D-VENLOR Tablets (Desvenlafaxine )

Table of Content

Major depressive disorder (MDD) is a serious disorder of enormous sociological and clinical relevance. Due to the remitting and relapsing course of MDD, its disease burden is substantial and is increasing.

Depression is believed to occur due to imbalance of monoamines, the mood-related neurotransmitters such as serotonin and norepinephrine.

The psychopathological state during depression involves various symptoms viz. low or depressed mood, anhedonia, and low energy or fatigue.

Treatment of depression essentially aims at restoring the normal balance of these neurotransmitters in the neuronal membrane, with a clinical goal of complete remission, associated with better functioning and a lower likelihood of relapse.

D-VENLOR Tablets are extended-release tablets for oral administration, which contain desvenlafaxine succinate, a structurally novel serotonin and norepinephrine reuptake inhibitor (SNRI) for the treatment of MDD. Like venlafaxine, desvenlafaxine selectively inhibits neuronal uptake of serotonin and norepinephrine and has little affinity for muscarinic, cholinergic, histamine H1 and α1 adrenergic receptors.It is not metabolized by the cytochrome P450 pathway, nor does it cause inhibition of cytochrome P450 enzymes. Due to these attributes and low protein binding compared to other antidepressants, desvenlafaxine is expected to have a low risk of drug interactions, an important potential benefit since patients with MDD have high rates of comorbid mental illness and treatment. In addition to MDD, it is effective for the treatment of associated symptoms of depression like anxiety and somatic pain.

D-VENLOR is currently available as 50 mg and 100 mg oral extended-release tablets.

Text Box:

Black Box Warning

SUICIDALITY AND ANTIDEPRESSANT DRUGS

Antidepressants increased the risk, compared to placebo, of suicidal thinking and behavior (suicidality) in children, adolescents and young adults in short-term studies of major depressive disorder (MDD) and other psychiatric disorders. Anyone considering the use of D-VENLOR Tablets or any other antidepressant in a child, adolescent or young adult must balance this risk with the clinical need. Short-term studies did not show an increase in the risk of suicidality with antidepressants, compared to placebo, in adults beyond the age of 24 years; there was a reduction in the risk with antidepressants, compared to placebo, in adults aged 65 years and older. Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. Patients of all ages who are started on antidepressant therapy should be monitored appropriately and observed closely for clinical worsening, suicidality or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with the prescriber. D-VENLOR Tablets are not approved for use in pediatric patients.

Composition

D-VENLOR 50

Each film-coated extended-release tablet contains:

Desvenlafaxine Succinate equivalent to Desvenlafaxine …….…….. 50 mg

D-VENLOR100

Each film-coated extended-release tablet contains:

Desvenlafaxine Succinate equivalent to Desvenlafaxine ………….. 100 mg

Dosage Form

Extended-release tablet

Pharmacology

Pharmacodynamics

D-VENLOR Tablets are extended-release tablets for oral administration, which contain desvenlafaxine succinate, a structurally novel serotonin and no repinephrine reuptake inhibitor (SNRI) for the treatment of MDD. Desvenlafaxine (O-desmethylvenlafaxine) is the major active metabolite of the antidepressant, venlafaxine, a medication used to treat major depressive disorder, generalized anxiety, social anxiety and panic disorders.

The clinical efficacy of desvenlafaxine succinate is thought to be related to the potentiation of these neurotransmitters in the central nervous system (CNS).  Desvenlafaxine lacks significant affinity for numerous receptors, including muscarinic-cholinergic, H1-histaminergic, or alpha1-adrenergic receptors in vitro. Desvenlafaxine also lacks monoamine oxidase (MAO) inhibitory activity.

Pharmacokinetics

The single-dose pharmacokinetics of desvenlafaxine is linear and dose-proportional in a dose range of 50 to 600 mg/day. The mean terminal half-life, t1/2, is approximately 11 hours. With once-daily dosing, steady-state plasma concentrations are achieved within approximately 4–5 days. At the steady state, multiple-dose accumulation of desvenlafaxine is linear and predictable from the single-dose pharmacokinetic profile.

Absorption

The absolute oral bioavailability of desvenlafaxine after oral administration is about 80%. A food-effect study involving the administration of desvenlafaxine to healthy subjects under fasting and fed conditions (high-fat meal) indicated that the Cmax was increased by about 16% in the fed state, while the area under the curves (AUCs)were similar. This difference was not clinically significant; therefore, desvenlafaxine can be taken without regard to meals.

Distribution

The plasma protein binding of desvenlafaxine is low (30%) and is independent of the drug concentration. The desvenlafaxine volume of distribution at the steady state following intravenous administration is 3.4 L/kg, indicating distribution into nonvascular compartments.

Metabolism

Desvenlafaxine is primarily metabolized by conjugation (mediated by UGT isoforms) and, to a minor extent, through oxidative metabolism. Cytochrome (CY) P3A4 is the CYP450 isozyme mediating the oxidative metabolism (N-demethylation) of desvenlafaxine. The CYP2D6 metabolic pathway is not involved and after administration of 100 mg, the pharmacokinetics of desvenlafaxine was similar in subjects with CYP2D6 poor and extensive metabolizer phenotypes.

