MAJOR — Use With Caution
FDA-documented interaction. Fluvoxamine is the strongest CYP1A2 inhibitor. Clozapine dose must be dramatically reduced (often by 2/3 to 3/4). Some clinicians intentionally use this interaction to boost clozapine levels, but only with very careful monitoring.
Evidence level: STRONG
Fluvoxamine (Luvox) is the most dangerous SSRI to combine with clozapine because it very powerfully blocks the enzyme that breaks down clozapine. Clozapine levels can increase 5-10 times, causing life-threatening toxicity.
Fluvoxamine is the most potent CYP1A2 inhibitor among SSRIs. Clozapine is primarily metabolized by CYP1A2. Fluvoxamine can increase clozapine levels 5-10 fold. FDA clozapine label warns.
If prescribed both, your clozapine dose must be drastically reduced and blood levels monitored frequently. Some psychiatrists deliberately use this interaction to raise clozapine levels, but only under close supervision.
Take Fluvoxamine at the same time each day — morning is most common to avoid sleep disruption. Clozapine follows its prescribed schedule. SSRIs have a long half-life, so consistency matters more than the exact hour.
Higher risk for: elderly, those on multiple serotonergic drugs, people with liver impairment, CYP2D6 poor metabolizers, recent dose changes, or concurrent use of MAOIs or triptans.
Extreme sedation, seizures, dangerously low blood pressure, rapid heart rate, excessive drooling, confusion, respiratory depression
Reduce clozapine dose by 2/3 to 3/4 when adding fluvoxamine. Monitor clozapine levels weekly initially. This interaction is sometimes used therapeutically but requires expert management.
Discuss this combination with your prescriber. They may adjust timing, dosing, or switch to an alternative with fewer interaction risks. Never stop an antidepressant abruptly — taper under medical guidance.
Fluvoxamine (Luvox) is the most dangerous SSRI to combine with clozapine because it very powerfully blocks the enzyme that breaks down clozapine. Clozapine levels can increase 5-10 times, causing life-threatening toxicity.
Take Fluvoxamine at the same time each day — morning is most common to avoid sleep disruption. Clozapine follows its prescribed schedule. SSRIs have a long half-life, so consistency matters more than the exact hour.
Extreme sedation, seizures, dangerously low blood pressure, rapid heart rate, excessive drooling, confusion, respiratory depression
Discuss this combination with your prescriber. They may adjust timing, dosing, or switch to an alternative with fewer interaction risks. Never stop an antidepressant abruptly — taper under medical guidance.
Reduce clozapine dose by 2/3 to 3/4 when adding fluvoxamine. Monitor clozapine levels weekly initially. This interaction is sometimes used therapeutically but requires expert management.
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