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 fluvoxamine maleate is not approved for use in treating bipolar depression.
Benzodiazepines: Benzodiazepines metabolized by hepatic oxidation (e.g., alprazolam, midazolam, triazolam, etc.) should be used with caution because the clearance of these drugs is likely to be reduced by fluvoxamine. The clearance of benzodiazepines metabolized by glucuronidation (e.g., lorazepam, oxazepam, temazepam) is unlikely to be affected by fluvoxamine.
Alprazolam: When fluvoxamine maleate (100 mg q.i.d.) and alprazolam (1 mg q.i.d.) were coadministered to steady state, plasma concentrations and other pharmacokinetic parameters (AUC, Cmax, T½) of alprazolam were approximately twice those observed when alprazolam was administered alone; oral clearance was reduced by about 50%. The elevated plasma alprazolam concentrations resulted in decreased psychomotor performance and memory. This interaction, which has not been investigated using higher doses of fluvoxamine, may be more pronounced if a 300 mg daily dose is coadministered, particularly since fluvoxamine exhibits non-linear pharmacokinetics over the dosage range 100 mg to 300 mg. If alprazolam is coadministered with fluvoxamine maleate, the initial alprazolam dosage should be at least halved and titration to the lowest effective dose is recommended. No dosage adjustment is required for fluvoxamine maleate.
Diazepam: The coadministration of fluvoxamine maleate and diazepam is generally not advisable. Because fluvoxamine reduces the clearance of both diazepam and its active metabolite, N-desmethyldiazepam, there is a strong likelihood of substantial accumulation of both species during chronic coadministration.
Evidence supporting the conclusion that it is inadvisable to coadminister fluvoxamine and diazepam is derived from a study in which healthy volunteers taking 150 mg/day of fluvoxamine were administered a single oral dose of 10 mg of diazepam. In these subjects (N=8), the clearance of diazepam was reduced by 65% and that of N-desmethyldiazepam to a level that was too low to measure over the course of the 2-week long study.
It is likely that this experience significantly underestimates the degree of accumulation that might occur with repeated diazepam administration. Moreover, as noted with alprazolam, the effect of fluvoxamine may even be more pronounced when it is administered at higher doses. Accordingly, diazepam and fluvoxamine should not ordinarily be coadministered.
Clozapine: Elevated serum levels of clozapine have been reported in patients taking fluvoxamine maleate and clozapine. Since clozapine-related seizures and orthostatic hypotension appear to be dose related, the risk of these adverse events may be higher when fluvoxamine and clozapine are coadministered. Patients should be closely monitored when fluvoxamine maleate and clozapine are used concurrently.
Methadone: Significantly increased methadone (plasma level: dose) ratios have been reported when fluvoxamine maleate was administered to patients receiving maintenance methadone treatment, with symptoms of opioid intoxication in one patient. Opioid withdrawal symptoms were reported following fluvoxamine maleate discontinuation in another patient.
Mexiletine: The effect of steady-state fluvoxamine (50 mg b.i.d. for 7 days) on the single dose pharmacokinetics of mexiletine (200 mg) was evaluated in 6 healthy Japanese males. The clearance of mexiletine was reduced by 38% following coadministration with fluvoxamine compared to mexiletine alone. If fluvoxamine and mexiletine are coadministered, serum mexiletine levels should be monitored.
Ramelteon: When fluvoxamine 100 mg twice daily was administered for 3 days prior to single-dose coadministration of ramelteon 16 mg and fluvoxamine, the AUC for ramelteon increased approximately 190-fold and the Cmax increased approximately 70-fold compared to ramelteon administered alone. Ramelteon should not be used in combination with fluvoxamine.
Theophylline: The effect of steady-state fluvoxamine (50 mg b.i.d.) on the pharmacokinetics of a single dose of theophylline (375 mg as 442 mg aminophylline) was evaluated in 12 healthy non-smoking, male volunteers. The clearance of theophylline was decreased approximately 3-fold. Therefore, if theophylline is coadministered with fluvoxamine maleate, its dose should be reduced to one-third of the usual daily maintenance dose and plasma concentrations of theophylline should be monitored. No dosage adjustment is required for fluvoxamine maleate.
