Fluvoxamine

12.1 Mechanism of Action The mechanism of action of fluvoxamine maleate in obsessive compulsive disorder is presumed to be linked to its specific serotonin reuptake inhibition in brain neurons. Fluvoxamine has been shown to be a potent inhibitor of the serotonin reuptake transporter in preclinical studies, both in vitro and in vivo .

1 INDICATIONS AND USAGE Fluvoxamine maleate extended-release capsules is a selective serotonin reuptake inhibitor (SSRI) indicated for the treatment of obsessive compulsive disorder (OCD) ( 1 ). Efficacy was demonstrated in: One 12-week study fluvoxamine maleate extended-release capsules in adults ( 14.1 ). Two 10-week studies with immediate-release (IR) fluvoxamine tablets in adults and one 10-week study with IR fluvoxamine tablets in children and adolescents ( 14.1 , 14.3 ). One maintenance study with IR fluvoxamine tablets ( 14.2 ). 1.1 Obsessive Compulsive Disorder Fluvoxamine maleate extended-release capsules are indicated for the treatment of obsessive compulsive disorder (OCD), as defined in the DSM-IV. Obsessive compulsive disorder is characterized by recurrent and persistent ideas, thoughts, impulses, or images (obsessions) that are ego-dystonic and/or repetitive, purposeful, and intentional behaviors (compulsions) that are recognized by the person as excessive or unreasonable. The obsessions or compulsions cause marked distress, are time-consuming, or significantly interfere with social or occupational functioning. The efficacy of fluvoxamine maleate extended-release capsules was demonstrated in one 12-week trial in adults with fluvoxamine maleate extended-release capsules as well as in two 10-week trials in adults and in one 10-week trial in children and adolescents (ages 8 years to 17 years) with immediate-release fluvoxamine tablets in outpatients with the diagnosis of OCD as defined in DSM-IV or DSM-III-R (see CLINICAL STUDIES [ 14.1 , 14.3 ]). The efficacy of fluvoxamine for long-term use was established in one maintenance study in adults with immediate-release fluvoxamine tablets (see CLINICAL STUDIES [ 14.2 ]). The health care provider who elects to prescribe fluvoxamine maleate extended-release capsules for extended periods should periodically re-evaluate the long-term usefulness of the drug for the individual patient (see DOSAGE AND ADMINISTRATION

2 DOSAGE AND ADMINISTRATION Adults: Recommended starting dose is 100 mg at bedtime, with weekly increases of 50 mg as tolerated to maximum effect, not to exceed 300 mg/day ( 2.1 ) . Pediatric patients naïve to fluvoxamine maleate: The lowest available dose of fluvoxamine maleate extended-release capsules may not be appropriate ( 2.2 ) . Hepatically impaired: Decreased clearance may require modified dose and titration ( 2.3 ) . Extended treatment: Adjust dose to maintain lowest effective dose; reassess patients periodically ( 2.4 ) . Discontinuation: Gradual dose reduction is recommended ( 2.7 , see Warnings and Precautions [ 5.10 ] ). 2.1 OCD (Obsessive Compulsive Disorder) The recommended starting dose is 100 mg at bedtime, with weekly increases of 50 mg as tolerated to maximum therapeutic benefit, not to exceed 300 mg per day. Capsules should not be crushed or chewed. 2.2 Pediatric Patients Naïve to Fluvoxamine Maleate Physicians should consider that the lowest available dose of fluvoxamine maleate extended-release capsules may not be appropriate for pediatric patients naïve to fluvoxamine maleate. 2.3 Dosage for Elderly or Hepatically Impaired Patients Elderly patients and those with hepatic impairment have been observed to have a decreased clearance of fluvoxamine maleate. Consequently, it may be appropriate to titrate slowly following the initial dose of 100 mg in these patient groups. 2.4 Maintenance/Continuation of Extended Treatment Although the efficacy of fluvoxamine maleate extended-release capsules beyond 12 weeks of dosing has not been documented in controlled trials, OCD is a chronic condition, and it is reasonable to consider continuation for a responding patient. The benefit of maintaining patients with OCD on immediate-release fluvoxamine maleate tablets after achieving a response for an average duration of about 4 weeks in a 10-week single-blind phase during which patients were titrated to effect was demonstrated in a controlled trial ( see CLINICAL TRIALS [ 14.2 ] ).Dosage adjustments should be made to maintain the patient on the lowest effective dosage, and patients should be periodically reassessed to determine the need for continued treatment. 2.5 Switching a Patient 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 fluvoxamine maleate extended-release capsules. Conversely, at least 14 days should be allowed after stopping fluvoxamine maleate extended-release capsules before starting an MAOI intended to treat psychiatric disorders ( see CONTRAINDICATIONS [ 4.1 ] ). 2.6 Use of Fluvoxamine Maleate Extended-Release Capsules with Other MAOIs such as Linezolid or Methylene Blue Do not start fluvoxamine maleate extended-release capsules in a patient who is being treated with linezolid or intravenous methylene blue because there is an 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 [ 4.1 ] ) . In some cases, a patient already receiving fluvoxamine maleate extended-release 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, fluvoxamine maleate extended-release should be stopped promptly, and linezolid or intravenous methylene blue can be administered. The patient should be monitored for symptoms of serotonin syndrome for two weeks or until 24 hours after the last dose of linezolid or intravenous methylene blue, whichever comes first. Therapy with fluvoxamine maleate extended-release capsules may be resumed 24 hours after the last dose of linezolid or intravenous methylene blue ( see WARNINGS AND PRECAUTIONS [ 5.2 ] ) . The risk of administering methylene blue by non-intravenous routes (such as oral tablets or by local injection) or in intravenous doses much lower than 1 mg/kg with fluvoxamine maleate extended-release is unclear. The clinician should, nevertheless, be aware of the possibility of emergent symptoms of serotonin syndrome with such use ( see WARNINGS AND PRECAUTIONS [ 5.2 ] ) . 2.7 Discontinuation of Treatment with Fluvoxamine Maleate Extended-Release Capsules Symptoms associated with discontinuation of other SSRIs or SNRIs have been reported ( see WARNINGS AND PRECAUTIONS [ 5.10 ] ).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

