Thioridazine and Fluvoxamine

Desk tier: Avoid together

Mechanism: weak CYP2D6 inhibition of clearance (↑ exposure)

“certain other drugs (e.g., fluvoxamine, propranolol, and pindolol) appear to appreciably inhibit the metabolism of thioridazine … thioridazine is contraindicated with these drugs”

Thioridazine HCl tablets, section CONTRAINDICATIONS. DailyMed label

Why this grade

Thioridazine HCl tablets label, Contraindications

The Thioridazine HCl tablets label lists this combination under Contraindications. CONTRAINDICATIONS: "certain other drugs (e.g., fluvoxamine, propranolol, and pindolol) appear to appreciably inhibit the metabolism of thioridazine … thioridazine is contraindicated with these drugs" Retrieved from DailyMed 2026-09-27.

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FDA interaction table

FDA's example-interaction table lists Fluvoxamine as a weak CYP2D6 inhibitor. FDA grades the roles; the severity tier on this row is the desk's rule. Table content current as of 2026-05-29.

Open source

Fluvoxamine label, 4 Contraindications

The Fluvoxamine label calls this combination contraindicated: "Coadministration of thioridazine, tizanidine, pimozide, alosetron, or ramelteon with fluvoxamine maleate extended-release capsules is contraindicated" Retrieved from DailyMed 2026-10-02.

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PMID 25974703

2015 Clin Pharmacol Ther. CPIC SSRIs. Flip 2C19 on this desk for citalopram / escitalopram.

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Open this pair in the desk

All pairs for Thioridazine · Fluvoxamine

Enzyme behind this pair: CYP2D6

Educational reference only. Not FDA-cleared. The Prescribing Information governs.

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