trial

BACKGROUND

In treating major depressive disorder, we lack tests anchored in neurobiology that predict antidepressant efficacy. Cognitive impairments are a particularly disabling feature of major depressive disorder. We tested whether functional connectivity during a response-inhibition task can predict response to antidepressants and whether its changes over time are correlated to symptom changes.

METHODS

We analyzed data from outpatients with major depressive disorder (n = 124) randomized to receive escitalopram, sertraline, or venlafaxine (8 weeks) and healthy control subjects (n = 59; age 18-65 years). Before and after treatment, participants were interviewed and scanned using functional magnetic resonance imaging, and functional connectivity was measured using generalized psychophysiological interaction during response inhibition (Go-NoGo task). We investigated the interaction between treatment type and response (≥50% reduction on self-reported symptoms), coupling differences between responders and nonresponders at baseline, their correlation with symptom improvement, and their changes in time.

RESULTS

During response inhibition, connectivity between the dorsolateral prefrontal cortex/supramarginal gyrus and supramarginal gyrus/middle temporal gyrus was associated with response to sertraline and venlafaxine, but not escitalopram. Sertraline responders had higher functional connectivity between these regions compared with nonresponders, whereas venlafaxine responders had lower functional connectivity. For sertraline, attenuation of connectivity in the precentral and superior temporal gyri correlated with posttreatment symptom improvement. For venlafaxine, enhancement of connectivity between the orbitofrontal cortex and subcortical regions correlated with symptom improvement.

CONCLUSIONS

Connectivity of the cognitive control circuit during response inhibition selectively and differentially predicts antidepressant treatment response and correlates with symptom improvement. These quantitative markers tied to the neurobiology of cognitive features of depression could be used translationally to predict and evaluate treatment response.

Study of mental health outcomes associated with different brands of venlafaxine at the Kumeu medical centre from January 2017 to October 2018

BACKGROUND

The antidepressant venlafaxine has been available in New Zealand for two decades and is funded by the New Zealand Drug Purchasing Agency PHARMAC. This audit aimed to determine whether change to a different funded generic formulation of venlafaxine affected patient responses to venlafaxine.

METHODS

A retrospective review of patient records for all patients at Kumeu Medical Centre, Auckland, New Zealand who received a prescription for venlafaxine since January 2017 was performed. Outcomes for patients who had experienced a stable positive clinical response to either of the two previously funded venlafaxine formulations and who were switched to the newly funded formulation were summarised.

RESULTS

Of 49 patients who had been prescribed venlafaxine, 34 patients were excluded; 15 patients had experienced a stable positive clinical response to either of the two previously funded venlafaxine formulations and switched to the newly funded formulation. Of these, 12 (80%) had poor outcomes following the change in venlafaxine formulation. Nine patients switched back to the original brand venlafaxine and showed improvement in clinical symptoms.

CONCLUSION

These cases, reported from a single general practice, should be sufficient to call attention to the possibility of loss of effectiveness for patients treated with a funded generic brand of venlafaxine, and the need for further research.

Psychiatric Medication Use and Weight Outcomes One Year After Bariatric Surgery

BACKGROUND

Given the high rates of psychiatric comorbidity in bariatric surgery patients, pharmacotherapy is common and could potentially influence weight loss outcomes.

OBJECTIVE

We aimed to identify the impact of psychotropic medication use on percent total weight loss (%TWL) 1 year after bariatric surgery.

METHODS

In this prospective cohort study, 190 patients were compared based on demographic variables (age, sex, relationship status, employment status), body mass index, %TWL, and psychotropic medication use before and 1 year after bariatric surgery. An analysis of variance test was used as a global test of significance for psychotropic medication comparisons related to %TWL. Significance of post hoc comparisons was calculated with the Tukey's Honestly Significance Difference test.

RESULTS

Sixty-one of 190 (32.1%) patients were taking psychiatric medications before surgery; of those, 82% (50/61) continued to take psychiatric medications 1-year after surgery. %TWL did not significantly differ between patients taking no psychiatric medications, one medication, or more than one medication 1 year after surgery (31.4% vs. 29.9% vs. 34.4%, respectively). Among patients taking antidepressants, those taking serotonin-norepinephrine reuptake inhibitors had a significantly higher %TWL than those taking selective serotonin reuptake inhibitors (36.4% vs. 27.8%; P = 0.032).

CONCLUSION

This longitudinal study suggests that psychiatric medication use was not associated with poorer %TWL at 1 year after bariatric surgery. Within class, antidepressant use may have differential effects on weight loss after bariatric surgery and warrants further investigation.