Elimination

Approximately 45% of desvenlafaxine is excreted unchanged in urine at 72 hours after oral administration. Approximately 19% of the administered dose is excreted as the glucuronide metabolite and <5% as the oxidative metabolite (N, O-didesmethylvenlafaxine) in urine.

Special Populations

Age

In a study of healthy subjects administered doses of up to 300 mg, there was an approximate 32% increase in the Cmax and a 55% increase in the AUC in subjects older than 75 years of age (n = 17), compared with subjects 18 to 45 years of age (n = 16). Subjects, 65 to 75 years of age (n = 15), had no change in the Cmax, but an approximately 32% increase in the AUC, compared to subjects who were 18 to 45 years of age.

Gender

In a study of healthy subjects administered doses of up to 300 mg, women had an approximately 25% higher Cmax and an approximately 10% higher AUC than age-matched men. No adjustment of dosage on the basis of gender is needed.

Race

Pharmacokinetic analysis showed that race (White, n = 466; Black, n = 97; Hispanic,n = 39; others, n = 33) had no apparent effect on the pharmacokinetics of desvenlafaxine. No adjustment of dosage on the basis of race is needed.

Hepatic impairment

The disposition of desvenlafaxine succinate after administration of 100 mg was studied in subjects with mild (Child-Pugh A, n = 8), moderate (Child-Pugh B, n = 8), and severe (Child-Pugh C, n = 8) hepatic impairment and in healthy subjects (n = 12).Average AUC was increased by approximately 31% and 35% in patients with moderate and severe hepatic impairment, respectively, as compared to healthy subjects. Average AUC values were similar in subjects with mild hepatic impairment and healthy subjects (<5% difference).Systemic clearance (CL/F) was decreased by approximately 20% and 36% in patients with moderate and severe hepatic impairment, respectively, as compared to healthy subjects. The CL/F values were comparable in mild hepatic impairment and healthy subjects (<5% difference).The mean t1/2 changed from approximately 10 hours in healthy subjects and subjects with mild hepatic impairment to 13 and 14 hours in moderate and severe hepatic impairment, respectively. The recommended dose in patients with hepatic impairment is 50 mg/day. Dose escalation above 100 mg/day is not recommended.

Renal impairment

The disposition of desvenlafaxine after administration of 100 mg was studied in subjects with mild (n = 9), moderate (n = 8), severe (n = 7) and end-stage renal disease (; n = 9) requiring dialysis and in healthy, age-matched control subjects (n = 8). Elimination was significantly correlated with the creatinine clearance (CrCl). Increases in the AUCs of about 42% in mild renal impairment (24-hour CrCl = 50–80 mL/min), about 56% in moderate renal impairment (24-hour CrCl = 30–50 mL/min), about 108% in severe renal impairment (24-hour CrCl ≤30 mL/min), and about 116% in ESRD subjects were observed, compared with healthy, age-matched control subjects.

The mean terminal half-life (t1/2) was prolonged from 11.1 hours in the control subjects to approximately 13.5, 15.5, 17.6, and 22.8 hours in mild, moderate, severe renal impairment and ESRD subjects, respectively. Less than 5% of the drug in the body was cleared during a standard 4-hour haemodialysis procedure. The recommended dose in patients with moderate renal impairment is 50 mg per day. Dosage adjustment (50 mg every other day) is recommended in patients with severe renal impairment or ESRD. Doses should not be escalated in patients with moderate or severe renal impairment, or ESRD.

Indications

D-VENLOR Tablets are indicated for the treatment of major depressive disorder (MDD).

Dosage and Administration

Initial Treatment of MDD

The recommended dose for D-VENLOR Tablets is 50 mg once daily, with or without food.

In clinical studies, doses of 50–400 mg/day were shown to be effective, although no additional benefit was demonstrated at doses greater than 50 mg/day and adverse events and discontinuations were more frequent at higher doses.

D-VENLOR Tablets should be taken at approximately the same time each day. Tablets must be swallowed whole with fluid and not divided, crushed, chewed or dissolved.

Maintenance/Continuation/Extended Treatment

It is generally agreed that acute episodes of MDD require several months or longer of sustained pharmacologic therapy. However, the long-term efficacy of desvenlafaxine at a dose of 50 mg/day, which was effective in short-term, controlled studies, has not been further studied. Patients should be periodically reassessed to determine the need for continued treatment.

Discontinuing D-VENLOR Tablets

Symptoms associated with discontinuation of desvenlafaxine have been reported. Patients should be monitored for these symptoms when discontinuing treatment. A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, the physician may continue decreasing the dose, but at a more gradual rate.

Switching patients from other antidepressants to D-VENLOR Tablets

Discontinuation symptoms have been reported when switching patients from other antidepressants, including venlafaxine, to desvenlafaxine. Tapering of the initial antidepressant may be necessary to minimize discontinuation symptoms.

