Desvenlafaxine

12.1 Mechanism of Action The exact mechanism of the antidepressant action of desvenlafaxine is unknown, but is thought to be related to the potentiation of serotonin and norepinephrine in the central nervous system, through inhibition of their reuptake. Non-clinical studies have shown that desvenlafaxine is a potent and selective SNRI.

1 INDICATIONS AND USAGE PRISTIQ is indicated for the treatment of adults with major depressive disorder (MDD) [see Clinical Studies (14) ] . PRISTIQ is a serotonin and norepinephrine reuptake inhibitor (SNRI) indicated for the treatment of adults with major depressive disorder (MDD) ( 1 ).

2 DOSAGE AND ADMINISTRATION • Recommended dose: 50 mg once daily with or without food ( 2.1 ). • There was no evidence that doses greater than 50 mg per day confer any additional benefit ( 2.1 ). • The 25 mg per day dose is intended for a gradual reduction in dose when discontinuing treatment or dosing in severe renal and end-stage renal disease patients ( 2.1 ). • Discontinuation: Reduce dose gradually whenever possible ( 2.1 ). • Take tablets whole; do not divide, crush, chew, or dissolve ( 2.1 ). • Moderate renal impairment: Maximum dose 50 mg per day ( 2.2 ). • Severe renal impairment and end-stage renal disease: Maximum dose 25 mg per day or 50 mg every other day ( 2.2 ). • Moderate to severe hepatic impairment: Maximum dose 100 mg per day ( 2.3 ). 2.1 General Instructions for Use The recommended dose for PRISTIQ is 50 mg once daily, with or without food. The 50 mg dose is both a starting dose and the therapeutic dose. PRISTIQ should be taken at approximately the same time each day. Tablets must be swallowed whole with fluid and not divided, crushed, chewed, or dissolved. In clinical studies, doses of 10 mg to 400 mg per day were studied. In clinical studies, doses of 50 mg to 400 mg per day were shown to be effective, although no additional benefit was demonstrated at doses greater than 50 mg per day and adverse reactions and discontinuations were more frequent at higher doses. The 25 mg per day dose is intended for a gradual reduction in dose when discontinuing treatment. When discontinuing therapy, gradual dose reduction is recommended whenever possible to minimize discontinuation symptoms [see Dosage and Administration (2.5) and Warnings and Precautions (5.7) ] . 2.2 Dosage Recommendations for Patients with Renal Impairment The maximum recommended dose in patients with moderate renal impairment (24-hr creatinine clearance [Cl Cr ] = 30 to 50 mL/min, Cockcroft-Gault [C-G]) is 50 mg per day. The maximum recommended dose in patients with severe renal impairment (Cl Cr 15 to 29 mL/min, C-G) or end-stage renal disease (ESRD, Cl Cr < 15 mL/min, C-G) is 25 mg every day or 50 mg every other day. Supplemental doses should not be given to patients after dialysis [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ] . 2.3 Dosage Recommendations for Patients with Hepatic Impairment The recommended dose in patients with moderate to severe hepatic impairment (Child-Pugh score 7 to 15) is 50 mg per day. Dose escalation above 100 mg per day is not recommended [see Use in Specific Populations (8.7) and Clinical Pharmacology (12.3) ] . 2.4 Maintenance/Continuation/Extended Treatment It is generally agreed that acute episodes of major depressive disorder require several months or longer of sustained pharmacologic therapy. Longer-term efficacy of PRISTIQ (50–400 mg) was established in two maintenance trials [see Clinical Studies (14) ] . Patients should be periodically reassessed to determine the need for continued treatment. 2.5 Discontinuing PRISTIQ Adverse reactions may occur upon discontinuation of PRISTIQ [see Warnings and Precautions (5.7) ]. Gradually reduce the dosage rather than stopping PRISTIQ abruptly when discontinuing therapy with PRISTIQ. In some patients, discontinuation may need to occur over a period of several months. 2.6 Switching Patients From Other Antidepressants to PRISTIQ Discontinuation symptoms have been reported when switching patients from other antidepressants, including venlafaxine, to PRISTIQ. Tapering of the initial antidepressant may be necessary to minimize discontinuation symptoms. 2.7 Switching Patients to or from a Monoamine Oxidase Inhibitor (MAOI) Intended to Treat Psychiatric Disorders At least 14 days should elapse between discontinuation of an MAOI intended to treat psychiatric disorders and initiation of therapy with PRISTIQ. Conversely, at least 7 days should be allowed after stopping PRISTIQ before starting an MAOI intended to treat psychiatric disorders [see Contraindications (4) ] . 2.8 Use of PRISTIQ with other MAOIs such as Linezolid or Methylene Blue Do not start PRISTIQ in a patient who is being treated with linezolid or intravenous methylene blue because there is increased risk of serotonin syndrome. In a patient who requires more urgent treatment of a psychiatric condition, other interventions, including hospitalization, should be considered [see Contraindications (4) ] . In some cases, a patient already receiving PRISTIQ therapy may require urgent treatment with linezolid or intravenous methylene blue. If acceptable alternatives to linezolid or intravenous methylene blue treatment are not available and the potential benefits of linezolid or intravenous methylene blue treatment are judged to outweigh the risks of serotonin syndrome in a particular patient, PRISTIQ should be stopped promptly, and linezolid or intravenous methylene blue can be administered. The patient should be monitored for symptoms of serotonin syndrome for 7 days or until 24 h