CYP2D1 Gene Knockout Reduces the Metabolism and Efficacy of Venlafaxine in Rats

Rat CYP2D1 has been considered as an ortholog of human CYP2D6 To assess the role of CYP2D1 in physiologic processes and drug metabolism, a CYP2D1-null rat model was generated with a CRISPR/Cas9 method. Seven base pairs were deleted from exon 4 of CYP2D1 of Sprague-Dawley wild-type (WT) rats. The CYP2D1-null rats were viable and showed no abnormalities in general appearance and behavior. The metabolism of venlafaxine (VLF) was further studied in CYP2D1-null rats. The V _max and intrinsic clearance of the liver microsomes in vitro from CYP2D1-null rats were decreased (by ∼46% and ∼57% in males and ∼47% and ∼58% in females, respectively), while the Michaelis constant was increased (by ∼24% in males and ∼25% in females) compared with WT rats. In the pharmacokinetic studies, compared with WT rats, VLF in CYP2D1-null rats had significantly lower apparent total clearance and apparent volume of distribution (decreased by ∼36% and ∼48% in males and ∼23% and ∼25% in females, respectively), significantly increased area under the curve (AUC) from the time of administration to the last time point, AUC from the start of administration to the theoretical extrapolation, and C _max (increased by ∼64%, ∼59%, and ∼26% in males and ∼43%, ∼35%, and ∼15% in females, respectively). In addition, O-desmethyl venlafaxine formation was reduced as well in CYP2D1-null rats compared with that in WT rats. Rat depression models were developed with CYP2D1-null and WT rats by feeding them separately and exposing them to chronic mild stimulation. VLF showed better efficacy in the WT depression rats compared with that in the CYP2D1-null rats. In conclusion, a CYP2D1-null rat model was successfully generated, and CYP2D1 was found to play a certain role in the metabolism and efficacy of venlafaxine. SIGNIFICANCE STATEMENT: A novel CYP2D1-null rat model was generated using CRISPR/Cas9 technology, and it was found to be a valuable tool in the study of the in vivo function of human CYP2D6. Moreover, our data suggest that the reduced O-desmethyl venlafaxine formation was associated with a lower VLF efficacy in rats.

Medications for alcohol use disorders: An overview

Patients who suffer from alcohol use disorders (AUDs) usually go through various socio-behavioral and pathophysiological changes that take place in the brain and other organs. Recently, consumption of unhealthy food and excess alcohol along with a sedentary lifestyle has become a norm in both developed and developing countries. Despite the beneficial effects of moderate alcohol consumption, chronic and/or excessive alcohol intake is reported to negatively affect the brain, liver and other organs, resulting in cell death, organ damage/failure and death. The most effective therapy for alcoholism and alcohol related comorbidities is alcohol abstinence, however, chronic alcoholic patients cannot stop drinking alcohol. Therefore, targeted therapies are urgently needed to treat such populations. Patients who suffer from alcoholism and/or alcohol abuse experience harmful effects and changes that occur in the brain and other organs. Upon stopping alcohol consumption, alcoholic patients experience acute withdrawal symptoms followed by a protracted abstinence syndrome resulting in the risk of relapse to heavy drinking. For the past few decades, several drugs have been available for the treatment of AUDs. These drugs include medications to reduce or stop severe alcohol withdrawal symptoms during alcohol detoxification as well as recovery medications to reduce alcohol craving and support abstinence. However, there is no drug that completely antagonizes the adverse effects of excessive amounts of alcohol. This review summarizes the drugs which are available and approved by the FDA and their mechanisms of action as well as the medications that are under various phases of preclinical and clinical trials. In addition, the repurposing of the FDA approved drugs, such as anticonvulsants, antipsychotics, antidepressants and other medications, to prevent alcoholism and treat AUDs and their potential target mechanisms are summarized.

Exploring venlafaxine pharmacokinetic variability with a phenotyping approach, a multicentric french-swiss study (MARVEL study)

Background

It is well known that the standard doses of a given drug may not have equivalent effects in all patients. To date, the management of depression remains mainly empirical and often poorly evaluated. The development of a personalized medicine in psychiatry may reduce treatment failure, intolerance or resistance, and hence the burden and costs of mood depressive disorders.

The Geneva Cocktail Phenotypic approach presents several advantages including the “in vivo” measure of different cytochromes and transporter P-gp activities, their simultaneous determination in a single test, avoiding the influence of variability over time on phenotyping results, the administration of low dose substrates, a limited sampling strategy with an analytical method developed on DBS analysis.

The goal of this project is to explore the relationship between the activity of drug-metabolizing enzymes (DME), assessed by a phenotypic approach, and the concentrations of Venlafaxine (VLX) + O-demethyl-venlafaxine (ODV), the efficacy and tolerance of VLX.

Methods/design

This study is a multicentre prospective non-randomized open trial. Eligible patients present a major depressive episode, MADRS over or equal to 20, treatment with VLX regardless of the dose during at least 4 weeks. The Phenotype Visit includes VLX and ODV concentration measurement.

Following the oral absorption of low doses of omeprazole, midazolam, dextromethorphan, and fexofenadine, drug metabolizing enzymes activity is assessed by specific metabolite/probe concentration ratios from a sample taken 2 h after cocktail administration for CYP2C19, CYP3A4, CYP2D6; and by the determination of the limited area under the curve from the capillary blood samples taken 2–3 and 6 h after cocktail administration for CYP2C19 and P-gp.

Two follow-up visits will take place between 25 and 40 days and 50–70 days after inclusion. They include assessment of efficacy, tolerance and observance.

Eleven french centres are involved in recruitment, expected to be completed within approximately 2 years with 205 patients. Metabolic ratios are determined in Geneva, Switzerland.

