Fluvoxamine

Key facts

• Fluvoxamine is a selective serotonin reuptake inhibitor (SSRI). It increases the amount of serotonin available between nerve cells in the brain, which helps regulate mood and anxiety.
• It is taken once or twice daily and usually takes two to six weeks to show its full effect; do not stop suddenly, as this can cause withdrawal symptoms.
• In people under 25, antidepressants including fluvoxamine can increase suicidal thoughts, especially in the first weeks of treatment or after a dose change. Anyone starting it should be watched closely for worsening mood or new thoughts of self-harm.
• Never combine fluvoxamine with an MAOI, and never take it with tizanidine: fluvoxamine strongly blocks the liver enzyme that breaks both down, and the combinations can cause serotonin syndrome or severe low blood pressure and sedation.

What fluvoxamine treats

Fluvoxamine treats obsessive-compulsive disorder (OCD) in adults and children. It is also used for social anxiety disorder, panic disorder and, in some countries, depression.

How fluvoxamine works

Nerve cells release serotonin and then reabsorb it. Fluvoxamine blocks that reabsorption (reuptake), so more serotonin stays active between nerve cells. Over several weeks this changes how mood- and anxiety-related brain circuits respond, easing OCD and anxiety symptoms.

Before you take it

• Do not take fluvoxamine within two weeks of stopping an MAOI, or start an MAOI within two weeks of stopping fluvoxamine.
• Tell your prescriber about a history of bipolar disorder, seizures, bleeding problems, or liver disease, and about every other medicine you take, since fluvoxamine strongly affects levels of drugs such as tizanidine, clozapine, theophylline and some benzodiazepines.
• Tell your prescriber if you or a family member has had suicidal thoughts, particularly if you are under 25.
• Avoid stopping fluvoxamine abruptly; your prescriber will usually reduce the dose gradually.

Side effects

Common effects include nausea, headache, drowsiness or insomnia, dry mouth, and sexual difficulties.

Stop and seek urgent medical care for any of these:

• New or worsening thoughts of self-harm, especially if you are under 25.
• Agitation, fast heartbeat, high fever, sweating or muscle twitching (possible serotonin syndrome).
• Severe drowsiness with a slow heartbeat or very low blood pressure, especially if taken with tizanidine.
• Unusual bruising or bleeding.

Safety essentials

• The under-25 suicidality warning applies to fluvoxamine: anyone in this age group should be checked in regularly during the first weeks of treatment and after any dose change.
• Never combine fluvoxamine with an MAOI, and avoid tizanidine, since fluvoxamine's strong inhibition of the CYP1A2 liver enzyme can raise both drugs to dangerous levels.
• Tell every prescriber and pharmacist you see that you take fluvoxamine, since it also raises levels of clozapine, theophylline and caffeine.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.