Switching patients to or from a Monoamine Oxidase Inhibitor (MAOI)

At least 14 days must elapse between discontinuation of a Monoamine oxidase inhibitor (MAOI) and initiation of therapy with D-VENLOR Tablets. In addition, at least 7 days must be allowed after stopping D-VENLOR Tablets before starting an MAOI.

Special Populations

Renal Impairment

The maximum recommended dose in patients with moderate renal impairment (24-hr creatinine clearance = 30 to 50 mL/min, Cockcroft-Gault ) is 50 mg per day. The maximum recommended dose in patients with severe renal impairment (24-hr CrCl less than 30 mL/min, C-G) or end-stage renal disease (ESRD) is 25 mg every day or 50 mg every other day. Supplemental doses should not be given to patients after dialysis.

Hepatic Impairment

The recommended dose in patients with moderate to severe hepatic impairment is 50 mg per day. Dose escalation above 100 mg per day is not recommended.

Contraindications

  • Contraindicated in case of hypersensitivity to desvenlafaxine succinate, venlafaxine hydrochloride or to any excipients in the D-VENLOR Tablets formulation.
  • D-VENLOR Tablets must not be used concomitantly in patients taking MAOIs or in patients who have taken MAOIs within the preceding 14 days due to the risk of serious, sometimes fatal, drug interactions with SNRI or SSRI treatment or with other serotonergic drugs. These interactions have been associated with symptoms that include tremor, myoclonus, diaphoresis, nausea, vomiting, flushing, dizziness, hyperthermia with features resembling neuroleptic malignant syndrome, seizures, rigidity, autonomic instability with possible rapid fluctuations of vital signs, and mental status changes that include extreme agitation progressing to delirium and coma. Based on the half-life of desvenlafaxine, at least 7 days should be allowed after stopping D-VENLOR Tablets before starting a MAOI.

Warnings and Precautions

Suicidal Thoughts and Behaviors in Children, Adolescents and Young Adults

Patients with MDD, both adult and paediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behaviour (suicidality) or unusual changes in behaviour, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders, and these disorders themselves are the strongest predictors of suicide. There has been a long-standing concern, however, that antidepressants may have a role in inducing the worsening of depression and the emergence of suicidality in certain patients during the early phases of treatment. Pooled analyses of short-term, placebo-controlled studies of antidepressant drugs (SSRIs and others) showed that these drugs increase the risk of suicidal thinking and behaviour (suicidality) in children, adolescents, and young adults (ages: 18 to 24 years) with MDD and other psychiatric disorders. Short-term studies did not show an increase in the risk of suicidality with antidepressants, compared to placebo, in adults beyond the age of 24 years; there was a reduction with antidepressants compared to placebo in adults aged 65 years and older.

It is unknown whether the suicidality risk extends to longer-term use, i.e., beyond several months. However, there is substantial evidence from placebo-controlled maintenance studies in adults with depression that the use of antidepressants can delay the recurrence of depression.

All patients being treated with antidepressants for any indication should be monitored appropriately and observed closely for clinical worsening, suicidality, and unusual changes in behaviour, especially during the initial few months of a course of drug therapy or at times of dose changes, either increases or decreases.

The following symptoms — anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania and mania — have been reported in adult and paediatric patients being treated with antidepressants for MDD as well as for other indications, both psychiatric and non-psychiatric. Although a causal link between the emergence of such symptoms and either the worsening of depression and/or the emergence of suicidal impulses has not been established, there is concern that such symptoms may represent precursors to emerging suicidality.

Consideration should be given to changing the therapeutic regimen, including possibly discontinuing the medication, in patients whose depression is persistently worse or who are experiencing emergent suicidality or symptoms that might be precursors to worsening depression or suicidality, especially if these symptoms are severe, abrupt in onset or were not part of the patient’s presenting symptoms.

If the decision has been made to discontinue treatment, medication should be tapered, as rapidly as is feasible, but with recognition that abrupt discontinuation can be associated with certain symptoms.

Families and caregivers of patients being treated with antidepressants for MDD or other indications, both psychiatric and non-psychiatric, should be alerted about the need to monitor patients for the emergence of agitation, irritability, unusual changes in behaviour and the other symptoms described above, as well as the emergence of suicidality, and to report such symptoms immediately to healthcare providers. Such monitoring should include daily observation by families and caregivers. Prescriptions for desvenlafaxine should be written for the smallest quantity of tablets consistent with good patient management, in order to reduce the risk of overdose.

Screening Patients for Bipolar Disorder

A major depressive episode may be the initial presentation of bipolar disorder. It is generally believed (though not established in controlled studies) that treating such an episode with an antidepressant alone may increase the likelihood of precipitation of a mixed/manic episode in patients at risk for bipolar disorder. Whether any of the symptoms described above represent such a conversion is unknown. However, prior to initiating treatment with an antidepressant, patients with depressive symptoms should be adequately screened to determine if they are at risk for bipolar disorder; such screening should include a detailed psychiatric history, including a family history of suicide, bipolar disorder and depression. It should be noted that desvenlafaxine is not approved for use in treating bipolar depression.