Warfarin and Other Drugs That Interfere with Hemostasis (NSAIDs, Aspirin, etc.): Serotonin release by platelets plays an important role in hemostasis. Epidemiological studies of the case-control and cohort design have demonstrated an association between 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 an NSAID or aspirin may potentiate this risk of bleeding. Thus, patients should be cautioned about the use of such drugs concurrently with fluvoxamine [see Warnings and Precautions (5.10)].
Warfarin: When fluvoxamine maleate (50 mg t.i.d.) was administered concomitantly with warfarin for two weeks, warfarin plasma concentrations increased by 98% and prothrombin times were prolonged. Thus patients receiving oral anticoagulants and fluvoxamine maleate should have their prothrombin time monitored and their anticoagulant dose adjusted accordingly. No dosage adjustment is required for fluvoxamine maleate.
Patients with Hepatic Impairment: In patients with liver dysfunction, fluvoxamine clearance was decreased by approximately 30%. Patients with liver dysfunction should begin with a low dose of fluvoxamine maleate and increase it slowly with careful monitoring.
Commonly Observed Adverse Reactions in Controlled Clinical Trials: Fluvoxamine maleate has been studied in 10-week short-term controlled trials of OCD (N=320) and depression (N=1,350). In general, adverse reaction rates were similar in the two data sets as well as in the pediatric OCD study. The most commonly observed adverse reactions associated with the use of fluvoxamine maleate and likely to be drug-related (incidence of 5% or greater and at least twice that for placebo) derived from Table 2 were: nausea, somnolence, insomnia, asthenia, nervousness, dyspepsia, abnormal ejaculation, sweating, anorexia, tremor, and vomiting. In a pool of two studies involving only patients with OCD, the following additional reactions were identified using the above rule: anorgasmia, decreased libido, dry mouth, rhinitis, taste perversion, and urinary frequency. In a study of 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 1%: Table 2 enumerates adverse reactions that occurred in adults at a frequency of 1% or more, and were more frequent than in the placebo group, among patients treated with fluvoxamine maleate in two short-term placebo controlled OCD trials (10 week) and depression trials (6 week) in which patients were dosed in a range of generally 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 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 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 physician with some basis for estimating the relative contribution of drug and non-drug factors to the side-effect incidence rate in the population studied.
Table 2: Treatment-Emergent Adverse Reaction Incidence Rates by Body System in Adult OCD and Depression Populations CombinedReactions for which fluvoxamine maleate incidence was equal to or less than placebo are not listed in the table above.
Body System/ Adverse Reaction | Percentage of Patients Reporting Reaction |
|---|
Fluvoxamine Maleate N=892 | Placebo N=778 |
|---|
| Body as a Whole |
| Headache | 22 | 20 |
| Asthenia | 14 | 6 |
| Flu Syndrome | 3 | 2 |
| Chills | 2 | 1 |
| Cardiovascular |
| Palpitations | 3 | 2 |
| Digestive System |
| Nausea | 40 | 14 |
| Diarrhea | 11 | 7 |
| Constipation | 10 | 8 |
| Dyspepsia | 10 | 5 |
| Anorexia | 6 | 2 |
| Vomiting | 5 | 2 |
| Flatulence | 4 | 3 |
| Tooth Disorder Includes "toothache," "tooth extraction and abscess," and "caries." | 3 | 1 |
| Dysphagia | 2 | 1 |
| Nervous System |
| Somnolence | 22 | 8 |
| Insomnia | 21 | 10 |
| Dry Mouth | 14 | 10 |
| Nervousness | 12 | 5 |
| Dizziness | 1 | 6 |
| Tremor | 5 | 1 |
| Anxiety | 5 | 3 |
| Vasodilatation Mostly feeling warm, hot, or flushed. | 3 | 1 |
| Hypertonia | 2 | 1 |
| Agitation | 2 | 1 |
| Decreased Libido | 2 | 1 |
| Depression | 2 | 1 |
| CNS Stimulation | 2 | 1 |
| Respiratory System |
| Upper Respiratory Infection | 9 | 5 |
| Dyspnea | 2 | 1 |
| Yawn | 2 | 0 |
| Skin |
| Sweating | 7 | 3 |
| Special Senses |
| Taste Perversion | 3 | 1 |
| Amblyopia Mostly "blurred vision." | 3 | 2 |
| Urogenital |
| Abnormal Ejaculation Mostly "delayed ejaculation." ,Incidence based on number of male patients. | 8 | 1 |
| Urinary Frequency | 3 | 2 |
| Impotence | 2 | 1 |
| Anorgasmia | 2 | 0 |
| Urinary Retention | 1 | 0 |
Adverse Reactions in OCD Placebo Controlled Studies Which are Markedly Different (defined as at least a two-fold difference) in Rate from the Pooled Reaction Rates in OCD and Depression Placebo Controlled Studies: The reactions in OCD studies with a two-fold decrease in rate compared to reaction rates in OCD and depression studies were dysphagia and amblyopia (mostly blurred vision). Additionally, there was an approximate 25% decrease in nausea.