6 ADVERSE REACTIONS The following adverse reactions are discussed in greater detail in other sections of the label. • Hypersensitivity [see Contraindications (4) ] • Suicidal Thoughts and Behaviors in Pediatric and Young Adult Patients [see Warnings and Precautions (5.1) ] • Serotonin Syndrome [see Warnings and Precautions (5.2) ] • Elevated Blood Pressure [see Warnings and Precautions (5.3) ] • Increased Risk of Bleeding [see Warnings and Precautions (5.4) ] • Angle Closure Glaucoma [see Warnings and Precautions (5.5) ] • Activation of Mania/Hypomania [see Warnings and Precautions (5.6) ] • Discontinuation Syndrome [see Warnings and Precautions (5.7) ] • Seizure [see Warnings and Precautions (5.8) ] • Hyponatremia [see Warnings and Precautions (5.9) ] • Interstitial Lung Disease and Eosinophilic Pneumonia [see Warnings and Precautions (5.10) ] • Sexual Dysfunction [see Warnings and Precautions (5.11) ] Most common adverse reactions (incidence ≥5% and 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 ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Wyeth Pharmaceuticals LLC, a subsidiary of Pfizer Inc., at 1-800-438-1985 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Studies Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in clinical practice. Patient Exposure PRISTIQ was evaluated for safety in 8,394 patients diagnosed with major depressive disorder who participated in multiple-dose pre-marketing studies, representing 2,784 patient-years of exposure. Of the total 8,394 patients exposed to at least one dose of PRISTIQ; 2,116 were exposed to PRISTIQ for 6 months, representing 1,658 patient-years of exposure, and 421 were exposed for one year, representing 416 patient-years of exposure. Adverse Reactions Reported as Reasons for Discontinuation of Treatment In the pre-marketing pooled 8-week placebo-controlled studies in patients with MDD, 1,834 patients were exposed to PRISTIQ (50 to 400 mg). Of the 1,834 patients, 12% discontinued treatment due to an adverse reaction, compared with 3% of the 1,116 placebo-treated patients. At the recommended dose of 50 mg, the discontinuation rate due to an adverse reaction for PRISTIQ (4.1%) was similar to the rate for placebo (3.8%). For the 100 mg dose of PRISTIQ the discontinuation rate due to an adverse reaction was 8.7%. The most common adverse reactions leading to discontinuation in at least 2% and at a rate greater than placebo of the PRISTIQ treated patients in the short-term studies, up to 8 weeks, were: nausea (4%); dizziness, headache and vomiting (2% each). In a longer-term study, up to 9 months, the most common was vomiting (2%). Common Adverse Reactions in Placebo-Controlled MDD Studies The most commonly observed adverse reactions in PRISTIQ treated MDD patients in pre-marketing pooled 8-week, placebo-controlled, 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. Table 2 shows the incidence of common adverse reactions that occurred in ≥ 2% of PRISTIQ treated MDD patients and twice the rate of placebo at any dose in the pre-marketing pooled 8-week, placebo-controlled, fixed dose clinical studies. Table 2: Common Adverse Reactions (≥ 2% in any Fixed-Dose Group and Twice the Rate of Placebo) in Pre-marketing Pooled MDD 8-Week Placebo-Controlled Studies Percentage of Patients Reporting Reaction PRISTIQ System Organ Class Preferred Term Placebo (n=636) 50 mg (n=317) 100 mg (n=424) 200 mg (n=307) 400 mg (n=317) Cardiac disorders Blood pressure increased 1 1 1 2 2 Gastrointestinal disorders Nausea 10 22 26 36 41 Dry mouth 9 11 17 21 25 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 Metabolism and nutrition disorders Decreased appetite 2 5 8 10 10 Nervous system disorders Dizziness 5 13 10 15 16 Somnolence 4 4 9 12 12 Tremor 2 2 3 9 9 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 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 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 Sexual Function Adverse Reactions Table 3