Serotonin Syndrome

The development of a potentially life-threatening serotonin syndrome or neuroleptic malignant syndrome-like reactions have been reported with SNRIs and SSRIs alone, including desvenlafaxine treatment, but particularly with concomitant use of serotonergic drugs (including triptans) with drugs that impair the metabolism of serotonin (including MAOIs) or with antipsychotics or other dopamine antagonists. Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, and hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination) and/or gastrointestinal symptoms (e.g., nausea, vomiting, and diarrhoea). Serotonin syndrome, in its most severe form can resemble neuroleptic malignant syndrome, which includes hyperthermia, muscle rigidity, autonomic instability with possible rapid fluctuation of vital signs and mental status changes. Patients should be monitored for the emergence of serotonin syndrome or neuroleptic malignant syndrome-like signs and symptoms.

The concomitant use of desvenlafaxine with MAOIs intended to treat depression is contraindicated. If concomitant treatment of desvenlafaxine with a 5-hydroxytryptamine receptor agonist (triptan) is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases. The concomitant use of desvenlafaxine with serotonin precursors (such as tryptophan) is not recommended.

Treatment with desvenlafaxine and any concomitant serotonergic or anti-dopaminergic agents, including antipsychotics, should be discontinued immediately if the above events occur and supportive symptomatic treatment should be initiated.

Elevated Blood Pressure

Patients receiving desvenlafaxine should have regular monitoring of blood pressure since increases in blood pressure were observed in clinical studies. Pre-existing hypertension should be controlled before initiating treatment with desvenlafaxine. Caution should be exercised in treating patients with pre-existing hypertension or other underlying conditions that might be compromised by increases in the blood pressure. Cases of elevated blood pressure requiring immediate treatment have been reported with desvenlafaxine.

Sustained blood pressure increases could have adverse consequences. For patients who experience a sustained increase in blood pressure while receiving desvenlafaxine, either dose reduction or discontinuation should be considered.

Treatment with desvenlafaxine at all doses from 50 mg/day to 400 mg/day in controlled studies was associated with sustained hypertension, defined as treatment-emergent supine diastolic blood pressure) ≥90 mm Hg and ≥10 mm Hg above baseline for three consecutive on-therapy visits . Analyses of patients in controlled studies on desvenlafaxine, who met the criteria for sustained hypertension, revealed a consistent increase in the proportion of patients who developed sustained hypertension. This was seen at all doses, with a suggestion of a higher rate at 400 mg/day.

Table 1: Proportion of patients with sustained elevation of supine diastolic blood pressure

Treatment Group

Proportion of Patients with Sustained Hypertension

Placebo

0.5%

Desvenlafaxine 50 mg/day

1.3%

Desvenlafaxine 100 mg/day

0.7%

Desvenlafaxine 200 mg/day

1.1%

Desvenlafaxine 400 mg/day

2.3%

Abnormal Bleeding

SSRIs and SNRIs, including desvenlafaxine, may increase the risk of bleeding events. Concomitant use of aspirin, NSAIDs, warfarin and other anticoagulants may add to this risk. Case reports and epidemiological studies (case-control and cohort design) have demonstrated an association between the use of drugs that interfere with serotonin reuptake and the occurrence of gastrointestinal bleeding. Bleeding events related to SSRIs and SNRIs have ranged from ecchymosis, haematoma, epistaxis and petechiae to life-threatening haemorrhages. Patients should be cautioned about the risk of bleeding associated with the concomitant use of desvenlafaxine and NSAIDs, aspirin or other drugs that affect coagulation or bleeding.

Angle-Closure Glaucoma

The pupillary dilation that occurs following use of many antidepressant drugs including D-Venlor may trigger an angle closure attack in a patient with anatomically narrow angles who does not have a patent iridectomy.

Activation of Mania/Hypomania

During all MDD and vasomotor symptoms(VMS) Phase 2 and Phase 3 studies, mania was reported for approximately 0.1% of patients treated with desvenlafaxine. Activation of mania/hypomania has also been reported in a small proportion of patients with major affective disorder who were treated with other marketed antidepressants. As with all antidepressants, desvenlafaxine should be used cautiously in patients with a history or family history of mania or hypomania.

Discontinuation of Treatment with desvenlafaxine

Discontinuation symptoms have been systematically and prospectively evaluated in patients treated with desvenlafaxine during clinical studies in MDD. Abrupt discontinuation or dose reduction has been associated with the appearance of new symptoms that include dizziness, nausea, headache, irritability, insomnia, diarrhoea, anxiety, fatigue, abnormal dreams and hyperhidrosis. In general, discontinuation events occurred more frequently with longer duration of therapy.

During marketing of SNRIs and SSRIs, there have been spontaneous reports of adverse events occurring upon discontinuation of these drugs, particularly when abrupt, including the following: dysphoric mood, irritability, agitation, dizziness, sensory disturbances (e.g., paraesthesia, such as electric shock sensations), anxiety, confusion, headache, lethargy, emotional lability, insomnia, hypomania, tinnitus and seizures. While these events are generally self-limiting, there have been reports of serious discontinuation symptoms.

