fluvoxamine

Absorption: 53% absorbed after oral administration.

Distribution: Enters the CNS. Remainder of distribution not known.

Metabolism/Excretion: Mostly metabolized by the liver via the CYP2D6 isoenzyme; the CYP2D6 isoenzyme exhibits genetic polymorphism; ∼7% of population may be poor metabolizers and may have significantly ↑ fluvoxamine concentrations and an ↑ risk of adverse effects.

Half-Life: 13.6–15.6 hr.

Time/Action Profile ⬆ ⬇

(improvement on obsessive-compulsive behaviors)

ROUTE	ONSET	PEAK	DURATION
PO	within 2–3 wk	several mo	unknown

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity to fluvoxamine or other SSRIs;
Concurrent use of MAO inhibitors (or within 14 days of discontinuing fluvoxamine), MAO inhibitor-like drugs (linezolid or methylene blue), alosetron, pimozide, thioridazine, or tizanidine.

Use Cautiously in:

Hepatic impairment;
Risk of suicide (may ↑ risk of suicide attempt/ideation especially during early treatment or dose adjustment);
Angle-closure glaucoma;
OB: Neonates exposed to SSRI in third trimester may develop drug discontinuation syndrome including respiratory distress, feeding difficulty, and irritability;
Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
Pedi: Risk of suicidal ideation or attempt may be greater in children or adolescents;
Pedi: Safety and effectiveness not established in children 18 yr (controlled release) and 8 yr (immediate-release);
Geri: Appears on Beers list. May worsen or cause syndrome of inappropriate antidiuretic hormone (SIADH) secretion and/or hyponatremia in older adults. Use with caution in older adults and closely monitor sodium concentrations when starting therapy or dose.

Adv. Reactions/Side Effects ⬆ ⬇

CV: edema, hypertension, palpitations, postural hypotension, tachycardia

Derm: ↑sweating

EENT: sinusitis

Endo: SIADH

F and E: hyponatremia

GI: constipation, diarrhea, dry mouth, dyspepsia, nausea, ↑liver enzymes, anorexia, dysphagia, flatulence, vomiting, weight loss

GU: ↓libido, delayed/absent orgasm, ejaculatory delay/failure, erectile dysfunction

Hemat: BLEEDING

Metab: weight gain

MS: hypertonia, myoclonus/twitching

Neuro: dizziness, drowsiness, headache, insomnia, nervousness, weakness, agitation, anxiety, apathy, depression, emotional lability, hypokinesia/hyperkinesia, manic reactions, NEUROLEPTIC MALIGNANT SYNDROME, psychotic reactions, sedation, SUICIDAL THOUGHTS, syncope, tremor

Resp: cough, dyspnea

Misc: chills, flu-like symptoms, hypersensitivity reactions, SEROTONIN SYNDROME, tooth disorder/caries, yawning

Interactions ⬆ ⬇

Drug-drug:

Concurrent use with MAO inhibitors may result in serious potentially fatal reactions (MAO inhibitors should be stopped at least 14 days before fluvoxamine therapy. Fluvoxamine should be stopped at least 14 days before MAO inhibitor therapy).
Concurrent use with MAO-inhibitor-like drugs, such as linezolid or methylene blue may ↑ risk of serotonin syndrome; concurrent use contraindicated; do not start therapy in patients receiving linezolid or methylene blue; if linezolid or methylene blue need to be started in a patient receiving fluvoxamine, immediately discontinue fluvoxamine and monitor for signs/symptoms of serotonin syndrome for 2 wk or until 24 hr after last dose of linezolid or methylene blue, whichever comes first (may resume fluvoxamine therapy 24 hr after last dose of linezolid or methylene blue)
Smoking may ↓ effectiveness of fluvoxamine.
Concurrent use with tricyclic antidepressants may ↑ plasma levels of fluvoxamine.
Drugs that affect serotonergic neurotransmitter systems, including tricyclic antidepressants, SNRIs, fentanyl, lithium, buspirone, tramadol, meperidine, methadone, amphetamines, and triptans↑ risk of serotonin syndrome
↓metabolism and may ↑ effects of some beta blockers (propranolol), alosetron (avoid concurrent use), some benzodiazepines (avoid concurrent diazepam), carbamazepine, methadone, lithium, theophylline (↓ dose to 33% of usual dose), ramelteon (avoid concurrent use), warfarin, and l-tryptophan.
↑risk of bleeding with NSAIDs, aspirin, clopidogrel, prasugrel, ticagrelor, dabigatran, apixaban, edoxaban, rivaroxaban, or warfarin.
↑blood levels and risk of toxicity from clozapine (dose adjustments may be necessary).

Drug-Natural Products:

Use with St. John's wort↑ of serotonin syndrome.

