Venlafaxine

INDICATIONS AND USAGE Major Depressive Disorder Venlafaxine Hydrochloride Extended-Release Capsules USP are indicated for the treatment of major depressive disorder. The efficacy of Venlafaxine Hydrochloride Extended-Release Capsules USP in the treatment of major depressive disorder was established in 8 and 12 week controlled trials of adult outpatients whose diagnoses corresponded most closely to the DSM-III-R or DSM-IV category of major depressive disorder (see Clinical Trials ). A major depressive episode (DSM-IV) implies a prominent and relatively persistent (nearly every day for at least 2 weeks) depressed mood or the loss of interest or pleasure in nearly all activities, representing a change from previous functioning, and includes the presence of at least five of the following nine symptoms during the same two-week period: depressed mood, markedly diminished interest or pleasure in usual activities, significant change in weight and/or appetite, insomnia or hypersomnia, psychomotor agitation or retardation, increased fatigue, feelings of guilt or worthlessness, slowed thinking or impaired concentration, a suicide attempt or suicidal ideation. The efficacy of Venlafaxine Hydrochloride Tablets USP (immediate release) in the treatment of major depressive disorder in adult inpatients meeting diagnostic criteria for major depressive disorder with melancholia was established in a 4 week controlled trial (see Clinical Trials ). The safety and efficacy of Venlafaxine Hydrochloride Extended-Release Capsules USP in hospitalized depressed patients have not been adequately studied. The efficacy of Venlafaxine Hydrochloride Extended-Release Capsules USP in maintaining a response in major depressive disorder for up to 26 weeks following 8 weeks of acute treatment was demonstrated in a placebo-controlled trial. The efficacy of Venlafaxine Hydrochloride Tablets USP (immediate release) in maintaining a response in patients with recurrent major depressive disorder who had responded and continued to be improved during an initial 26 weeks of treatment and were then followed for a period of up to 52 weeks was demonstrated in a second placebo-controlled trial (see Clinical Trials ). Nevertheless, the physician who elects to use Venlafaxine Hydrochloride Tablets USP/Venlafaxine Hydrochloride Extended-Release Capsules USP for extended periods should periodically re-evaluate the long-term usefulness of the drug for the individual patient (see DOSAGE AND ADMINISTRATION ). Panic Disorder Venlafaxine Hydrochloride Extended-Release Capsules USP are indicated for the treatment of panic disorder, with or without agoraphobia, as defined in DSM-IV. Panic disorder is characterized by the occurrence of unexpected panic attacks and associated concern about having additional attacks, worry about the implications or consequences of the attacks, and/or a significant change in behavior related to the attacks. Panic disorder (DSM-IV) is characterized by recurrent, unexpected panic attacks, i.e., a discrete period of intense fear or discomfort, in which four (or more) of the following symptoms develop abruptly and reach a peak within 10 minutes: 1) palpitations, pounding heart, or accelerated heart rate; 2) sweating; 3) trembling or shaking; 4) sensations of shortness of breath or smothering; 5) feeling of choking; 6) chest pain or discomfort; 7) nausea or abdominal distress; 8) feeling dizzy, unsteady, lightheaded, or faint; 9) derealization (feelings of unreality) or depersonalization (being detached from oneself); 10) fear of losing control; 11) fear of dying; 12) paresthesias (numbness or tingling sensations); 13) chills or hot flushes. The efficacy of Venlafaxine Hydrochloride Extended-Release Capsules USP in the treatment of panic disorder was established in two 12 week placebo-controlled trials in adult outpatients with panic disorder (DSM-IV). The efficacy of Venlafaxine Hydrochloride Extended-Release Capsules USP in prolonging time to relapse in panic disorder among responders following 12 weeks of open-label acute treatment was demonstrated in a placebo-controlled study (see CLINICAL PHARMACOLOGY, Clinical Trials ). Nevertheless, the physician who elects to use Venlafaxine Hydrochloride Extended-Release Capsules USP for extended periods should periodically re-evaluate the long-term usefulness of the drug for the individual patient (see DOSAGE AND ADMINISTRATION ).

