fluvoxamine

Fluvoxamine is an antidepressant in the selective serotonin reuptake inhibitor (SSRI) class. It is approved for obsessive-compulsive disorder (OCD) and is marketed as Luvox, with Luvox CR as an extended-release option in some regions. It is also used for social anxiety disorder in certain countries and is sometimes prescribed off label for other anxiety disorders and depression.

Mechanism and pharmacology: Fluvoxamine increases serotonin in synapses by inhibiting the serotonin transporter. It is extensively metabolized in the liver and strongly inhibits several cytochrome P450 enzymes, especially CYP1A2 and CYP2C19, with lesser effects on CYP3A4. These properties can raise levels of concomitant medications such as clozapine, theophylline, and certain anticoagulants or antiplatelets.

Dosing: For OCD, start at 25 mg at night for 1–2 weeks, then increase by 25–50 mg per week. Typical maintenance ranges are 100–300 mg per day; maximum daily dose is commonly 300 mg. Luvox CR is given as 100–300 mg once daily, adjusted by response and tolerability.

Adverse effects and precautions: Common adverse effects include somnolence, nausea, insomnia, dry mouth, sweating, and sexual dysfunction. Serotonin syndrome, hyponatremia, and mania are potential risks, particularly with other serotonergic drugs or in bipolar disorder. Caution in liver impairment and elderly patients; avoid concomitant use with monoamine oxidase inhibitors and monitor for bleeding with NSAIDs.