Discussion

By showing an association between drug metabolism and VLX concentrations, efficacy and tolerance, there is a hope that testing drug metabolism pathways with a phenotypical approach would help physicians in selecting and dosing antidepressants. The MARVEL study will provide an important contribution to increasing the knowledge of VLX variability and in optimizing the use of methods of personalized therapy in psychiatric settings.

Trial registration

ClinicalTrials.govNCT02590185 (10/27/2015). This study is currently recruiting participants.

Adverse Drug Reactions in the Orofacial Region

A wide spectrum of drugs can sometimes give rise to numerous adverse orofacial manifestations, particularly dry mouth, taste disturbances, oral mucosal ulceration, and/or gingival swelling. There are few relevant randomized double-blind controlled studies in this field, and therefore this paper reviews the data from case reports, small series, and non-peer-reviewed reports of adverse drug reactions affecting the orofacial region (available from a MEDLINE search to April, 2003). The more common and significant adverse orofacial consequences of drug therapy are discussed.

A Randomized, Double-Blind, Placebo-Controlled Study of Venlafaxine XR in Out-Patients With Tension-Type Headache

The aim of this study was to evaluate in a double-blind, randomized, placebo-controlled study the safety and efficacy of venlafaxine extended release (XR) in the prophylactic treatment of out-patients with tension-type headache (TTH) and no current depression or anxiety disorders. Sixty neurology and headache clinic out-patients meeting the International Headache Society diagnostic criteria for TTH were treated with venlafaxine XR (150 mg/day, n = 34) or placebo ( n = 26) for 12 weeks. The primary efficacy variable was the decline in number of days with headache. At end-point, the venlafaxine XR group had a significantly greater decrease in the number of days with headache compared with placebo ( P = 0.05). Differences with regard to secondary efficacy variables where not significant. The number needed to treat for responders (≥50% reduction in days with headache) was 3.48. Six patients in the venlafaxine XR group interrupted therapy due to adverse events, while no patients in the placebo group did so for the same reason. The number needed to harm was 5.58. This study provides preliminary evidence for the efficacy and safety of venlafaxine XR 150 mg/day in reducing the number of days with TTH.

Preventive Treatment of Migraine: Effect on Weight

Weight gain is a side-effect commonly associated with drugs used for headache prophylaxis. Weight gain can adversely affect patient health, exacerbate comorbid metabolic disorders and encourage noncompliance. Few studies have been conducted specifically on the effect of headache medications on weight, and it is important for physicians to have accurate information about weight-gain side-effects when identifying appropriate pharmacological regimens. This review discusses the potential effects on weight of the more common headache medications.

Alleviation of pain in painful diabetic neuropathy

INTRODUCTION

Painful diabetic neuropathy (PDN) is a disabling pain condition. Its pathomechanism remains unknown, but a sensitization and neuronal hyperexcitabilty have been suggested. Only symptomatic pharmacological pain management treatment is currently available.

AREAS COVERED

The origin of PDN is enigmatic, and the evidence-based therapeutic guidelines therefore consist only of antidepressants and antiepileptics as first-line recommended drugs. This article relates to a MEDLINE/PubMed systematic search (2005-2015).

EXPERT OPINION

The results of the meta-analysis from the aspect of the efficacy of amitriptyline, duloxetine, venlafaxine, gabapentin and pregabalin are favorable, but the placebo response rate is relatively high in patients with neuropathic pain. For personalization of the medication of PDN patients, the optimum dosing, the genotyping of the metabolizing enzymes and optimum biomarkers are needed. As concerns the future perspectives, specific sodium channel subtype inhibitors acting on peripheral nociceptive neurons or modified T-type voltage-gated calcium channel blockers may be promising targets for pharmaceutical innovations. Another attractive strategy for the treatment is based on the effects of monoclonal antibodies against nerve growth factor, sodium channels, specific receptor and cytokines. Botulinum toxin A, capsaicin patch and spinal cord stimulation therapies are the nearest future therapeutic options for the treatment of PDN patients.

Serotonergic or Anticholinergic Toxidrome: Case Report of a 9-Year-Old Girl

OBJECTIVE

The aim of this study was to report an acute onset of symptoms erroneously attributed to serotonin syndrome in a child who had been given both anticholinergic and serotonergic agents.

CASE SUMMARY

A 9-year-old girl with chronic anxiety and gastrointestinal problems was prescribed oral sertraline 6.25 mg daily, as well as hyoscyamine, ondansetron, montelukast, and a course of nitazoxanide. She was also routinely given diphenhydramine and omeprazole. Three days after increasing sertraline to 12.5 mg, she presented to the emergency department with altered mental status, hallucinations, mydriasis, tachycardia, and pyrexia. She was admitted to the pediatric intensive care unit and subsequently treated unsuccessfully for serotonin syndrome, with blurred vision and clonus persisting at discharge 4 days after admittance. Upon follow-up with her outpatient clinic, all anticholinergic agents were discontinued, and symptoms slowly resolved.

CONCLUSIONS

This case illustrates the importance of differential diagnosis between toxidromes and how clinical presentation can be altered by preexisting conditions as well as the use of medications that affect multiple neurotransmitter systems.