DOSAGE AND ADMINISTRATION Venlafaxine extended-release tablets should be administered in a single dose with food either in the morning or in the evening at approximately the same time each day. Each tablet should be swallowed whole with fluid and not divided, crushed, chewed, or placed in water. Initial Treatment ( 2.1 ) Indication Starting Dose Dose Increase Maximum Dose Major Depressive Disorder 75 mg/day (in some patients, 37.5 mg/day for 4-7 days) 75 mg/day increments at intervals of 4 days or longer 225 mg/day Social Anxiety Disorder 75 mg/day No benefit at higher doses 75 mg/day Venlafaxine extended-release tablets should be taken as a single daily dose with food in either the morning or evening at the same time each day. ( 2 ) Discontinuation: Gradual; individualized as necessary. ( 2.4 ) 2.1 Initial Treatment Major Depressive Disorder For most patients, the recommended starting dose for venlafaxine extended-release tablets is 75 mg/day, administered in a single dose. In the clinical trials establishing the efficacy of venlafaxine hydrochloride extended-release capsules in moderately depressed outpatients, the initial dose of venlafaxine was 75 mg/day. For some patients, it may be desirable to start at 37.5 mg/day for 4 to 7 days to allow new patients to adjust to the medication before increasing to 75 mg/day. While the relationship between dose and antidepressant response for venlafaxine hydrochloride extended-release capsules has not been adequately explored, patients not responding to the initial 75 mg/day dose may benefit from dose increases to a maximum of approximately 225 mg/day. Dose increases should be in increments of up to 75 mg/day, as needed, and should be made at intervals of not less than 4 days, since steady state plasma levels of venlafaxine and its major metabolites are achieved in most patients by day 4. In the clinical trials establishing efficacy, upward titration was permitted at intervals of 2 weeks or more; the average doses were about 140 to 180 mg/day [ see Clinical Studies ( 14 ) ]. It should be noted that, while the maximum recommended dose for moderately depressed outpatients is also 225 mg/day for venlafaxine hydrochloride immediate-release tablets, more severely depressed inpatients in one study of the development program for that product responded to a mean dose of 350 mg/day (range of 150 to 375 mg/day). Whether or not higher doses of venlafaxine extended-release tablets are needed for more severely depressed patients is unknown; however, the experience with venlafaxine hydrochloride extended-release capsule doses higher than 225 mg/day is very limited . Social Anxiety Disorder (Social Phobia) The recommended dose is 75 mg/day, administered in a single dose. There was no evidence that higher doses confer any additional benefit . 2.2 Maintenance Treatment There is no body of evidence available from controlled trials to indicate how long patients with major depressive disorder should be treated with venlafaxine extended-release tablets. It is generally agreed that acute episodes of major depressive disorder require several months or longer of sustained pharmacological therapy beyond response to the acute episode. In one study, in which patients responding during 8 weeks of acute treatment with venlafaxine hydrochloride extended-release capsules were assigned randomly to placebo or to the same dose of venlafaxine hydrochloride extended-release capsules (75, 150, or 225 mg per day, qAM) during 26 weeks of maintenance treatment as they had received during the acute stabilization phase, longer-term efficacy was demonstrated. A second longer-term study has demonstrated the efficacy of venlafaxine hydrochloride immediate-release tablets in maintaining a response in patients with recurrent major depressive disorder who had responded and continued to be improved during an initial 26 weeks of treatment and were then randomly assigned to placebo or venlafaxine hydrochloride immediate-release tablets for periods of up to 52 weeks on the same dose (100 to 200 mg/day, on a b.i.d. schedule)[ see Clinical Studies ( 14 ) ]. Based on these limited data, it is not known whether or not the dose of venlafaxine extended-release tablets needed for maintenance treatment is identical to the dose needed to achieve an initial response. Patients should be periodically reassessed to determine the need for maintenance treatment and the appropriate dose for such treatment. 2.3 Special Populations Treatment of Pregnant Women During the Third Trimester Neonates exposed to venlafaxine hydrochloride extended-release capsules, other SNRIs, or SSRIs, late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding [ see Use in Specific Populations ( 8.1 ) ]. When treating pregnant women with venlafaxine extended-release tablets during the third trimester, the physician should carefully consider the potential risks and benefits of treatment. Patients with Hepatic Impairment Given the decrease in clearance and increase in elimination half-life for both venlafaxine and ODV that is observed in patients with hepatic cirrhosis and mild and moderate hepatic impairment compared with normal subjects [ see Use in Specific Populations ( 8.6 ) and Clinical Pharmacology ( 12.3 ) ], it is recommended that the total daily dose be reduced by 50% in patients with mild to moderate hepatic impairment. Since there was much individual variability in clearance between patients with cirrhosis, it may be necessary to reduce the dose even more than 50%, and individualization of dosing may be desirable in some patients. Patients with Renal Impairment Given the decrease in clearance for venlafaxine and the increase in elimination half-life for both