Patients should be monitored for these symptoms when discontinuing treatment with desvenlafaxine. A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, the physician may continue decreasing the dose, but at a more gradual rate.

Seizure

Cases of seizure have been reported in pre-marketing clinical studies with desvenlafaxine. Desvenlafaxine has not been systematically evaluated in patients with a seizure disorder. Patients with a history of seizures were excluded from pre-marketing clinical studies. Desvenlafaxine should be prescribed with caution in patients with a seizure disorder.

Hyponatremia

Hyponatremia may occur as a result of treatment with SSRIs and SNRIs, including desvenlafaxine. In many cases, this hyponatremia appears to be the result of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Cases with serum sodium lower than 110 mmol/L have been reported. Elderly patients may be at greater risk of developing hyponatremia with SSRIs and SNRIs. Also, patients taking diuretics or who are otherwise volume depleted can be at greater risk. Discontinuation of desvenlafaxine should be considered in patients with symptomatic hyponatraemia and appropriate medical intervention should be instituted. Signs and symptoms of hyponatremia include headache, difficulty concentrating, memory impairment, confusion, weakness, and unsteadiness, which can lead to falls. Signs and symptoms associated with more severe and/or acute cases have included hallucination, syncope, seizure, coma, respiratory arrest, and death.

Interstitial Lung Disease and Eosinophilic Pneumonia

Interstitial lung disease and eosinophilic pneumonia associated with venlafaxine (the parent drug of desvenlafaxine) therapy have been rarely reported. The possibility of these adverse events should be considered in patients treated with desvenlafaxine who present with progressive dyspnea, cough, or chest discomfort. Such patients should undergo a prompt medical evaluation, and discontinuation of desvenlafaxine should be considered.

Drug Interactions

MAOIs

Adverse reactions, some of which were serious, have been reported in patients who have recently been discontinued from a MAOI and started on antidepressants with pharmacological properties similar to desvenlafaxine (SNRIs or SSRIs) or who have recently had SNRI or SSRI therapy discontinued prior to initiation of a MAOI. Do not use MAOIs intended to treat psychiatric disorders with desvenlafaxine or within 7 days of stopping treatment with desvenlafaxine. Do not use desvenlafaxine within 14 days of stopping an MAOI intended to treat psychiatric disorders. In addition, do not start desvenlafaxine in a patient who is being treated with linezolid or intravenous methylene blue.

Serotonergic Drugs

Based on the mechanism of action of desvenlafaxine and the potential for serotonin syndrome, caution is advised when desvenlafaxine is co-administered with other drugs that may affect the serotonergic neurotransmitter systems.

Drugs that Interfere with Haemostasis (e.g., NSAIDs, Aspirin and Warfarin)

Serotonin release by platelets plays an important role in haemostasis. Epidemiological studies of case-control and cohort design have demonstrated an association between the use of psychotropic drugs that interfere with serotonin reuptake and the occurrence of upper gastrointestinal bleeding. These studies have also shown that concurrent use of a non-steroidal anti-inflammatory drug(NSAID) or aspirin may potentiate this risk of bleeding. Altered anticoagulant effects, including increased bleeding, have been reported when SSRIs and SNRIs are co-administered with warfarin. Patients receiving warfarin therapy should be carefully monitored when desvenlafaxine is initiated or discontinued.

Ethanol

A clinical study has shown that desvenlafaxine does not increase the impairment of mental and motor skills caused by ethanol. However, as with all CNS-active drugs, patients should be advised to avoid alcohol consumption while taking desvenlafaxine.

Potential for Other Drugs to Affect Desvenlafaxine

Inhibitors of CYP3A4 (ketoconazole)

CYP3A4 is a minor pathway for the metabolism of desvenlafaxine. In a clinical study, ketoconazole (200 mg b.i.d.) increased the area under the concentration versus time curve (AUC) of desvenlafaxine (400 mg single dose) by about 43% and the Cmax by about 8%. Concomitant use of desvenlafaxine with potent inhibitors of CYP3A4 may result in higher concentrations of desvenlafaxine.

Inhibitors of other CYP enzymes

Based on in vitro data, drugs that inhibit CYP isozymes 1A1, 1A2, 2A6, 2D6, 2C8, 2C9, 2C19 and 2E1 are not expected to have significant impact on the pharmacokinetic profile of desvenlafaxine.

Potential for Desvenlafaxine to Affect Other Drugs

Drugs metabolized by CYP2D6 (desipramine)

In vitro studies showed a minimal inhibitory effect of desvenlafaxine on CYP2D6.Clinical studies have shown that desvenlafaxine does not have a clinically relevant effect on CYP2D6 metabolism at the dose of 100 mg daily. When desvenlafaxine succinate was administered at a dose of 100 mg daily in conjunction with a single 50 mg dose of desipramine, a CYP2D6 substrate, the Cmax and AUC of desipramine increased by approximately 25% and 17%, respectively. When 400 mg (8 times the recommended 50 mg dose) was administered, the Cmax and AUC of desipramine increased approximately by 50% and 90%, respectively. Concomitant use of desvenlafaxine with a drug metabolized by CYP2D6 can result in higher concentrations of that drug.

