Dofetilide and Triamterene and hydrochlorothiazide interaction
Dofetilide and Triamterene and hydrochlorothiazide: the Dofetilide prescribing label flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Dofetilide label · effective 2026-04-24
The concomitant use of hydrochlorothiazide (alone or in combinations such as with triamterene) with dofetilide is contraindicated (see PRECAUTIONS, Drug-Drug Interactions ) because this has been shown to significantly increase dofetilide plasma concentrations and QT interval prolongation.
Hydrochlorothiazide (HCTZ) Alone or in Combination with Triamterene: (see CONTRAINDICATIONS ) Concomitant use of HCTZ alone or in combination with triamterene is contraindicated.
In the DIAMOND trials, 1252 patients were treated with dofetilide and diuretics concomitantly, of whom 493 died compared to 508 deaths among the 1248 patients receiving placebo and diuretics.
HCTZ 50 mg QD or HCTZ/triamterene 50/100 mg QD was co-administered with dofetilide (500 mcg BID) for 5 days (following 2 days of diuretic use at half dose).
In patients receiving HCTZ in combination with triamterene, dofetilide AUC increased by 30% and C max by 16%.
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.