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;
May ↑ risk of suicide attempt/ideation especially during early treatment or dose adjustment; this risk appears to be greater in adolescents or children
;
Angle-closure glaucoma;
OB: Neonates exposed to SSRI in 3rd 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: May ↑ risk of suicide attempt/ideation especially during early treatment or dose adjustment; 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/BEHAVIORS, 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).
May ↑ thioridazine and pimozide levels and risk of QT interval prolongation and torsades de pointes; concurrent use contraindicated.
May ↑ levels and risk of toxicity of tizanidine and alosetron; concurrent use contraindicated.
Smoking may ↓ levels and effectiveness.
Tricyclicantidepressants may ↑ levels and risk of toxicity.
Drugs that affect serotonergic neurotransmitter systems, including tricyclic antidepressants, SNRIs, fentanyl, lithium, buspirone, tramadol, meperidine, methadone, amphetamines, and triptans, may ↑ risk of serotonin syndrome.
May ↑ levels and risk of toxicity of some beta blockers (propranolol), some benzodiazepines (avoid concurrent diazepam), carbamazepine, methadone, lithium, theophylline (↓ dose to 33% of usual dose), ramelteon (avoid concurrent use), warfarin, and l-tryptophan.
May ↑ risk of bleeding with NSAIDs, aspirin, clopidogrel, prasugrel, ticagrelor, dabigatran, apixaban, edoxaban, rivaroxaban, or warfarin.
May ↑ levels and risk of toxicity of clozapine; dose adjustments may be necessary.

Drug-Natural Products:

St. John's wort may ↑ risk of of serotonin syndrome.

Route/Dosage ⬆ ⬇

PO (Adults ): Immediate release: 50 mg once 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 once daily 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 once daily 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 once 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 frequency of obsessive-compulsive behaviors. Note degree to which these thoughts and behaviors interfere with daily functioning. Inform health care provider if patient demonstrates significant ↑ in anxiety, nervousness, or insomnia.
Assess for suicidal tendencies, especially during early therapy. Restrict amount of drug available to patient. Risk may be ↑ in children, adolescents, and adults ≤24 yr. After starting therapy, children, adolescents, and young adults should be seen by health care provider at least weekly for 4 wk, every 3 wk for next 4 wk, and on advice of health care provider thereafter.
Monitor appetite and nutritional intake. Weigh weekly. Report significant changes in weight. Adjust diet as tolerated to support nutritional status.
Assess for bleeding (hemoptysis; coffee grounds vomit; hematuria; black, red, or tarry stools; bleeding from the gums; abnormal vaginal bleeding; bruises without a cause).
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], GI symptoms [nausea, vomiting, diarrhea]), especially in patients taking other serotonergic drugs (SSRIs, SNRIs, triptans).

Lab Test Considerations:

Monitor liver and renal function tests.

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. ↓ dose by 50% for 3 days; then ↓ by 50% for 3 days; then discontinue.
PO: Initial therapy is administered as a single bedtime dose. May be ↑ every 4–7 days as tolerated.
- Administer without regard to meals. DNC: Swallow capsules whole. Do not open, break, crush, or chew controlled-release capsules.

Patient/Family Teaching ⬆ ⬇

Explain purpose and side effects of medication to patient. Advise patient to read Patient Information before starting therapy. Instruct patient to take 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.
Instruct patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care provider before taking any new medications, especially St. John's wort. Advise patient to avoid taking other CNS depressants, including opioids, or alcohol.
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 provider 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 occur or if symptoms of serotonin syndrome occur.
Advise patient to report any signs of uncontrolled bleeding.
Advise patient to notify health care provider if rash or hives occur or if headache, nausea, anorexia, anxiety, or insomnia persists.
Advise patient to avoid use of caffeine (chocolate, tea, cola).
Inform patient that fluvoxamine may cause symptoms of sexual dysfunction. In men, ejaculatory delay or failure, ↓ libido, and erectile dysfunction may occur. In women, may result in ↓ libido and delayed or absent orgasm. Advise patient to notify health care provider if symptoms occur.
Rep: May cause fetal harm. Advise women of reproductive potential to notify health care provider 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 ↑ 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/.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