The reactions in OCD studies with a two-fold increase in rate compared to reaction rates in OCD and depression studies were: asthenia, abnormal ejaculation (mostly delayed ejaculation), anxiety, rhinitis, anorgasmia (in males), depression, libido decreased, pharyngitis, agitation, impotence, myoclonus/twitch, thirst, weight loss, leg cramps, myalgia, and urinary retention. These reactions are listed in order of decreasing rates in the OCD trials.
Antipsychotics: See Warnings and Precautions (5.2).
Benzodiazepines: See Warnings and Precautions (5.8).
Alprazolam: See Warnings and Precautions (5.8).
Diazepam: See Warnings and Precautions (5.8).
Lorazepam: A study of multiple doses of fluvoxamine maleate (50 mg b.i.d.) 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 fluvoxamine maleate (50 mg b.i.d.) revealed no effect of either drug on the pharmacokinetics or pharmacodynamics of the other. As with other psychotropic medications, patients should be advised to avoid alcohol while taking fluvoxamine maleate.
Carbamazepine: Elevated carbamazepine levels and symptoms of toxicity have been reported with the coadministration of fluvoxamine maleate and carbamazepine.
Clozapine: See Warnings and Precautions (5.8).
Lithium: As with other serotonergic drugs, lithium may enhance the serotonergic effects of fluvoxamine and, therefore, the combination should be used with caution. Seizures have been reported with the coadministration of fluvoxamine maleate and lithium.
Methadone: See Warnings and Precautions (5.8).
Monoamine Oxidase Inhibitors: See Dosage and Administration (2.5, 2.6), Contraindications (4.2) and Warnings and Precautions (5.2).
Pimozide: See Contraindications (4.1) and Warnings and Precautions (5.6).
Ramelteon: See Warnings and Precautions (5.8).
Serotonergic Drugs: See Dosage and Administration (2.5, 2.6), Contraindications (4.2) and Warnings and Precautions (5.2).
Tacrine: In a study of 13 healthy, male volunteers, a single 40 mg dose of tacrine added to fluvoxamine 100 mg/day administered at steady-state was associated with five- and eight-fold increases in tacrine Cmax and AUC, respectively, compared to the administration of tacrine alone. Five subjects experienced nausea, vomiting, sweating, and diarrhea following coadministration, consistent with the cholinergic effects of tacrine.
Thioridazine: See Contraindications (4.1) and Warnings and Precautions (5.4).
Tizanidine: See Contraindications (4.1) and Warnings and Precautions (5.5).
Tricyclic Antidepressants (TCAs): Significantly increased plasma TCA levels have been reported with the coadministration of fluvoxamine maleate and amitriptyline, clomipramine or imipramine. Caution is indicated with the coadministration of fluvoxamine maleate and TCAs; plasma TCA concentrations may need to be monitored, and the dose of TCA may need to be reduced.
Triptans: There have been rare post-marketing reports of serotonin syndrome with use of an SSRI and a triptan. If concomitant treatment of fluvoxamine with a triptan is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases [see Warnings and Precautions (5.2)].
Sumatriptan: There have been rare post-marketing reports describing patients with weakness, hyperreflexia, and incoordination following the use of a selective serotonin reuptake inhibitor (SSRI) and sumatriptan. If concomitant treatment with sumatriptan and an SSRI (e.g., fluoxetine, fluvoxamine, paroxetine, sertraline) is clinically warranted, appropriate observation of the patient is advised.
Tryptophan: Tryptophan may enhance the serotonergic effects of fluvoxamine, and the combination should, therefore, be used with caution. Severe vomiting has been reported with the coadministration of fluvoxamine maleate and tryptophan [see Warnings and Precautions (5.2)].
Alosetron: See Contraindications (4.1), Warnings and Precautions (5.7), and Lotronex® (alosetron) package insert.