Drugs metabolized by CYP3A4 (midazolam)

In vitro, desvenlafaxine does not inhibit or induce the CYP3A4 isozyme.

In a clinical study, desvenlafaxine 400 mg daily (8 times the recommended 50 mg dose) was co-administered with a single 4 mg dose of midazolam (a CYP3A4 substrate). The AUC and Cmax of midazolam decreased by approximately 31% and 16%, respectively. Concomitant use of desvenlafaxine with a drug metabolized by CYP3A4 can result in lower exposures to that drug.

Drugs metabolized by CYP1A2, 2A6, 2C8, 2C9 and 2C19

In vitro, desvenlafaxine does not inhibit CYP1A2, 2A6, 2C8, 2C9, and 2C19 isozymes and would not be expected to affect the pharmacokinetics of drugs that are metabolized by these CYP isozymes.

P-glycoprotein Transporter

In vitro, desvenlafaxine is not a substrate or an inhibitor for the P-glycoprotein transporter. The pharmacokinetics of desvenlafaxine isunlikely to be affected by drugs that inhibit the P-glycoprotein transporter, and desvenlafaxine is not likely to affect the pharmacokinetics of drugs that are substrates of the P-glycoprotein transporter.

Co-administration of Drugs Containing Desvenlafaxine and Venlafaxine

Desvenlafaxine is the major active metabolite of venlafaxine. Products containing desvenlafaxine and products containing venlafaxine should not be used concomitantly with desvenlafaxine.

Renal Impairment

In subjects with renal impairment, the clearance of desvenlafaxine was decreased. In subjects with severe renal impairment (24-hour CrCl <30 mL/min) and ESRD, the elimination half-lives were significantly prolonged, increasing exposures to desvenlafaxine; therefore, dosage adjustment is recommended in these patients.

Hepatic Impairment

The mean t1/2 changed from approximately 10 hours in healthy subjects and subjects with mild hepatic impairment to 13 and 14 hours in moderate and severe hepatic impairment, respectively. The recommended dose in patients with hepatic impairment is 50 mg/day. Dose escalation above 100 mg/day is not recommended.

Pregnancy

Patients should be advised to notify their physician if they become pregnant or intend to become pregnant during therapy.

Teratogenic Effects — Pregnancy Category C

There are no adequate and well-controlled studies of desvenlafaxine in pregnant women. Therefore, desvenlafaxine should be used during pregnancy only if the potential benefits justify the potential risks.

Non-Teratogenic Effects

Neonates exposed to SNRIs or SSRIs late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support and tube feeding. Such complications can arise immediately upon delivery. Reported clinical findings have included respiratory distress, cyanosis, apnoea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycaemia, hypotonia, hypertonia, hyperreflexia, tremor, jitteriness, irritability and constant crying. These features are consistent with either a direct toxic effect of SSRIs and SNRIs or, possibly, a drug discontinuation syndrome. It should be noted that, in some cases, the clinical picture is consistent with serotonin syndrome. When treating a pregnant woman with desvenlafaxine during the third trimester, the physician should carefully consider the potential risks and benefits of treatment.

Labour and Delivery

The effect of desvenlafaxine on labour and delivery in humans is unknown. Desvenlafaxine should be used during labour and delivery only if the potential benefits justify the potential risks.

Lactation

Desvenlafaxine (O-desmethylvenlafaxine) is excreted in human milk. Because of the potential for serious adverse reactions in nursing infants from desvenlafaxine, a decision should be made whether or not to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. Only administer desvenlafaxine to nursing mothers if the expected benefits outweigh any possible risk.

Paediatric Use

Safety and effectiveness in the paediatric population have not been established. Anyone considering the use of desvenlafaxine in a child or adolescent must balance the potential risks with the clinical need.

Geriatric Use

For elderly patients, possible reduced renal clearance of desvenlafaxine should be considered when determining dose. If desvenlafaxine is poorly tolerated, dosing on every other day can be considered.

SSRIs and SNRIs, including desvenlafaxine, have been associated with cases of clinically significant hyponatremia in elderly patients, who may be at greater risk for this adverse event. Greater sensitivity of some older individuals cannot be ruled out.

Drug abuse and dependence

Controlled Substance

Desvenlafaxine is not a controlled substance.

Undesirable Effects

The most commonly observed adverse reactions in desvenlafaxine-treated MDD patients in short-term, fixed-dose studies (incidence ≥5% and at least twice the rate of placebo in the 50 or 100 mg dose groups) were nausea, dizziness, insomnia, hyperhidrosis, constipation, somnolence, decreased appetite, anxiety, and specific male sexual function disorders.