venlafaxine and ODV that is observed in patients with renal impairment (GFR = 10 to 70 mL/min) compared with normal subjects [ see Use in Specific Populations ( 8.7 ) and Clinical Pharmacology ( 12.3 ) ], it is recommended that the total daily dose be reduced by 25% to 50%. In patients undergoing hemodialysis, it is recommended that the total daily dose be reduced by 50%. Because there was much individual variability in clearance between patients with renal impairment, individualization of dosage may be desirable in some patients. Elderly Patients No dose adjustment is recommended for elderly patients solely on the basis of age. As with any drug for the treatment of major depressive disorder or Social Anxiety Disorder, however, caution should be exercised in treating the elderly. When individualizing the dosage, extra care should be taken when increasing the dose. 2.4 Discontinuing Venlafaxine Extended-Release Tablets Symptoms associated with discontinuation of venlafaxine hydrochloride extended-release capsules, other SNRI's, and SSRI's have been reported [ see Warnings and Precautions ( 5.5 ) ]. 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. In clinical trials with venlafaxine hydrochloride extended-release capsules, tapering was achieved by reducing the daily dose by 75 mg at 1 week intervals. Individualization of tapering may be necessary. 2.5 Switching Patients from Venlafaxine Hydrochloride Immediate-Release Tablets Depressed patients who are currently being treated at a therapeutic dose with venlafaxine hydrochloride immediate-release tablets may be switched to venlafaxine extended-release tablets at the nearest equivalent dose (mg/day), e.g., 37.5 mg venlafaxine two-times-a-day to 75 mg venlafaxine extended-release tablets once daily. However, individual dosage adjustments may be

WARNINGS Clinical Worsening and Suicide Risk Patients with major depressive disorder (MDD), both adult and pediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, 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 worsening of depression and the emergence of suicidality in certain patients during the early phases of treatment. Pooled analyses of short-term placebo-controlled trials of antidepressant drugs (SSRIs and others) showed that these drugs increase the risk of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults (ages 18 to 24) with major depressive disorder (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 age 24; there was a reduction with antidepressants compared to placebo in adults aged 65 and older. The pooled analyses of placebo-controlled trials in children and adolescents with MDD, obsessive compulsive disorder (OCD), or other psychiatric disorders included a total of 24 short-term trials of 9 antidepressant drugs in over 4400 patients. The pooled analyses of placebo-controlled trials in adults with MDD or other psychiatric disorders included a total of 295 short-term trials (median duration of 2 months) of 11 antidepressant drugs in over 77,000 patients. There was considerable variation in risk of suicidality among drugs, but a tendency toward an increase in the younger patients for almost all drugs studied. There were differences in absolute risk of suicidality across the different indications, with the highest incidence in MDD. The risk differences (drug vs. placebo), however, were relatively stable within age strata and across indications. These risk differences (drug-placebo difference in the number of cases of suicidality per 1000 patients treated) are provided in Table 1. Table 1 Age Range Drug - Placebo Difference in Number of Cases of Suicidality per 1000 Patients Treated Increases Compared to Placebo < 18 14 additional cases 18 to 24 5 additional cases Decreases Compared to Placebo 25 to 64 1 fewer case ≥ 65 6 fewer cases No suicides occurred in any of the pediatric trials. There were suicides in the adult trials, but the number was not sufficient to reach any conclusion about drug effect on suicide. 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 trials 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 behavior, 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 pediatric patients being treated with antidepressants for major depressive disorder as well as for other indications, both psychiatric and nonpsychiatric. 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 (see PRECAUTIONS and DOSAGE AND ADMINISTRATION : Discontinuation of Treatment with Venlafaxine Tablets , for a description of the risks of discontinuation of venlafaxine tablets). Families and caregivers of patients being treated with antidepressants for major depressive disorder or other indications, both psychiatric and nonpsychiatric, should be alerted about the need to monitor patients for the emergence of agitation, irritability, unusual changes in behavior, and the other symptoms described above, as well as the emergence of suicidality, and to report such symptoms immediately to health care providers. Such monitoring should include daily observation by families and caregivers. Prescriptions for venlafaxine tablets 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 trials) 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 venlafaxine tablets are not approved for use in treating bipolar depression. Serotonin Syndrome The development of a potentially life-threatening serotonin syndrome has been reported with SNRIs and SSRIs, including venlafaxine tablets, alone but particularly with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, amphetamines, and St. John's Wort) and with drugs that impair metabolism of serotonin (in particular, MAOIs, both those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue). Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular symptoms (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea). Patients should be monitored for the emergence of serotonin syndrome. The concomitant use of venlafaxine tablets with MAOIs intended to treat psychiatric disorders is contraindicated. Venlafaxine tablets should also not be started in a patient who is being treated with MAOIs such as linezolid or intravenous methylene blue. All reports with methylene blue that provided information on the route of administration involved intravenous administration in the dose range of 1 mg/kg to 8 mg/kg. No reports involved the administration of methylene blue by other routes (such as oral tablets or local tissue injection) or at lower doses. There may be circumstances when it is necessary to initiate treatment with a MAOI such as linezolid or intr

CONTRAINDICATIONS 4.1 Hypersensitivity Hypersensitivity to venlafaxine hydrochloride, desvenlafaxine succinate or to any excipients in the formulation 4.2 Concomitant Use with Monoamine Oxidase Inhibitors (MAOIs) The use of MAOIs (intended to treat psychiatric disorders) concomitantly with venlafaxine hydrochloride extended-release capsules or within 7 days of discontinuing treatment with venlafaxine hydrochloride extended-release capsules is contraindicated because of an increased risk of serotonin syndrome. The use of venlafaxine hydrochloride extended-release capsules within 14 days of discontinuing treatment with an MAOI (intended to treat psychiatric disorders) is also contraindicated [see Dosage and Administration (2.9), Warnings and Precautions (5.2), and Drug Interactions (7.2)]. Starting venlafaxine hydrochloride extended-release capsules in a patient who is being treated with an MAOI such as linezolid or intravenous methylene blue is also contraindicated, because of an increased risk of serotonin syndrome [see Dosage and Administration (2.9), Warnings and Precautions (5.2), and Drug Interactions (7.3)]. • Hypersensitivity to venlafaxine hydrochloride, desvenlafaxine succinate, or any excipients in the venlafaxine hydrochloride extended-release capsules formulation (4.1). • Do not use with an MAOI or within 14 days of stopping an MAOI. Allow 7 days after stopping venlafaxine hydrochloride extended-release capsules before starting an MAOI, because of the risk of serotonin syndrome (4.2, 5.2, 7.3). 4.1 Hypersensitivity Hypersensitivity to venlafaxine hydrochloride, desvenlafaxine succinate or to any excipients in the formulation 4.2 Concomitant Use with Monoamine Oxidase Inhibitors (MAOIs) The use of MAOIs (intended to treat psychiatric disorders) concomitantly with venlafaxine hydrochloride extended-release capsules or within 7 days of discontinuing treatment with venlafaxine hydrochloride extended-release capsules is contraindicated because of an increased risk of serotonin syndrome. The use of venlafaxine hydrochloride extended-release capsules within 14 days of discontinuing treatment with an MAOI (intended to treat psychiatric disorders) is also contraindicated [see Dosage and Administration (2.9), Warnings and Precautions (5.2), and Drug Interactions (7.2)]. Starting venlafaxine hydrochloride extended-release capsules in a patient who is being treated with an MAOI such as linezolid or intravenous methylene blue is also contraindicated, because of an increased risk of serotonin syndrome [see Dosage and Administration (2.9), Warnings and Precautions (5.2), and Drug Interactions (7.3)]. 4.1 Hypersensitivity Hypersensitivity to venlafaxine hydrochloride, desvenlafaxine succinate or to any excipients in the formulation 4.2 Concomitant Use with Monoamine Oxidase Inhibitors (MAOIs) The use of MAOIs (intended to treat psychiatric disorders) concomitantly with venlafaxine hydrochloride extended-release capsules or within 7 days of discontinuing treatment with venlafaxine hydrochloride extended-release capsules is contraindicated because of an increased risk of serotonin syndrome. The use of venlafaxine hydrochloride extended-release capsules within 14 days of discontinuing treatment with an MAOI (intended to treat psychiatric disorders) is also contraindicated [see Dosage and Administration (2.9), Warnings and Precautions (5.2), and Drug Interactions (7.2)]. Starting venlafaxine hydrochloride extended-release capsules in a patient who is being treated with an MAOI such as linezolid or intravenous methylene blue is also contraindicated, because of an increased risk of serotonin syndrome [see Dosage and Administration (2.9), Warnings and Precautions (5.2), and Drug Interactions (7.3)].

Drug Interactions As with all drugs, the potential for interaction by a variety of mechanisms is a possibility. Alcohol A single dose of ethanol (0.5 g/kg) had no effect on the pharmacokinetics of venlafaxine or ODV when venlafaxine was administered at 150 mg/day in 15 healthy male subjects. Additionally, administration of venlafaxine in a stable regimen did not exaggerate the psychomotor and psychometric effects induced by ethanol in these same subjects when they were not receiving venlafaxine. Cimetidine Concomitant administration of cimetidine and venlafaxine in a steady-state study for both drugs resulted in inhibition of first-pass metabolism of venlafaxine in 18 healthy subjects. The oral clearance of venlafaxine was reduced by about 43%, and the exposure (AUC) and maximum concentration (C max ) of the drug were increased by about 60%. However, coadministration of cimetidine had no apparent effect on the pharmacokinetics of ODV, which is present in much greater quantity in the circulation than is venlafaxine. The overall pharmacological activity of venlafaxine plus ODV