Route/Dosage ⬆ ⬇

PO (Adults ): Immediate release: 50 mg daily at bedtime; ↑ by 50 mg every 4–7 days until desired effect is achieved. If daily dose >100 mg, give in 2 equally divided doses or give a larger dose at bedtime (not to exceed 300 mg/day); Controlled release: 100 mg at bedtime; ↑ by 50 mg every 7 days until desired effect is achieved, not to exceed 300 mg/day.
PO (Children 8–17 yr): Immediate release: 25 mg at bedtime, may ↑ by 25 mg/day every 4–7 days (not to exceed 200 mg/day; daily doses >50 mg should be given in divided doses with a larger dose at bedtime).

Hepatic Impairment

PO (Adults ): Immediate release: 25 mg daily at bedtime initially, slower titration, and longer dosing intervals should be used.

Availability ⬆ ⬇

(Generic available)

Tablets: 25 mg; 50 mg; 100 mg
Controlled-release capsules: 100 mg; 150 mg

Assessment ⬆ ⬇

Monitor mood changes. Assess patient for frequency of obsessive-compulsive behaviors. Note degree to which these thoughts and behaviors interfere with daily functioning. Inform health care professional if patient demonstrates significant increase in anxiety, nervousness, or insomnia.
Assess for suicidal tendencies, especially during early therapy. Restrict amount of drug available to patient. Risk may be increased in children, adolescents, and adults ≤24 yr. After starting therapy, children, adolescents, and young adults should be seen by health care professional at least weekly for 4 wk, every 3 wk for next 4 wk, and on advice of health care professional thereafter.
Monitor appetite and nutritional intake. Weigh weekly. Report significant changes in weight. Adjust diet as tolerated to support nutritional status.
Assess sexual function before starting fluvoxamine. Assess for changes in sexual function during treatment, including timing of onset; patient may not report.
Assess for serotonin syndrome (mental changes [agitation, hallucinations, coma], autonomic instability [tachycardia, labile BP, hyperthermia], neuromuscular aberrations [hyperreflexia, incoordination], and/or GI symptoms [nausea, vomiting, diarrhea]), especially in patients taking other serotonergic drugs (SSRIs, SNRIs, triptans).

Toxicity and Overdose:

Common symptoms of toxicity include drowsiness, vomiting, diarrhea, and dizziness. Coma, tachycardia, bradycardia, hypotension, ECG abnormalities, liver function abnormalities, and convulsions may also occur. Treatment is symptomatic and supportive.

Implementation ⬆ ⬇

Do not confuse fluvoxamine with fluphenazine or flavoxate.
Taper to avoid withdrawal effects. Reduce dose by 50% for 3 days, then reduce by 50% for 3 days, then discontinue.
PO: Initial therapy is administered as a single bedtime dose. May be increased every 4–7 days as tolerated.
- Fluvoxamine may be given without regard to meals. DNC: Do not open, break, crush, or chew controlled-release capsules.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take fluvoxamine as directed. Do not skip or double up on missed doses. Improvement in symptoms may be noticed in 2–3 wk, but medication should be continued as directed.
May cause drowsiness and dizziness. Caution patient to avoid driving and other activities requiring alertness until response to medication is known.
Advise patient, family, and caregivers to look for suicidality, especially during early therapy or dose changes. Notify health care professional immediately if thoughts about suicide or dying, attempts to commit suicide, new or worse depression or anxiety, agitation or restlessness, panic attacks, insomnia, new or worse irritability, aggressiveness, acting on dangerous impulses, mania, or other changes in mood or behavior or if symptoms of serotonin syndrome occur.
Advise patient to notify health care professional if rash or hives occur or if headache, nausea, anorexia, anxiety, or insomnia persists.
Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications, especially St. John's wort. Advise patient to avoid taking other CNS depressants, including opioids, or alcohol.
Advise patient to avoid use of caffeine (chocolate, tea, cola).
Inform patient that fluvoxamine may cause symptoms of sexual dysfunction. In males, ejaculatory delay or failure, decreased libido, and erectile dysfunction may occur. In female patients, may result in decreased libido and delayed or absent orgasm. Advise patient to notify health care professional if symptoms occur.
Rep: May cause fetal harm. Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected, or if breastfeeding. Monitor infants exposed to fluvoxamine during 3rd trimester for respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia, hyperreflexia, tremors, jitteriness, irritability, and constant crying. May increase risk of postpartum hemorrhage. Monitor infants exposed to fluvoxamine via breast milk for agitation, irritability, poor feeding, and poor weight gain. Inform patient of pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antidepressants during pregnancy. Register patient by calling the National Pregnancy Registry for Antidepressants at 1-866-961-2388 or visiting online at https://womensmentalhealth.org/clinical-and-researchprograms/pregnancyregistry/antidepressants/.
Emphasize the importance of follow-up exams to monitor progress.

section name header

Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