Venlafaxine as the 'baby ecstasy'? Literature overview and analysis of web-based misusers' experiences

INTRODUCTION

Venlafaxine is one of the most frequently prescribed antidepressants worldwide, despite its toxicity risk in overdose. Furthermore, the molecule has been recently identified at the EU-wide level as one of the novel psychoactive substances. This paper aims at investigating the potential of misuse, taking into account both the existing literature and the analysis of the misusers' experiences as described in venlafaxine misuse web reports.

METHODS

A literature search was performed using PubMed, Embase, and Medline. Posts/threads relating to venlafaxine misuse issues were identified through Google® and Yahoo® English-language searches. Resulting websites' data were then qualitatively assessed, and information was collected on a range of issues, including dosage, drug intake modalities, untoward drug effects, and association with other recreational drugs.

RESULTS

A few literature case reports focusing on venlafaxine as a misusing drug were here identified. The molecule was here typically ingested or snorted at dosages up to 10-15 times higher than those clinically advised, obtaining MDMA/amphetamine-like stimulant and psychedelic effects. Polydrug misuse was commonly reported. Venlafaxine appeared to be widely available online for sale.

CONCLUSIONS

Physicians should carefully evaluate patients for history of drug dependence and observe them for signs of venlafaxine misuse.

An Evaluation of Health Service Impacts Consequent to Switching from Brand to Generic Venlafaxine in New Zealand under Conditions of Price Neutrality

OBJECTIVE

To study the health impact on adult New Zealand patients who switch from originator brand to generic venlafaxine.

METHODS

The national pharmacy database was used to select patients using venlafaxine for at least 6 months. Switchers and nonswitchers were identified, and switch behavior was compared for a 12-month follow-up period. Change in health service use following switching was also compared between switchers and nonswitchers including use of the emergency department, hospital, and specialist outpatient services over the same period.

RESULTS

Approximately 12% of all originator brand users switched to generic venlafaxine, at least half of whom continued to use the generic throughout the follow-up period to August 1, 2012. Almost 60% of new users of the generic venlafaxine, however, switched to using the originator brand. Aside from a slight reduction in the use of outpatient services among switchers, there were no significant differences in health services use between switchers and nonswitchers for either existing or new venlafaxine users.

CONCLUSIONS

Although both products remain fully subsidized and available, there is little incentive for prescribers, pharmacists, or patients to switch to the less expensive generic brand. If savings to the national New Zealand budget are to be realized, additional policy measures should be implemented to minimize incentives for multiple and reverse switching, and prescribers, as key opinion leaders, could take the lead in promoting generics to their patients.

Venlafaxine pharmacokinetics focused on drug metabolism and potential biomarkers

Venlafaxine (VEN) is one of the safest and most effective drugs used in the treatment of selective serotonin reuptake inhibitors-resistant depression, and thereby it is nowadays one of the most commonly prescribed antidepressants. Nevertheless, patients treated with antidepressant drugs including VEN have exhibited large inter-individual variability in drug outcomes, possibly due to the influence of genetic and nongenetic factors on the drug pharmacokinetics and/or pharmacodynamics. Among them, an increased interest has emerged over the last few years on the genetic and/or phenotypic profile for drug-metabolizing cytochrome P450 isoenzymes and drug transporters such as potential predictive pharmacokinetic-based biomarkers of the variability found in drug biodisposition and antidepressant response. The integration of some of these key therapeutic biomarkers with classic therapeutic drug monitoring constitutes a promising way to individualization of VEN's pharmacotherapy, offering to clinicians the ability to better predict and manage pharmacological treatments to maximize the drug effectiveness. Thus, this review provides an extensive discussion of the pharmacokinetics of VEN focusing in particular on metabolism issues, without forgetting the clinically relevant sources of pharmacokinetics variability (mainly the genetic sources) and aiming on the identification of phenotypic and/or genetic biomarkers for therapy optimization.

Clinical drug-drug interactions: focus on venlafaxine

Venlafaxine (VEN) is an antidepressant agent widely used nowadays as an alternative to selective serotonin reuptake inhibitors (SSRIs), particularly for the treatment of SSRI-resistant depression. As the co-administration of antidepressant drugs with other medications is very common in clinical practice, the potential risk for pharmacokinetic and/or pharmacodynamic drug interactions that may be clinically meaningful increases. Bearing in mind that VEN has exhibited large variability in antidepressant response, besides the individual genetic background, several other factors may contribute to those variable clinical outcomes, such as the occurrence of significant drug-drug interactions. Indeed, the presence of drug interactions is possibly one of the major reasons for interindividual variability, and their anticipation should be considered in conjugation with other specific patients' characteristics to optimize the antidepressant therapy. Hence, a comprehensive overview of the pharmacokinetic- and pharmacodynamic-based drug interactions involving VEN is herein provided, particularly addressing their clinical relevance.