6 ADVERSE REACTIONS 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 trials of another drug and may not reflect the rates observed in clinical practice. Most common reactions in controlled trials with OCD patients and patients from another studied population (incidence ≥5% and at least twice that for placebo) were abnormal ejaculation, anorexia, anorgasmia, asthenia, diarrhea, nausea, somnolence, sweating and tremor ( 6.2 ) . The following additional reactions occurred: anxiety, decreased libido, myalgia, pharyngitis, and vomiting in the OCD population; and dyspepsia, dizziness, insomnia, and yawning in another studied population. To report SUSPECTED ADVERSE REACTIONS, contact Ajanta Pharma USA Inc., at 855-664-7744 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trial Data Sources Fluvoxamine maleate extended-release capsules were studied in one 12-week controlled trial in patients with OCD (N = 124; mean exposure 66.6 days) and in two 12-week controlled trials for another condition (N = 279; mean exposure 59.2 days). Patients in these trials were initiated on 100 mg/day and were titrated in 50 mg increments over the first 6 weeks to within a range of 100 mg/day to 300 mg/day. The reactions listed in Table 2 show reactions from the two populations separately. Table 3 shows reactions from the three controlled studies combined. 6.2 Adverse Reactions Observed in Controlled Trials Adverse Reactions Associated with Discontinuation of Treatment : Of the 124 patients with OCD and 279 patients in other studies treated with fluvoxamine maleate extended-release capsules in controlled clinical trials, 19% and 26% discontinued treatment due to an adverse reaction. The most common reactions (≥1%) associated with discontinuation and considered to be drug related (i.e., those reactions associated with dropout at a rate at least twice that of placebo) were anorexia (including, but not limited to, loss of appetite and decreased appetite) (1%), anxiety (3%), asthenia (3%), diarrhea (2%), dizziness (4%), headache (2%), insomnia (5%), nausea (7%), nervousness (1%), somnolence (5%), and thinking abnormal (1%). Commonly Observed Adverse Reactions: Fluvoxamine maleate extended-release capsules have been studied in one controlled trial in patients with OCD (N = 124) and two controlled trials for another condition (N = 279). In general, adverse reaction rates were similar in the two data sets as well as in a study of pediatric patients with OCD treated with immediate-release fluvoxamine maleate tablets. The most commonly observed treatment-emergent adverse reactions associated with the use of fluvoxamine maleate extended-release capsules and likely to be drug- related (incidence of 5% or greater and at least twice that for placebo) and derived from Table 2 were: abnormal ejaculation, anorexia, anorgasmia, asthenia, diarrhea, nausea, somnolence, sweating, and tremor . In the one controlled trial in patients with OCD, the following additional reactions occurred at an incidence of 5% or greater and at least twice that for placebo: anxiety, decreased libido, myalgia, pharyngitis, and vomiting . The following additional reactions occurred in another studied population: dyspepsia, dizziness, insomnia, and yawning . In a study evaluating immediate-release fluvoxamine maleate tablets in pediatric patients with OCD, the following additional reactions were identified using the above rule: agitation, depression, dysmenorrhea, flatulence, hyperkinesia, and rash. Adverse Reactions Occurring at an Incidence of ≥ 2%: Table 2 enumerates adverse reactions that occurred in adults at a frequency of 2% or more, and were more frequent than in the placebo group, among patients treated with fluvoxamine maleate extended-release capsules in two short-term, placebo-controlled trials (12 weeks) in another population and one short-term placebo-controlled OCD trial (12 weeks) and in which patients were dosed once-a-day in a range of 100 mg/day to 300 mg/day. This table shows the percentage of patients in each group who had at least one occurrence of a reaction at some time during their treatment. Reported adverse reactions were classified using a 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 may differ from those that 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 health care provider with some basis for estimating the relative contribution of drug and non-drug factors to the side-effect incidence rate in the population

