Terbinafine and Venlafaxine interaction
Terbinafine and Venlafaxine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Venlafaxine (Venlafaxine Hydrochloride) label · effective 2025-01-31
Therefore, the potential exists for a drug interaction between drugs that inhibit CYP2D6-mediated metabolism of venlafaxine, reducing the metabolism of venlafaxine to ODV, resulting in increased plasma concentrations of venlafaxine and decreased concentrations of the active metabolite.
Drugs that Inhibit Cytochrome P450 Isoenzymes CYP2D6 Inhibitors: In vitro and in vivo studies indicate that venlafaxine is metabolized to its active metabolite, ODV, by CYP2D6, the isoenzyme that is responsible for the genetic polymorphism seen in the metabolism of many antidepressants.
CYP2D6 inhibitors such as quinidine would be expected to do this, but the effect would be similar to what is seen in patients who are genetically CYP2D6 poor metabolizers [see Clinical Pharmacology ( 12.3 )] .
Drugs Metabolized by Cytochrome P450 Isoenzymes CYP2D6 In vitro studies indicate that venlafaxine is a relatively weak inhibitor of CYP2D6.
Therefore, no dosage adjustment is required when venlafaxine is coadministered with a CYP2D6 inhibitor.
From the Terbinafine (Terbinafine Hydrochloride) label · effective 2026-01-01
Drugs predominantly metabolized by the CYP450 2D6 isozyme include the following drug classes: tricyclic antidepressants, selective serotonin reuptake inhibitors, beta-blockers, antiarrhythmics class 1C (e.g., flecainide and propafenone) and monoamine oxidase inhibitors Type B.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.