Effect of prenatal administration of venlafaxine on postnatal development of rat offspring

About 3% of pregnant women are treated with antidepressant drugs during gestation. After delivery the number of treated women increases to 5 to 7%. Most prescribed antidepressants in pregnancy are selective serotonin re-uptake inhibitors and/or serotonin and noradrenaline re-uptake inhibitors, such as fluoxetine, paroxetine, sertraline, citalopram and venlafaxine (VENF). Despite the fact that VENF has been assigned to pregnancy category C by the FDA, experimental studies with this drug are rare. The aim of this pilot study was to investigate the effect of prenatal administration of VENF on early postnatal development of rat offspring and selected biochemical variables at weaning of pups. Pregnant female Wistar rats were treated with VENF from day 15 to 20 of gestation at the doses of 7.5, 37.5 and 70 mg/kg. Females were allowed to spontaneously deliver their pups. After delivery the pups were inspected for viability, gross malformation and they were weighed on day 0, 4 and 21 post partum. On day 21 post partum, the pups were killed, brains were removed from the skulls and blood samples were collected for biochemical assay (proteins, glucose-GOD, glucose-HEX, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase and total antioxidant status). The study showed that prenatal VENF administration resulted in a mild maternal intoxication manifested by decreased body weight gain of pregnant females. There was no effect of the drug tested on the body and brain weights of offspring. No obvious morphological alterations were observed in the delivered pups. Similarly, there were no changes in the selected biochemical variables determined.

Contemporary concepts in the pharmacotherapy of depression in older people

Late-life depression is common in older people. Its incidence increases significantly after age 70 to 85, as well as among those living in long-term care facilities. Depression contributes to excess morbidity and complicates management of comorbid conditions in older people. Diagnosis and management of depression often present clinicians with a challenge. Indeed, symptoms of depression in older people may not always be the same as those associated with depression in younger people. Additionally, age-related changes in pharmacokinetics and pharmacodynamics also impact selection, dosing, and monitoring of psychopharmacologic regimens. Optimizing management of depression and providing sound advice to older patients with depression requires knowledge and understanding of many clinical factors. The purpose of this review is to highlight salient issues in late-life depression, with a focus on the pharmacotherapy of depression.

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.

The safety and tolerability of duloxetine compared with paroxetine and placebo: a pooled analysis of 4 clinical trials

BACKGROUND

To compare the safety and tolerability of duloxetine with paroxetine and placebo in patients with major depressive disorder (MDD).

METHOD

Data from four 8-week randomized, double-blind, placebo- and paroxetine-controlled studies of duloxetine for MDD (DSM-IV criteria) were pooled to compare the safety and tolerability of duloxetine 40 to 120 mg/day with paroxetine 20 mg q.d. Two of the 4 trials included a 26-week extension.

RESULTS

The pooled database included 1466 patients (duloxetine, N = 736; paroxetine, N = 359; placebo, N = 371). No deaths occurred in the acute phase trials. Discontinuation rates for adverse events did not differ significantly for duloxetine, 8.0%, and paroxetine, 6.1%. Nausea was the most frequent treatment-emergent adverse event for duloxetine (duloxetine, 14.4%; paroxetine, 12.0%; placebo, 3.8%). Blood pressure and corrected QT (QTc) interval changes were modest and did not differ significantly for the 3 groups. Mean heart rate increased slightly in the duloxetine group, 1.0 beat/minute, and did differ significantly (p < .001) from that in the paroxetine group, but the change is of doubtful importance. Mean changes in laboratory analytes remained within the reference range. Emergent sexual dysfunction was significantly greater among duloxetine- and paroxetine-treated patients than placebo-treated patients (p = .007 vs. duloxetine and p < .001 vs. paroxetine); however, it was significantly lower in duloxetine-treated patients than in paroxetine-treated patients (46.4% vs. 61.4%; p = .015). During the extension phase, weight gain (≥ 7% of initial body weight) was greater in both active-treatment groups than in the placebo group (duloxetine, 10.8%; paroxetine, 13.8%; placebo, 3.1%), but the active-treatment groups did not differ.

CONCLUSIONS

Duloxetine is safe and well tolerated in patients with MDD, with safety and tolerability comparable to that of paroxetine.

Public and decision maker stated preferences for pharmaceutical subsidy decisions: a pilot study

BACKGROUND

Consideration of public preferences is desirable when making decisions on the subsidy of pharmaceuticals. Little is known about the preferences of the public for pharmaceutical funding decisions, and no study has directly compared the preferences of members of a pharmaceutical decision-making body with those of the public on whose behalf decisions are made.

OBJECTIVE

This article reports the findings of a pilot discrete-choice experiment (DCE) undertaken to test the concept of evaluating the consistency of public and decision maker preferences for the public subsidy of pharmaceuticals.

METHODS

A DCE was used to elicit the relative importance of gains in survival, quality of life (QOL), chance of response success and government costs in pharmaceutical funding decisions, and the impact that the initial severity of illness has on preferences. The DCE was administered to a sample of the Australian public and members of the Pharmaceutical Benefits Advisory Committee and its Economic Subcommittee. A mixed logit model was employed for analysis.

RESULTS

For both samples, increased survival, QOL and chance of response success, and a reduction in cost or uncertainty (decision makers only), increased the likelihood that a pharmaceutical would be chosen for funding. Both samples were more likely to fund a pharmaceutical that was used for the treatment of severe illness.

CONCLUSION

This study sets the foundation for future research on the relative importance of decision criteria, the contexts that impact on the criteria and the extent to which funding decisions for pharmaceuticals in Australia and elsewhere are consistent with the preferences of society.