is expected to increase only slightly, and no dosage adjustment should be necessary for most normal adults. However, for patients with preexisting hypertension, and for elderly patients or patients with hepatic dysfunction, the interaction associated with the concomitant use of venlafaxine and cimetidine is not known and potentially could be more pronounced. Therefore, caution is advised with such patients. Diazepam Under steady-state conditions for venlafaxine administered at 150 mg/day, a single 10 mg dose of diazepam did not appear to affect the pharmacokinetics of either venlafaxine or ODV in 18 healthy male subjects. Venlafaxine also did not have any effect on the pharmacokinetics of diazepam or its active metabolite, desmethyldiazepam, or affect the psychomotor and psychometric effects induced by diazepam. Haloperidol Venlafaxine administered under steady-state conditions at 150 mg/day in 24 healthy subjects decreased total oral-dose clearance (Cl/F) of a single 2 mg dose of haloperidol by 42%, which resulted in a 70% increase in haloperidol AUC. In addition, the haloperidol C max increased 88% when coadministered with venlafaxine, but the haloperidol elimination half-life (t 1/2 ) was unchanged. The mechanism explaining this finding is unknown. Lithium The steady-state pharmacokinetics of venlafaxine administered at 150 mg/day were not affected when a single 600 mg oral dose of lithium was administered to 12 healthy male subjects. O-desmethylvenlafaxine (ODV) also was unaffected. Venlafaxine had no effect on the pharmacokinetics of lithium (see also CNS-Active Drugs , below ). Drugs Highly Bound to Plasma Protein Venlafaxine is not highly bound to plasma proteins; therefore, administration of venlafaxine tablets to a patient taking another drug that is highly protein bound should not cause increased free concentrations of the other drug. Drugs that Interfere with Hemostasis (e.g., NSAIDs, Aspirin, and Warfarin) Serotonin release by platelets plays an important role in hemostasis. Epidemiological studies of the case-control and cohort design that have demonstrated an association between use of psychotropic drugs that interfere with serotonin reuptake and the occurrence of upper gastrointestinal bleeding have also shown that concurrent use of an NSAID or aspirin may potentiate this risk of bleeding. Altered anticoagulant effects, including increased bleeding, have been reported when SSRIs and SNRIs are coadministered with warfarin. Patients receiving warfarin therapy should be carefully monitored when venlafaxine is initiated or discontinued. Drugs that Inhibit Cytochrome P450 Isoenzymes CYP2D6 Inhibitors: In vitro and in vivo studies indicate that venlafaxine is metabolized to its active metabolite, ODV, by CYP2D6, the isoenzyme that is responsible for the genetic polymorphism seen in the metabolism of many antidepressants. Therefore, the potential exists for a drug interaction between drugs that inhibit CYP2D6-mediated metabolism and venlafaxine. However, although imipramine partially inhibited the CYP2D6-mediated metabolism of venlafaxine, resulting in higher plasma concentrations of venlafaxine and lower plasma concentrations of ODV, the total concentration of active compounds (venlafaxine plus ODV) was not affected. Additionally, in a clinical study involving CYP2D6-poor and -extensive metabolizers, the total concentration of active compounds (venlafaxine plus ODV), was similar in the two metabolizer groups. Therefore, no dosage adjustment is required when venlafaxine is coadministered with a CYP2D6 inhibitor. Ketoconazole A pharmacokinetic study with ketoconazole 100 mg b.i.d. with a single dose of venlafaxine 50 mg in extensive metabolizers (EM; n = 14) and 25 mg in poor metabolizers (PM; n = 6) of CYP2D6 resulted in higher plasma concentrations of both venlafaxine and O-desvenlafaxine (ODV) in most subjects following administration of ketoconazole. Venlafaxine C max increased by 26% in EM subjects and 48% in PM subjects. C max values for ODV increased by 14% and 29% in EM and PM subjects, respectively. Venlafaxine AUC increased by 21% in EM subjects and 70% in PM subjects (range in PMs - 2% to 206%), and AUC values for ODV increased by 23% and 33% in EM and PM subjects (range in PMs - 38% to 105%) subjects, respectively. Combined AUCs of venlafaxine and ODV increased on average by approximately 23% in EMS and 53% in PMs (range in PMs – 4% to 134%). Concomitant use of CYP3A4 inhibitors and venlafaxine may increase levels of venlafaxine and ODV. Therefore, caution is advised if a patient's therapy includes a CYP3A4 inhibitor and venlafaxine concomitantly. CYP3A4 Inhibitors In vitro studies indicate that venlafaxine is likely metabolized to a minor, less active metabolite, N-desmethylvenlafaxine, by CYP3A4. Because CYP3A4 is typically a minor pathway relative to CYP2D6 in the metabolism of venlafaxine, the potential for a clinically significant drug interaction between drugs that inhibit CYP3A4-mediated metabolism and venlafaxine is small. The concomitant use of venlafaxine with a drug treatment(s) that potently inhibits both CYP2D6 and CYP3A4, the primary metabolizing enzymes for venlafaxine, has not been studied. Therefore, caution is advised should a patient's therapy include venlafaxine and any agent(s) that produce potent simultaneous inhibition of these two enzyme systems. Drugs Metabolized by Cytochrome P450 Isoenzymes CYP2D6: In vitro studies indicate that venlafaxine is a relatively weak inhibitor of CYP2D6. These findings have been confirmed in a clinical drug interaction study comparing the effect of venlafaxine to that of fluoxetine on the CYP2D6-mediated metabolism of dextromethorphan to