7 DRUG INTERACTIONS 7.1 Drugs Having Clinically Important Interactions with PRISTIQ Table 8: Clinically Important Drug Interactions with PRISTIQ Monoamine Oxidase Inhibitors (MAOI) Clinical Impact The concomitant use of SSRIs and SNRIs including PRISTIQ with MAOIs increases the risk of serotonin syndrome. Intervention Concomitant use of PRISTIQ is contraindicated: • With an MAOI intended to treat psychiatric disorders or within 7 days of stopping treatment with PRISTIQ. • Within 14 days of stopping an MAOI intended to treat psychiatric disorders. • In a patient who is being treated with linezolid or intravenous methylene blue. [see Dosage and Administration (2.7) , Contraindications (4) and Warnings and Precautions (5.2) ]. Examples selegiline, tranylcypromine, isocarboxazid, phenelzine, linezolid, methylene blue Other Serotonergic Drugs Clinical Impact Concomitant use of PRISTIQ with other serotonergic drugs increases the risk of serotonin syndrome. Intervention Monitor for symptoms of serotonin syndrome when PRISTIQ is used concomitantly with other drugs that may affect the serotonergic neurotransmitter systems. If serotonin syndrome occurs, consider discontinuation of PRISTIQ and/or concomitant serotonergic drugs [see Warnings and Precautions (5.2) ]. Examples other SNRIs, SSRIs, triptans, tricyclic antidepressants, opioids, lithium, buspirone, amphetamines, tryptophan, and St. John's Wort Drugs that Interfere with Hemostasis Clinical Impact Concomitant use of PRISTIQ with an antiplatelet or anticoagulant drug may potentiate the risk of bleeding. This may be due to the effect of PRISTIQ on the release of serotonin by platelets. Intervention Closely monitor for bleeding for patients receiving an antiplatelet or anticoagulant drug when PRISTIQ is initiated or discontinued [see Warnings and Precautions (5.4) ] . Examples NSAIDs, aspirin, and warfarin Drugs that are Primarily Metabolized by CYP2D6 Clinical Impact Concomitant use of PRISTIQ increases C max and AUC of a drug primarily metabolized by CYP2D6 which may increase the risk of toxicity of the CYP2D6 substrate drug [see Clinical Pharmacology (12.3) ] . Intervention Original dose should be taken when co-administered with PRISTIQ 100 mg or lower. Reduce the dose of these drugs by up to one-half if co-administered with 400 mg of PRISTIQ. Examples desipramine, atomoxetine, dextromethorphan, metoprolol, nebivolol, perphenazine, tolterodine 7.2 Drugs Having No Clinically Important Interactions with PRISTIQ Based on pharmacokinetic studies, no dosage adjustment is required for drugs that are mainly metabolized by CYP3A4 (e.g., midazolam), or for drugs that are metabolized by both CYP2D6 and CYP3A4 (e.g., tamoxifen, aripiprazole), when administered concomitantly with PRISTIQ [see Clinical Pharmacology (12.3) ]. 7.3 Alcohol A clinical study has shown that PRISTIQ 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 PRISTIQ. 7.4 Drug-Laboratory Test Interactions False-positive urine immunoassay screening tests for phencyclidine (PCP) and amphetamine have been reported in patients taking desvenlafaxine. This is due to lack of specificity of the screening tests. False positive test results may be expected for several days following discontinuation of desvenlafaxine therapy. Confirmatory tests, such as gas chromatography/mass spectrometry, will distinguish desvenlafaxine from PCP and amphetamine.