The noradrenergic action in antidepressant treatments: pharmacological and clinical aspects

Even though noradrenaline has been recognized as one of the key neurotransmitters in the pathophysiology of major depression (MD), noradrenergic compounds have been less extensively utilized in clinical practice, compared to selective serotonin reuptake inhibitors (SSRIs). The development of the first selective noradrenergic reuptake inhibitor (NRI), Reboxetine, has not substantially changed the state of the art. In addition, Atomoxetine, a relatively pure NRI used for the treatment of ADHD, has shown mixed results when administered in augmentation to depressed subjects. Through a Medline search from 2000 to 2010, the present article provides an updated overview of the main pharmacological and clinical aspects of antidepressant classes that, partially or selectively, act on the noradrenergic systems. The noradrenergic action plays an important clinical effect in different antidepressant classes, as confirmed by the efficacy of dual action antidepressants such as the serotonin noradrenaline reuptake inhibitors (SNRIs), the noradrenergic and dopaminergic reuptake inhibitor (NDRI) Bupropion, and other compounds (e.g., Mianserin, Mirtazapine), which enhance the noradrenergic transmission. In addition, many tricyclics, such as Desipramine and Nortriptyline, have prevalent noradrenergic effect. Monoamine oxidase inhibitors (MAOIs), moreover, block the breakdown of serotonin, noradrenaline, dopamine and increase the availability of these monoamines. A novel class of antidepressants--the triple reuptake inhibitors--is under development to selectively act on serotonin, noradrenaline, and dopamine. Finally, the antidepressant effect of the atypical antipsychotic Quetiapine, indicated for the treatment of bipolar depression, is likely to be related to the noradrenergic action of its metabolite Norquetiapine. Even though a pure noradrenergic action might not be sufficient to obtain a full antidepressant effect, a pronoradrenergic action represents an important element for increasing the efficacy of mixed action antidepressants. In particular, the noradrenergic action seemed to be related to the motor activity, attention, and arousal.

Identifying HAM-A cutoffs for mild, moderate, and severe generalized anxiety disorder

The aim of the current study was to identify and evaluate cutoffs for mild, moderate, and severe ranges of Hamilton Anxiety Rating Scale (HAM-A) scores. Data were from a four-week randomized trial of treatment for generalized anxiety disorder. Measures included the HAM-A, SF-36, Hospital Anxiety and Depression Scale (HADS), and Clinical Global Impressions of Severity (CGI-S) scale. HAM-A cutoffs were identified based on literature review, expert panel input, and MANOVA models. The optimal cutoff set was evaluated based on association with clinician CGI-S ratings. The sample included 144 patients (56.3% female; 73.6% white; mean age = 35.7 years; mean baseline HAM-A score = 23.7). The optimal HAM-A score ranges were: mild anxiety = 8-14; moderate = 15-23; severe ≥ 24 (scores ≤ 7 were considered to represent no/minimal anxiety). Analysis of variance (ANOVA) models found statistically significant differences among these groups in the SF-36 and HADS. The HAM-A severity ranges closely corresponded to clinicians' CGI-S ratings. The study represents the first step towards developing severity ranges for the HAM-A. These cutoffs should be used with caution and validated in larger samples. If the proposed cutoffs are accepted for general use, they could make results more meaningful and interpretable for researchers, clinicians, and patients.

Development and validation of stability indicating method for the quantitative determination of venlafaxine hydrochloride in extended release formulation using high performance liquid chromatography

Objective:

Venlafaxine,hydrochloride is a structurally novel phenethyl bicyclic antidepressant, and is usually categorized as a serotonin–norepinephrine reuptake inhibitor (SNRI) but it has been referred to as a serotonin–norepinephrine–dopamine reuptake inhibitor. It inhibits the reuptake of dopamine. Venlafaxine HCL is widely prescribed in the form of sustained release formulations. In the current article we are reporting the development and validation of a fast and simple stability indicating, isocratic high performance liquid chromatographic (HPLC) method for the determination of venlafaxine hydrochloride in sustained release formulations.

Materials and Methods:

The quantitative determination of venlafaxine hydrochloride was performed on a Kromasil C18 analytical column (250 × 4.6 mm i.d., 5 μm particle size) with 0.01 M phosphate buffer (pH 4.5): methanol (40: 60) as a mobile phase, at a flow rate of 1.0 ml/min. For HPLC methods, UV detection was made at 225 nm.

Results:

During method validation, parameters such as precision, linearity, accuracy, stability, limit of quantification and detection and specificity were evaluated, which remained within acceptable limits.

Conclusions:

The method has been successfully applied for the quantification and dissolution profiling of Venlafaxine HCL in sustained release formulation. The method presents a simple and reliable solution for the routine quantitative analysis of Venlafaxine HCL.

Factors that impact choice of antidepressant treatment in medically complex patients

In medically complex patients with multiple comorbid illnesses who require concomitant medications, selecting the optimal antidepressant (ie, low risk of adverse effects and/or pharmacokinetic interactions) for an individual patient is critical for positive long-term patient outcomes. The serotonin-norepinephrine reuptake inhibitors (SNRls) are increasingly being used as first-line treatment for major depressive disorder (MDD) and may prove beneficial for treatment of medically complex patients.Thus, it is key for clinicians to evaluate the differences in the pharmacokinetic and tolerability profiles of the SNRI class of antidepressants, evaluating differences both within the class and compared with other antidepressants used to treat MDD.