dextrorphan. Imipramine Venlafaxine did not affect the pharmacokinetics of imipramine and 2-OH-imipramine. However, desipramine AUC, C max , and C min increased by about 35% in the presence of venlafaxine. The 2-OH-desipramine AUCs increased by at least 2.5 fold (with venlafaxine 37.5 mg q12h) and by 4.5 fold (with venlafaxine 75 mg q12h). Imipramine did not affect the pharmacokinetics of venlafaxine and ODV. The clinical significance of elevated 2-OH-desipramine levels is unknown. Metoprolol Concomitant administration of venlafaxine (50 mg every 8 hours for 5 days) and metoprolol (100 mg every 24 hours for 5 days) to 18 healthy male subjects in a pharmacokinetic interaction study for both drugs resulted in an increase of plasma concentrations of metoprolol by approximately 30 to 40% without altering the plasma concentrations of its active metabolite, α-hydroxymetoprolol. Metoprolol did not alter the pharmacokinetic profile of venlafaxine or its active metabolite, O-desmethylvenlafaxine. Venlafaxine appeared to reduce the blood pressure lowering effect of metoprolol in this study. The clinical relevance of this finding for hypertensive patients is unknown. Caution should

ADVERSE REACTIONS Associated with Discontinuation of Treatment Nineteen percent (537/2897) of venlafaxine patients in Phase 2 and Phase 3 depression studies discontinued treatment due to an adverse event. The more common events (≥ 1%) associated with discontinuation and considered to be drug-related (i.e., those events associated with dropout at a rate approximately twice or greater for venlafaxine compared to placebo) included: CNS Venlafaxine Placebo * Percentages based on the number of males. — Less than 1% Somnolence 3% 1% Insomnia 3% 1% Dizziness 3% − Nervousness 2% − Dry mouth 2% − Anxiety 2% 1% Gastrointestinal Nausea 6% 1% Urogenital Abnormal 3% − ejaculation * Other Headache 3% 1% Asthenia 2% − Sweating 2% − Incidence in Controlled Trials Commonly Observed Adverse Events in Controlled Clinical Trials The most commonly observed adverse events associated with the use of venlafaxine tablets (incidence of 5% or greater) and not seen at an equivalent incidence among placebo-treated patients (i.e., incidence for venlafaxine tablets at least twice that for placebo), derived from the 1% incidence table below, were asthenia, sweating, nausea, constipation, anorexia, vomiting, somnolence, dry mouth, dizziness, nervousness, anxiety, tremor, and blurred vision as well as abnormal ejaculation/orgasm and impotence in men. Adverse Events Occurring at an Incidence of 1% or More Among Venlafaxine Tablets -Treated Patients The table that follows enumerates adverse events that occurred at an incidence of 1% or more, and were more frequent than in the placebo group, among venlafaxine tablets-treated patients who participated in short-term (4 to 8 week) placebo-controlled trials in which patients were administered doses in a range of 75 to 375 mg/day. This table shows the percentage of patients in each group who had at least one episode of an event at some time during their treatment. Reported adverse events were classified using a standard COSTART-based Dictionary terminology. The prescriber should be aware that these figures cannot be used to predict the incidence of side effects in the course of usual medical practice where patient characteristics and other factors differ from those which prevailed in the clinical trials. Similarly, the cited frequencies cannot be compared with figures obtained from other clinical investigations involving different treatments, uses and investigators. The cited figures, however, do provide the prescribing physician with some basis for estimating the relative contribution of drug and nondrug factors to the side effect incidence rate in the population studied. TABLE 2 Treatment-Emergent Adverse Experience Incidence in 4 to 8 Week Placebo-Controlled Clinical Trials 1 1 Events reported by at least 1% of patients treated with venlafaxine tablets are included, and are rounded to the nearest %. Events for which the venlafaxine tablets incidence was equal to or less than placebo are not listed in the table, but included the following: abdominal pain, pain, back pain, flu syndrome, fever, palpitation, increased appetite, myalgia, arthralgia, amnesia, hypesthesia, rhinitis, pharyngitis, sinusitis, cough increased, and dysmenorrhea 3 . — Incidence less than 1%. 2 Incidence based on number of male patients. 3 Incidence based on number of female patients. Body System Preferred Term Venlafaxine Tablets Placebo (n=1033) (n=609) Body as a Whole Headache 25% 24% Asthenia 12% 6% Infection 6% 5% Chills 3% — Chest pain 2% 1% Trauma 2% 1% Cardiovascular Vasodilatation 4% 3% Increased blood pressure/hypertension 2% — Tachycardia 2% — Postural hypotension 1% — Dermatological Sweating 12% 3% Rash 3% 2% Pruritus 1% — Gastrointestinal Nausea 37% 11% Constipation 15% 7% Anorexia 11% 2% Diarrhea 8% 7% Vomiting 6% 2% Dyspepsia 5% 4% Flatulence 3% 2% Metabolic Weight loss 1% __ Nervous System Somnolence 23% 9% Dry mouth 22% 11% Dizziness 19% 7% Insomnia 18% 10% Nervousness 13% 6% Anxiety 6% 3% Tremor 5% 1% Abnormal dreams 4% 3% Hypertonia 3% 2% Paresthesia 3% 2% Libido decreased 2% — Agitation 2% — Confusion 2% 1% Thinking abnormal 2% 1% Depersonalization 1% — Depression 1% — Urinary retention 1% — Twitching 1% — Respiration Yawn 3% — Special Senses Blurred vision 6% 2% Taste perversion 2% — Tinnitus 2% — Mydriasis 2% — Urogenital System Abnormal ejaculation/orgasm 12% 2 — 2 Impotence 6 % 2 — 2 Urinary frequency 3% 2% Urination impaired 2% — Orgasm disturbance 2% 3 — 3 Dose Dependency of Adverse Events A comparison of adverse event rates in a fixed-dose study comparing