Combined across 8-week placebo-controlled, pre-marketing studies for MDD, 12% of the 1,834 patients who received desvenlafaxine (range: 50 to 400 mg) discontinued treatment due to an adverse event, compared with 3% of the 1,116 placebo-treated patients in those studies. At the recommended dose of 50 mg, the discontinuation rate due to an adverse event for desvenlafaxine (4.1%) was similar to the rate for placebo (3.8%). For the 100 mg dose of desvenlafaxine tablets, the discontinuation rate due to an adverse event was 8.7%.

Adverse events reported in association with abrupt discontinuation, dose reduction or tapering of treatment in MDD clinical studies at a rate of ≥5% included dizziness, nausea, headache, irritability, insomnia, diarrhoea, anxiety, abnormal dreams, fatigue and hyperhidrosis. In general, discontinuation events occurred more frequently with longer duration of therapy.

Table 2 shows the incidence of common adverse reactions that occurred in ≥2% of desvenlafaxine-treated MDD patients at any dose in the 8-week, placebo-controlled, fixed-dose, pre-marketing clinical studies. In general, the adverse reactions were most frequent in the first week of treatment.

Table 2: Common adverse reactions: Percentage of patients (≥2% in any fixed-dose group) in MDD 8-week placebo-controlled studiesa

 

Percentage of Patients Reporting Reaction

System Organ Class

Preferred term

Desvenlafaxine

Placebo

50 mg

100 mg

200 mg

400 mg

Cardiac disorders

Palpitations

2

1

3

2

3

Tachycardia

1

1

<1

1

2

Blood pressure increased

1

1

1

2

2

Gastrointestinal disorders

Nausea

10

22

26

36

41

Dry mouth

9

11

17

21

25

Diarrhoea

9

11

9

7

5

Constipation

4

9

9

10

14

Vomiting

3

3

4

6

9

General disorders and administration site conditions

Fatigue

4

7

7

10

11

Chills

1

1

<1

3

4

Feeling jittery

1

1

2

3

3

Asthenia

1

1

2

1

1

Metabolism and nutrition disorders

Decreased appetite

2

5

8

10

10

Weight decreased

1

2

1

1

2

Nervous system disorders

Dizziness

5

13

10

15

16

Somnolence

4

4

9

12

12

Headache

23

20

22

29

25

Tremor

2

2

3

9

9

Paraesthesia

1

2

2

1

3

Disturbance in attention

<1

<1

1

2

1

Psychiatric disorders

Insomnia

6

9

12

14

15

Anxiety

2

3

5

4

4

Nervousness

1

<1

1

2

2

Irritability

1

2

2

2

2

Abnormal dreams

1

2

3

2

4

Renal and urinary disorders

Urinary hesitation

0

<1

1

2

2

Respiratory, thoracic and mediastinal disorders

Yawning

<1

1

1

4

3

Skin and subcutaneous tissue disorders

Hyperhidrosis

4

10

11

18

21

Rash

<1

1

1

2

<1

Special Senses

Vision blurred

1

3

4

4

4

Mydriasis

<1

2

2

6

6

Vertigo

1

2

1

5

3

Tinnitus

1

2

1

1

2

Dysgeusia

1

1

1

1

2

Vascular disorders

Hot flush

<1

1

1

2

2

                 

a Percentage based on the number of patients (placebo, n = 636; desvenlafaxine 50 mg, n = 317; desvenlafaxine 100 mg, n = 424; desvenlafaxine 200 mg, n = 307; desvenlafaxine 400 mg, n = 317).

Sexual function adverse reactions that occurred in ≥2% of desvenlafaxine treated MDD patients in any fixed-dose group (8-week, placebo-controlled, fixed-dose and flexible-dose, pre-marketing clinical studies) were: anorgasmia, decreased libido, abnormal orgasm, delayed ejaculation, erectile dysfunction, ejaculation disorder, ejaculation failure, sexual dysfunction in males and anorgasmia in females.

Other infrequent adverse reactions, occurring at an incidence of <2% in MDD patients treated with desvenlafaxine were: hypersensitivity, increased weight, abnormal liver function test, increased blood prolactin, convulsion, syncope, extra pyramidal disorder, musculoskeletal stiffness, depersonalization, hypomania, epistaxis, orthostatic hypotension.

In clinical studies, there were uncommon reports of ischaemic cardiac adverse events, including myocardial ischemia, myocardial infarction and coronary occlusion requiring revascularization; these patients had multiple underlying cardiac risk factors. More patients experienced these events during desvenlafaxine treatment as compared to placebo.

Laboratory, ECG and vital sign changes observed in MDD clinical studies

The following changes were observed in placebo-controlled, short-term, pre-marketing MDD studies with desvenlafaxine:

Lipids   

Elevations in fasting serum total cholesterol, LDL cholesterol and triglycerides occurred in the controlled studies. Some of these abnormalities were considered potentially clinically significant.

Proteinuria

Proteinuria, greater than or equal to trace, was observed in the fixed-dose controlled studies. This proteinuria was not associated with increases in BUN or creatinine and was generally transient.