Mirtazapine versus venlafaxine for the treatment of somatic symptoms associated with major depressive disorder: a randomized, open-labeled trial

Somatic symptoms are often important in the treatment of major depressive disorder (MDD). The aim of this open-labeled trial was to examine the efficacy of mirtazapine for the treatment of MDD with clinically significant somatic symptoms, as compared with venlafaxine. A total of 126 patients with MDD (score >/=18 on the Hamilton Rating Scale for Depression-17) were included in both the intent-to-treat (n=73 in the mirtazapine group and n=53 in the venlafaxine group) and completer analysis (n=51 and n=37, respectively). After treatment, both treatment groups showed similar improvements in depressive symptoms. Repeated measures analysis of variance for the intent-to-treat population revealed that there were no significant differences in mean change of the Symptom Check List-90-Revised (SCL-90-R) somatization subscores between the two groups. For completers, there was a significant timextreatment interaction in the SCL-90-R somatization subscores, but the differences between the two groups at endpoint did not reach statistical significance in post-hoc analysis. In conclusion, this study suggests that overall efficacies of mirtazapine and venlafaxine are similar for the treatment of overall symptoms in MDD, and both drugs may be useful for the treatment of somatic symptoms in MDD patients.

Change in formulation and its potential clinical and pharmacoeconomic value: example of extended release venlafaxine

INTRODUCTION

The 505(b)(2) route of a New Drug Application (NDA) allows published literature or previous FDA findings of safety and effectiveness to be used for approval. Such drugs are not therapeutic equivalents (i.e., generics); instead, the FDA calls them pharmaceutical alternatives. A recent example is the approval of venlafaxine extended-release (ER) tablets, developed as an alternative to the widely used ER venlafaxine capsules. The smaller size of the tablets makes them available in a 225-mg strength, which is the approved maximum dose in major depressive disorder after up-titration but currently unavailable in the capsule formulation, requiring patients on this dose to take two or three capsules; in addition, the tablets are priced at a discount compared to the capsules.

METHODS

The objective of this review was to investigate how the change in formulation of ER venlafaxine from capsules to tablets, as an example of such a change in formulation, can potentially offer value to patients and society, with a specific focus on pill burden, drug cost, and adherence. Based on a MEDLINE literature search, the pertinent literature was reviewed in a qualitative manner.

REVIEW OF THE LITERATURE

Simplifying treatment regimens, reducing pill burden, and reducing drug costs are recognized strategies for improving adherence. This can be of particular benefit in psychiatric illness because of high rates of nonadherence to treatment. Lack of adherence may negatively impact treatment outcomes and increase disease cost. As such, the ER venlafaxine tablets have the potential to reduce pill burden, improve adherence and outcomes, and reduce cost to patients and society. These preliminary findings need to be corroborated with more primary research and a systematic review of formulation changes.

CONCLUSION

A change in formulation of established therapies such as ER venlafaxine has the potential to offer clinical and pharmacoeconomic benefits to patients and society.

The effect of venlafaxine compared with other antidepressants and placebo in the treatment of major depression: a meta-analysis

OBJECTIVE

Meta-analysis of all available trials of Venlafaxine in the treatment of major depressive disorders, including treatment resistant depression and long-term relapse prevention.

METHODS

We conducted a meta-analysis comparing venlafaxine and tricyclics, or selective serotonin reuptake inhibitors (SSRIs), in major depression. We also included trials comparing venlafaxine and alternative antidepressants in subjects with treatment resistant depression, or compared with placebo in long-term relapse prevention. Trials were identified through searches of Medline, Embase, Cochrane Library and through accessing unpublished trials held by the manufacturer. Results based on intention to treat analyses where available, were pooled using theoretically exact conditional maximum likelihood methods for fixed effects (primary analyses), and numerical simulation using a Gibbs sampler for full random effects.

RESULTS

Compared to all SSRIs for the treatment of major depression (fluoxetine, paroxetine, sertraline, citalopram, escitalopram and fluvoxamine), venlafaxine was associated with a greater response [odds ratio 1.15 (95% CI 1.02-1.29)] and remission [odds ratio 1.19 (95% CI 1.06-1.34)]. Overall drop out rates appeared similar for SSRIs and venlafaxine. Compared to tricyclics, response to venlafaxine was estimated to be greater by exact method, odds ratio 1.21 (95% CI 1.03-1.43), but not statistically significantly different, using a full random effects method odds ratio 1.22 (95% CI 0.96-1.54). We observed no difference in remission rates (odds ratio 1.06 (95% CI 0.74-1.63)). Tricyclics were less well tolerated with higher overall drop out rates. Compared to alternative antidepressants in treatment resistant depression (trials included comparison with sertraline, bupropion, fluoxetine, citalopram, and one with a range of agents-mostly SSRIs), the odds ratio for response was 1.35 (95% CI 1.19-1.54). The odds ratio for remission was 1.35 (95% CI 1.20-1.52). Compared to placebo the odds ratio for relapse prevention with venlafaxine was 0.37 (95% CI 0.27-0.51).