venlafaxine tablets 75, 225, and 375 mg/day with placebo revealed a dose dependency for some of the more common adverse events associated with venlafaxine tablets use, as shown in the table that follows. The rule for including events was to enumerate those that occurred at an incidence of 5% or more for at least one of the venlafaxine groups and for which the incidence was at least twice the placebo incidence for at least one venlafaxine tablets group. Tests for potential dose relationships for these events (Cochran-Armitage Test, with a criterion of exact 2-sided p-value ≤ 0.05) suggested a dose-dependency for several adverse events in this list, including chills, hypertension, anorexia, nausea, agitation, dizziness, somnolence, tremor, yawning, sweating, and abnormal ejaculation. TABLE 3 Treatment-Emergent Adverse Experience Incidence in a Dose Comparison Trial $NoTableFooter $NoFootNote Venlafaxine Tablets (mg/day) Body System/ Preferred Term Placebo 75 225 375 (n=92) (n=89) (n=89) (n=88) Body as a Whole Abdominal pain 3.3% 3.4% 2.2% 8% Asthenia 3.3% 16.9% 14.6% 14.8% Chills 1.1% 2.2% 5.6% 6.8% Infection 2.2% 2.2% 5.6% 2.3% Cardiovascular System Hypertension 1.1% 1.1% 2.2% 4.5% Vasodilatation 0% 4.5% 5.6% 2.3% Digestive System Anorexia 2.2% 14.6% 13.5% 17% Dyspepsia 2.2% 6.7% 6.7% 4.5% Nausea 14.1% 32.6% 38.2% 58% Vomiting 1.1% 7.9% 3.4% 6.8% Nervous System Agitation 0% 1.1% 2.2% 4.5% Anxiety 4.3% 11.2% 4.5% 2.3% Dizziness 4.3% 19.1% 22.5% 23.9% Insomnia 9.8% 22.5% 20.2% 13.6% Libido decreased 1.1% 2.2% 1.1% 5.7% Nervousness 4.3% 21.3% 13.5% 12.5% Somnolence 4.3% 16.9% 18% 26.1% Tremor 0% 1.1% 2.2% 10.2% Respiratory System Yawn 0% 4.5% 5.6% 8% Skin and Appendages Sweating 5.4% 6.7% 12.4% 19.3% Special Senses Abnormality of accommodation 0% 9.1% 7.9% 5.6% Urogenital System Abnormal ejaculation/orgasm 0% 4.5% 2.2% 12.5% Impotence 0% 5.8% 2.1% 3.6% (Number of men) (n=63) (n=52) (n=48) (n=56) Adaptation to Certain Adverse Events Over a 6 week period, there was evidence of adaptation to some adverse events with continued therapy (e.g., dizziness and nausea), but less to other effects (e.g., abnormal ejaculation and dry mouth). Vital Sign Changes Venlafaxine tablets treatment (averaged over all dose groups) in clinical trials was associated with a mean increase in pulse rate of approximately 3 beats per minute, compared to no change for placebo. In a flexible-dose study, with doses in the range of 200 to 375 mg/day and mean dose greater than 300 mg/day, the mean pulse was increased by about 2 beats per minute compared with a decrease of about 1 beat per minute for placebo. In controlled clinical trials, venlafaxine tablets were associated with mean increases in diastolic blood pressure ranging from 0.7 to 2.5 mm Hg averaged over all dose groups, compared to mean decreases ranging from 0.9 to 3.8 mm Hg for placebo. However, there is a dose dependency for blood pressure increase (see WARNINGS). Laboratory Changes Of the serum chemistry and hematology parameters monitored during clinical trials with venlafaxine tablets, a statistically significant difference with placebo was seen only for serum cholesterol. In premarketing trials, treatment with venlafaxine tablets was associated with a mean final on-therapy increase in total cholesterol of 3 mg/dL. Patients treated with venlafaxine tablets for at least 3 months in placebo-controlled 12 month extension trials had a mean final on-therapy increase

CLINICAL PHARMACOLOGY Pharmacodynamics The mechanism of the antidepressant action of venlafaxine in humans is believed to be associated with its potentiation of neurotransmitter activity in the CNS. Preclinical studies have shown that venlafaxine and its active metabolite, O-desmethylvenlafaxine (ODV), are potent inhibitors of neuronal serotonin and norepinephrine reuptake and weak inhibitors of dopamine reuptake. Venlafaxine and ODV have no significant affinity for muscarinic, histaminergic, or α-1 adrenergic receptors in vitro . Pharmacologic activity at these receptors is hypothesized to be associated with the various anticholinergic, sedative, and cardiovascular effects seen with other psychotropic drugs. Venlafaxine and ODV do not possess monoamine oxidase (MAO) inhibitory activity. Pharmacokinetics Venlafaxine is well absorbed and extensively metabolized in the liver. O-desmethylvenlafaxine (ODV) is the only major active metabolite. On the basis of mass balance studies, at least 92% of a single dose of venlafaxine is absorbed. Approximately 87% of a venlafaxine dose is recovered in the urine within 48 hours as either unchanged venlafaxine (5%), unconjugated ODV (29%), conjugated ODV (26%), or other minor inactive metabolites (27%). Renal elimination of venlafaxine and its metabolites is the primary route of excretion. The relative bioavailability of venlafaxine from a tablet was 100% when compared to an oral solution. Food has no significant effect on the absorption of venlafaxine or on the formation of ODV. The degree of binding of venlafaxine to human plasma is 27% ± 2% at concentrations ranging from 2.5 to 2215 ng/mL. The degree of ODV binding to human plasma is 30% ± 12% at concentrations ranging from 100 to 500 ng/mL. Protein-binding-induced drug interactions with venlafaxine are not expected. Steady-state concentrations of both venlafaxine and ODV in plasma were attained within 3 days of multiple-dose therapy. Venlafaxine and ODV exhibited linear kinetics over the dose range of 75 to 450 mg total dose per day (administered on a q8h schedule). Plasma clearance, elimination half-life and steady-state volume of distribution were unaltered for both venlafaxine and ODV after multiple-dosing. Mean ± SD steady-state plasma