Digoxin: Administration of fluvoxamine maleate 100 mg daily for 18 days (N=8) did not significantly affect the pharmacokinetics of a 1.25 mg single intravenous dose of digoxin.
Diltiazem: Bradycardia has been reported with the coadministration of fluvoxamine maleate and diltiazem.
Mexiletine: See Warnings and Precautions (5.8).
Propranolol and Other Beta-Blockers: Coadministration of fluvoxamine maleate 100 mg per day and propranolol 160 mg per day in normal volunteers resulted in a mean five-fold increase (range 2 to 17) in minimum propranolol plasma concentrations. In this study, there was a slight potentiation of the propranolol-induced reduction in heart rate and reduction in the exercise diastolic pressure. One case of bradycardia and hypotension and a second case of orthostatic hypotension have been reported with the coadministration of fluvoxamine maleate and metoprolol.
If propranolol or metoprolol is coadministered with fluvoxamine maleate, a reduction in the initial beta-blocker dose and more cautious dose titration are recommended. No dosage adjustment is required for fluvoxamine maleate.
Coadministration of fluvoxamine maleate 100 mg per day with atenolol 100 mg per day (N=6) did not affect the plasma concentrations of atenolol. Unlike propranolol and metoprolol which undergo hepatic metabolism, atenolol is eliminated primarily by renal excretion.
Theophylline: See Warnings and Precautions (5.8).
Warfarin and Other Drugs That Interfere with Hemostasis (NSAIDs, Aspirin, etc.): See Warnings and Precautions (5.8, 5.10).
Absorption: The absolute bioavailability of fluvoxamine maleate is 53%. Oral bioavailability is not significantly affected by food.
In a dose proportionality study involving fluvoxamine maleate at 100 mg/day, 200 mg/day and 300 mg/day for 10 consecutive days in 30 normal volunteers, steady state was achieved after about a week of dosing. Maximum plasma concentrations at steady state occurred within 3 to 8 hours of dosing and reached concentrations averaging 88 ng/mL, 283 ng/mL and 546 ng/mL, respectively. Thus, fluvoxamine had nonlinear pharmacokinetics over this dose range, i.e., higher doses of fluvoxamine maleate produced disproportionately higher concentrations than predicted from the lower dose.
Distribution: The mean apparent volume of distribution for fluvoxamine is approximately 25 L/kg, suggesting extensive tissue distribution.
Approximately 80% of fluvoxamine is bound to plasma protein, mostly albumin, over a concentration range of 20 ng/mL to 2000 ng/mL.
Metabolism: Fluvoxamine maleate is extensively metabolized by the liver; the main metabolic routes are oxidative demethylation and deamination. Nine metabolites were identified following a 5 mg radiolabelled dose of fluvoxamine maleate, constituting approximately 85% of the urinary excretion products of fluvoxamine. The main human metabolite was fluvoxamine acid which, together with its N-acetylated analog, accounted for about 60% of the urinary excretion products. A third metabolite, fluvoxethanol, formed by oxidative deamination, accounted for about 10%. Fluvoxamine acid and fluvoxethanol were tested in an in vitro assay of serotonin and norepinephrine reuptake inhibition in rats; they were inactive except for a weak effect of the former metabolite on inhibition of serotonin uptake (1 to 2 orders of magnitude less potent than the parent compound). Approximately 2% of fluvoxamine was excreted in urine unchanged [see Drug Interactions (7)].
Elimination: Following a 14C-labelled oral dose of fluvoxamine maleate (5 mg), an average of 94% of drug-related products was recovered in the urine within 71 hours.
The mean plasma half-life of fluvoxamine at steady state after multiple oral doses of 100 mg/day in healthy, young volunteers was 15.6 hours.
Elderly Subjects: In a study of fluvoxamine maleate at 50 mg and 100 mg comparing elderly (ages 66 to 73) and young subjects (ages 19 to 35), mean maximum plasma concentrations in the elderly were 40% higher. The multiple dose elimination half-life of fluvoxamine was 17.4 and 25.9 hours in the elderly compared to 13.6 and 15.6 hours in the young subjects at steady state for 50 mg and 100 mg doses, respectively. In elderly patients, the clearance of fluvoxamine was reduced by about 50% and, therefore, fluvoxamine maleate should be slowly titrated during initiation of therapy [see Dosage and Administration (2.3)].