CONCLUSION

This meta analysis provides evidence of the clinical efficacy of venlafaxine in achieving therapeutic response and remission in patients with major depression. Venlafaxine appears more effective than SSRIs, and at least as effective as tricyclic antidepressants, in the treatment of major depressive episode. Venlafaxine appeared more effective than comparators in treatment resistant depression. In addition, venlafaxine effective in reducing relapse when given long term after major depressive episode.

Change in Pain Severity With Open Label Venlafaxine Use in Patients With a Depressive Symptomatology: An Observational Study in Primary Care

Purpose.

Venlafaxine has shown benefit in the treatment of depression and pain. Worldwide data are extensively lacking investigating the outcome of chronic pain patients with depressive symptoms treated by venlafaxine in the primary care setting. This observational study aimed to elucidate the efficacy of venlafaxine and its prescription by Swiss primary care physicians and psychiatrists in patients with chronic pain and depressive symptomatology.

Subjects and methods.

We studied 505 patients with depressive symptoms suffering from chronic pain in a prospective naturalistic Swiss community based observational trial with venlafaxine in primary care. These patients have been treated with venlafaxine by 122 physicians, namely psychiatrists, general practitioners, and internists.

Results.

On average, patients were treated with 143 ± 75 mg (0–450 mg) venlafaxine daily for a follow-up of three months. Venlafaxine proved to be beneficial in the treatment of both depressive symptoms and chronic pain.

Discussion.

Although side effects were absent in most patients, physicians might have frequently omitted satisfactory response rate of depression by underdosing venlafaxine. Our results reflect the complexity in the treatment of chronic pain in patients with depressive symptoms in primary care.

Conclusion.

Further randomized dose-finding studies are needed to learn more about the appropriate dosage in treating depression and comorbid pain with venlafaxine.

An investigation of the effect of immediate and extended release venlafaxine on nocturnal melatonin and cortisol release in healthy adult volunteers

The secretion of the hormone melatonin is particularly robust to the effect of pharmacological agents. Medications may alter melatonin levels through either altering adrenergic activity or affecting liver enzymes involved in melatonin metabolism. The aim of this study was to investigate the effect of venlafaxine, a third generation antidepressant with known adrenergic properties on melatonin secretion. A further aim of the study was to investigate the correlation between plasma and salivary measures on this medication. Eight healthy adult participants (four males, four females) took part in this double blind placebo controlled randomised trial. Participants were tested on 3 nights after taking venlafaxine XR (75 mg), venlafaxine IR (75 mg) or placebo. Participants were placed in a darkened room between 1900 and 0300 h and regular temperature readings, blood and saliva samples were drawn to assess melatonin and cortisol secretion in each condition. There was no significant effect of venlafaxine IR or XR on melatonin concentrations in plasma or saliva and no effects on other circadian parameters including cortisol and temperature. It was notable that the correlation between plasma and salivary melatonin levels became poor after drug treatment. These results indicate that at low doses the mixed serotonergic and noradrenergic drug venlafaxine has no effect on nocturnal melatonin concentrations.

Venlafaxine–Propafenone Interaction Resulting in Hallucinations and Psychomotor Agitation

Objective:

To report a case of visual hallucinations and psychomotor agitation probably induced by an interaction between venlafaxine and propafenone.

Case Summary:

An 85-year-old woman was admitted for evaluation of a mood disorder on March 20, 2006. Her general practitioner had prescribed sertraline for treatment, which had started about 6 months earlier. The patient's medical history included hypertension, supraventricular tachycardia, chronic bronchitis, and arthritis, for which she received ramipril, ticlopidine, torsemide, theophylline, acetaminophen, and triazolam. The patient had also received propafenone 150 mg every 12 hours for 3 years. Results of biochemical tests were normal; however, a computed tomography (CT) scan of the brain showed signs of cortical atrophy. Sertraline was discontinued after a few days because of its reduced effectiveness and was replaced with extended-re lease venlafaxine 75 mg/day. No other changes to the patient's drug therapy were made. Four weeks later, because of the persistence of psychiatric disturbance, the venlafaxine dosage was increased to 150 mg/day. Ten days later the patient returned to our observation due to the onset of visual hallucinations lasting about 2 hours, especially at night, and psychomotor agitation. Venlafaxine was discontinued, with a complete remission of hallucinations and psychomotor agitation in about 4 days. The Naranjo probability scale indicated a probable relationship between venlafaxine and the patient's symptoms. Citalopram was started one month later for the persistence of mood disorders, with no adverse effects.

Discussion:

A CT scan documented signs of cortical atrophy in our patient's brain but excluded vascular brain injury, while clinical evaluation and anamnesis excluded a relationship between hallucinations and cortical atrophy. Genetic and pharmacologic factors may be involved in venlafaxine-induced adverse effects. Venlafaxine is metabolized primarily by CYP2D6 and is a substrate of P-glycoprotein. Propafenone, a known substrate and inhibitor of both CYP2D6 and P-glycoprotein, could therefore be involved in venlafaxine-induced hallucinations through the increase of venlafaxine plasma concentrations.

Conclusions:

To prevent the onset of clinical disturbances during venlafaxine treatment, we suggest careful evaluation of concomitant treatment with CYP2D6 or P-glycoprotein inhibitors (eg, propafenone) and, when possible, venlafaxine serum concentration monitoring.