clearance of venlafaxine and ODV is 1.3 ± 0.6 and 0.4 ± 0.2 L/h/kg, respectively; elimination half-life is 5 ± 2 and 11±2 hours, respectively; and steady-state volume of distribution is 7.5 ± 3.7 L/kg and 5.7 ± 1.8 L/kg, respectively. When equal daily doses of venlafaxine were administered as either b.i.d. or t.i.d. regimens, the drug exposure (AUC) and fluctuation in plasma levels of venlafaxine and ODV were comparable following both regimens. Age and Gender A pharmacokinetic analysis of 404 venlafaxine-treated patients from two studies involving both b.i.d. and t.i.d. regimens showed that dose-normalized trough plasma levels of either venlafaxine or ODV were unaltered due to age or gender differences. Dosage adjustment based upon the age or gender of a patient is generally not necessary (see DOSAGE AND ADMINISTRATION ). Liver Disease In 9 subjects with hepatic cirrhosis, the pharmacokinetic disposition of both venlafaxine and ODV was significantly altered after oral administration of venlafaxine. Venlafaxine elimination half-life was prolonged by about 30%, and clearance decreased by about 50% in cirrhotic subjects compared to normal subjects. ODV elimination half-life was prolonged by about 60% and clearance decreased by about 30% in cirrhotic subjects compared to normal subjects. A large degree of intersubject variability was noted. Three patients with more severe cirrhosis had a more substantial decrease in venlafaxine clearance (about 90%) compared to normal subjects. In a second study, venlafaxine was administered orally and intravenously in normal (n = 21) subjects, and in Child-Pugh A (n = 8) and Child-Pugh B (n = 11) subjects (mildly and moderately impaired, respectively). Venlafaxine oral bioavailability was increased 2 to 3 fold, oral elimination half-life was approximately twice as long and oral clearance was reduced by more than half, compared to normal subjects. In hepatically impaired subjects, ODV oral elimination half-life was prolonged by about 40%, while oral clearance for ODV was similar to that for normal subjects. A large degree of intersubject variability was noted. Dosage adjustment is necessary in these hepatically impaired patients (see DOSAGE AND ADMINISTRATION ). Renal Disease In a renal impairment study, venlafaxine elimination half-life after oral administration was prolonged by about 50% and clearance was reduced by about 24% in renally impaired patients (GFR = 10 to 70 mL/min), compared to normal subjects. In dialysis patients, venlafaxine elimination half-life was prolonged by about 180% and clearance was reduced by about 57% compared to normal subjects. Similarly, ODV elimination half-life was prolonged by about 40% although clearance was unchanged in patients with renal impairment (GFR = 10 to 70 mL/min) compared to normal subjects. In dialysis patients, ODV elimination half-life was prolonged by about 142% and clearance was reduced by about 56%, compared to normal subjects. A large degree of intersubject variability was noted. Dosage adjustment is necessary in these patients (see DOSAGE AND ADMINISTRATION ). CLINICAL TRIALS The efficacy of venlafaxine tablets as a treatment for major depressive disorder was established in 5 placebo-controlled, short-term trials. Four of these were 6 week trials in adult outpatients meeting DSM-III or DSM-III-R criteria for major depression: two involving dose titration with venlafaxine tablets in a range of 75 to 225 mg/day (t.i.d. schedule), the third involving fixed venlafaxine tablets doses of 75, 225, and 375 mg/day (t.i.d. schedule), and the fourth involving doses of 25, 75, and 200 mg/day (b.i.d. schedule). The fifth was a 4 week study of adult inpatients meeting DSM-III-R criteria for major depression with melancholia whose venlafaxine tablets doses were titrated in a range of 150 to 375 mg/day (t.i.d. schedule). In these 5 studies, venlafaxine tablets were shown to be significantly superior to placebo on at least 2 of the following 3 measures: Hamilton Depression Rating Scale (total score), Hamilton depressed mood item, and Clinical Global Impression-Severity of Illness rating. Doses from 75 to 225 mg/day were superior to placebo in outpatient studies and a mean dose of about 350 mg/day was effective in inpatients. Data from the 2 fixed-dose outpatient studies were suggestive of a dose-response relationship in the range of 75 to 225 mg/day. There was no suggestion of increased response with doses greater than 225 mg/day. While there were no efficacy studies focusing specifically on an elderly population, elderly patients were included among the patients studied. Overall, approximately 2/3 of all patients in these trials were women. Exploratory analyses for age and gender effects on outcome did not suggest any differential responsiveness on the basis of age or sex. In one longer-term study, adult outpatients meeting DSM-IV criteria for major depressive disorder who had responded during an 8 week open trial on venlafaxine hydrochloride extended-release capsules (75, 150, or 225 mg, qAM) were randomized to continuation of their same venlafaxine hydrochloride extended-release capsules dose or to placebo, for up to 26 weeks of observation for relapse. Response during the open phase was defined as a CGI Severity of Illness item score of ≤ 3 and a HAM-D-21 total score of ≤ 10 at the day 56 evaluation. Relapse during the doubleblind phase was defined as follows: (1) a reappearance of major depressive disorder as defined by DSM-IV criteria and a CGI Severity of Illness item score of ≥ 4 (moderately ill), (2) 2 consecutive CGI Severity of Illness item scores of ≥ 4, or (3) a final CGI Severity of Illness item score of ≥ 4 for any patient who withdrew from t