ECG changes

ECGs (electrocardiograms) were obtained from 1,492 desvenlafaxine-treated patients with MDD and 984 placebo-treated patients in clinical studies lasting up to 8 weeks. No clinically relevant differences were observed between desvenlafaxine-treated patients and placebo-treated patients for QT, QTc, PR and QRS intervals. In a thorough QTc study with prospectively determined criteria, desvenlafaxine did not cause QT prolongation. No difference was observed between placebo and desvenlafaxine treatments for the QRS interval.

Vital sign changes

Table 3 summarizes the changes that were observed in placebo-controlled, short-term, pre-marketing studies with desvenlafaxine in patients with MDD (doses of 50 to 400 mg).

Table 3: Mean changes in vital signs at final on therapy for all short-term, fixed-dose controlled studies

 

Desvenlafaxine Tablets

 

Placebo

50 mg

100 mg

200 mg

400 mg

Blood pressure

Supine systolic bloodpressure (mm Hg)

–1.4

1.2

2.0

2.5

2.1

Supine diastolic blood pressure

(mm Hg)

–0.6

0.7

0.8

1.8

2.3

Pulse rate

Supine pulse rate (bpm)

–0.3

1.3

1.3

0.9

4.1

Weight (kg)

0.0

-0.4

–0.6

-0.9

–1.1

At the final on-therapy assessment in the 6-month, double-blind, placebo-controlled phase of a long-term study in patients who had responded to desvenlafaxine during the initial 12-week, open-label phase, there was no statistical difference in the mean weight change between desvenlafaxine and placebo-treated patients.

Orthostatic hypotension

In the short-term, placebo-controlled clinical studies with doses of 50–400 mg, systolic orthostatic hypotension (decrease ≥30 mm Hg from supine to standing position) occurred more frequently in patients ≥65 years of age receiving desvenlafaxine (8.0%, 7/87) versus placebo (2.5%, 1/40), compared to patients <65 years of age receiving desvenlafaxine (0.9%, 18/1,937) versus placebo (0.7%, 8/1,218).

Overdosage

There is limited clinical experience with desvenlafaxine succinate over dosage in humans. In pre-marketing clinical studies, no cases of fatal acute overdose of desvenlafaxine were reported.

Among the patients included in the MDD pre-marketing studies of desvenlafaxine, there were four adults who ingested desvenlafaxine succinate (4000 mg , 900, 1800 and 5200 mg ); all patients recovered. In addition, one patient’s 11-month-old child accidentally ingested 600 mg of desvenlafaxine succinate, was treated, and recovered. The adverse reactions reported within 5 days of an overdose >600 mg that were possibly related to desvenlafaxine included headache, vomiting, agitation, dizziness, nausea, constipation, diarrhoea, dry mouth, paraesthesia and tachycardia.

Desvenlafaxine is a major active metabolite of venlafaxine. Overdose experience reported with venlafaxine (parent drug of desvenlafaxine) is presented below.

In post marketing experience, overdose with venlafaxine has occurred predominantly in combination with alcohol and/or other drugs. The most commonly reported events in over dosage include tachycardia, changes in level of consciousness (ranging from somnolence to coma), mydriasis, seizures, and vomiting. ECG changes (e.g., prolongation of QT interval, bundle branch block, QRS prolongation), sinus and ventricular tachycardia, bradycardia, hypotension, rhabdomyolysis, vertigo, liver necrosis, serotonin syndrome, and death have been reported.

Published retrospective studies report that venlafaxine over dosage may be associated with an increased risk of fatal outcomes compared to that observed with SSRI antidepressant products, but lower than that for tricyclic antidepressants. Epidemiological studies have shown that venlafaxine-treated patients have a higher pre-existing burden of suicide risk factors than SSRI-treated patients. The extent to which the finding of an increased risk of fatal outcomes can be attributed to the toxicity of venlafaxine in over dosage, as opposed to some characteristic(s) of venlafaxine-treated patients, is not clear.

Prescriptions for desvenlafaxine should be written for the smallest quantity of tablets consistent with good patient management, in order to reduce the risk of overdose.

Treatment should consist of those general measures employed in the management of over dosage with any SSRI/SNRI. Ensure an adequate airway, oxygenation and ventilation. Monitor cardiac rhythm and vital signs. General supportive and symptomatic measures are also recommended. Gastric lavage with a large-bore orogastric tube with appropriate airway protection, if needed, may be indicated if performed soon after ingestion or in symptomatic patients. Activated charcoal should be administered. Induction of emesis is not recommended. Because of the moderate volume of distribution of this drug, forced diuresis, dialysis, haemoperfusion and exchange transfusion are unlikely to be of benefit. No specific antidotes for desvenlafaxine are known.

In managing an overdose, consider the possibility of multiple-drug involvement. The physician should consider contacting a poison control centre for additional information on the treatment of any overdose.

Shelf-Life

2 years

Storage and Handling Instructions

Store in a dry and dark place at a temperature below 25°C.

Packaging Information

D-VENLOR 50…………………Strip of 10 tablets

D-VENLOR 100……………….Strip of 10 tablets

Last Updated: Jul 2015
Last Reviewed: Jul 2015