Pediatric Subjects: The multiple-dose pharmacokinetics of fluvoxamine was determined in male and female children (ages 6 to 11) and adolescents (ages 12 to 17). Steady-state plasma fluvoxamine concentrations were 2- to 3-fold higher in children than in adolescents. AUC and Cmax in children were 1.5- to 2.7-fold higher than that in adolescents [see Table 4]. As in adults, both children and adolescents exhibited nonlinear multiple-dose pharmacokinetics. Female children showed significantly higher AUC0–12 and Cmax compared to male children and, therefore, lower doses of fluvoxamine maleate may produce therapeutic benefit [see Table 5]. No gender differences were observed in adolescents. Steady-state plasma fluvoxamine concentrations were similar in adults and adolescents at a dose of 300 mg/day, indicating that fluvoxamine exposure was similar in these two populations [see Table 4]. Dose adjustment in adolescents (up to the adult maximum dose of 300 mg) may be indicated to achieve therapeutic benefit [see Dosage and Administration (2.2)].
Table 4: Comparison of Mean (SD) Fluvoxamine Pharmacokinetic Parameters Between Children, Adolescents and AdultsPharmacokinetic Parameter (body weight corrected) | Dose = 200 mg/day (100 mg b.i.d.) | Dose = 300 mg/day (150 mg b.i.d.) |
|---|
Children (N=10) | Adolescent (N=17) | Adolescent (N=13) | Adult (N=16) |
|---|
| AUC0–12 (ng∙h/mL/kg) | 155.1 (160.9) | 43.9 (27.9) | 69.6 (46.6) | 59.4 (40.9) |
| Cmax (ng/mL/kg) | 14.8 (14.9) | 4.2 (2.6) | 6.7 (4.2) | 5.7 (3.9) |
| Cmin (ng/mL/kg) | 11.0 (11.9) | 2.9 (2.0) | 4.8 (3.8) | 4.6 (3.2) |
Table 5: Comparison of Mean (SD) Fluvoxamine Pharmacokinetic Parameters Between Male and Female Children (6 to 11 Years)Pharmacokinetic Parameter (body weight corrected) | Dose = 200 mg/day (100 mg b.i.d.) |
|---|
| Male Children (N=7) | Female Children (N=3) |
|---|
| AUC0–12 (ng∙h/mL/kg) | 95.8 (83.9) | 293.5 (233.0) |
| Cmax (ng/mL/kg) | 9.1 (7.6) | 28.1 (21.1) |
| Cmin (ng/mL/kg) | 6.6 (6.1) | 21.2 (17.6) |
Hepatic and Renal Disease: A cross study comparison (healthy subjects versus patients with hepatic dysfunction) suggested a 30% decrease in fluvoxamine clearance in association with hepatic dysfunction. The mean minimum plasma concentrations in renally impaired patients (creatinine clearance of 5 mL/min to 45 mL/min) after 4 and 6 weeks of treatment (50 mg b.i.d., N=13) were comparable to each other, suggesting no accumulation of fluvoxamine in these patients [see Warnings and Precautions (5.14)].
Carcinogenesis: There was no evidence of carcinogenicity in rats treated orally with fluvoxamine maleate for 30 months or hamsters treated orally with fluvoxamine maleate for 20 (females) or 26 (males) months. The daily doses in the high dose groups in these studies were increased over the course of the study from a minimum of 160 mg/kg to a maximum of 240 mg/kg in rats, and from a minimum of 135 mg/kg to a maximum of 240 mg/kg in hamsters. The maximum dose of 240 mg/kg is approximately 6 times the maximum human daily dose on a mg/m2 basis.
Mutagenesis: No evidence of genotoxic potential was observed in a mouse micronucleus test, an in-vitro chromosome aberration test, or the Ames microbial mutagen test with or without metabolic activation.
Impairment of Fertility: In a study in which male and female rats were administered fluvoxamine (60 mg/kg, 120 mg/kg, or 240 mg/kg) prior to and during mating and gestation, fertility was impaired at oral doses of 120 mg/kg or greater, as evidenced by increased latency to mating, decreased sperm count, decreased epididymal weight, and decreased pregnancy rate. In addition, the numbers of implantations and embryos were decreased at the highest dose. The no effect dose for fertility impairment was 60 mg/kg (approximately 2 times the maximum recommended human dose [MRHD] on a mg/m2 basis).
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