7 DRUG INTERACTIONS Drug Interactions (not described in Contraindications or Warnings and Precautions) include the following: Drugs Inhibiting or Metabolized by Cytochrome P450: Fluvoxamine inhibits several cytochrome P450 isoenzymes (CYP1A2, CYP2C9, CYP3A4, and CYP2C19) ( 7.1 ) . Carbamazepine: Elevated carbamazepine levels and symptoms of toxicity with coadministration ( 7.2 ) . Sumatriptan: Rare postmarketing reports of weakness, hyperreflexia, and incoordination following use of an SSRI and sumatriptan. Monitor appropriately if concomitant treatment is clinically warranted ( 7.2 ) . Tacrine: Coadministration increased tacrine C max and AUC five-and eight-fold and caused nausea, vomiting, sweating, and diarrhea ( 7.2 ) . Tricyclic Antidepressants (TCAs): Coadministration significantly increased plasma TCA levels. Use caution; monitor plasma TCA levels; reduce TCA dose if indicated ( 7.2 ) . Tryptophan: Severe vomiting with coadministration ( 7.2 ) . Diltiazem: Bradycardia with coadministration ( 7.3 ) . Propranolol or Metoprolol: Reduce dose if coadministered with fluvoxamine and titrate more cautiously ( 7.3 ) . 7.1 Potential Interactions with Drugs that Inhibit or are Metabolized by Cytochrome P450 Isoenzymes Multiple hepatic cytochrome P450 isoenzymes are involved in the oxidative biotransformation of a large number of structurally different drugs and endogenous compounds. The available knowledge concerning the relationship of fluvoxamine and the cytochrome P450 isoenzyme system has been obtained mostly from pharmacokinetic interaction studies conducted in healthy volunteers, but some preliminary in vitro data are also available. Based on a finding of substantial interactions of fluvoxamine with certain of these drugs (see later parts of this section and also WARNINGS AND PRECAUTIONS [ 5 ] for details) and limited in vitro data for CYP3A4, it appears that fluvoxamine inhibits several cytochrome P450 isoenzymes that are known to be involved in the metabolism of other drugs such as: CYP1A2 (e.g., warfarin, theophylline, propranolol, tizanidine), CYP2C9 (e.g., warfarin), CYP3A4 (e.g., alprazolam), and CYP2C19 (e.g., omeprazole). In vitro data suggest that fluvoxamine is a relatively weak inhibitor of CYP2D6. Approximately 7% of the normal population has a genetic code that leads to reduced levels of activity of CYP2D6 enzyme. Such individuals have been referred to as “poor metabolizers” (PM) of drugs such as debrisoquin, dextromethorphan, and tricyclic antidepressants. While none of the drugs studied for drug interactions significantly affected the pharmacokinetics of fluvoxamine, an in vivo study of fluvoxamine single-dose pharmacokinetics in 13 PM subjects demonstrated altered pharmacokinetic properties compared to 16 “extensive metabolizers” (EM): mean C max , AUC, and half-life were increased by 52%, 200%, and 62%, respectively, in the PM compared to the EM group. This suggests that fluvoxamine is metabolized, at least in part, by CYP2D6. Caution is indicated in patientsknown to have reduced levels of cytochrome P450 2D6 activity and those receiving concomitant drugs known to inhibit this cytochrome P450 isoenzyme (e.g., quinidine). The metabolism of fluvoxamine has not been fully characterized and the effects of potent cytochrome P450 isoenzyme inhibition, such as the ketoconazole inhibition of CYP3A4, on fluvoxamine metabolism have not been studied. A clinically significant fluvoxamine interaction is possible with drugs having a narrow therapeutic ratio such as pimozide, warfarin, theophylline, certain benzodiazepines, omeprazole, and phenytoin. If fluvoxamine maleate extended-release capsules are to be administered together with a drug that is eliminated via oxidative metabolism and has a narrow therapeutic window, plasma levels and/or pharmacodynamic effects of the latter drug should be monitored closely, at least until steady-state conditions are reached (see CONTRAINDICATIONS [ 4 ] and WARNINGS AND PRECAUTIONS [ 5 ] ). 7.2 CNS Active Drugs Antipsychotics: See WARNINGS AND PRECAUTIONS ( 5.2 ) . Benzodiazepines: See WARNINGS AND PRECAUTIONS ( 5.9 ) . Alprazolam: See WARNINGS AND PRECAUTIONS ( 5.9 ) . Diazepam: See WARNINGS AND PRECAUTIONS ( 5.9 ). Lorazepam : A study of multiple doses of immediate-release fluvoxamine maleate tablets (50 mg given twice daily) in healthy male volunteers (N=12) and a single dose of lorazepam (4 mg single dose) indicated no significant pharmacokinetic interaction. On average, both lorazepam alone and lorazepam with fluvoxamine produced substantial decrements in cognitive functioning; however, the coadministration of fluvoxamine and lorazepam did not produce larger mean decrements compared to lorazepam alone. Alcohol: Studies involving single 40 g doses of ethanol (oral administration in one study and intravenous in the other) and multiple dosing with immediate-release fluvoxamine maleate tablets (50 mg given twice daily) revealed no effect of either drug on the pharm