Drug interactions
Hydrochlorothiazide + Procainamide
Severity: Moderate
Hydrochlorothiazide and Procainamide: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Procainamide and its active metabolite NAPA are renally eliminated, and thiazide-induced hypokalemia or reduced renal clearance may raise levels or proarrhythmic risk. Hypokalemia also increases the risk of QT prolongation and torsades.
What this interaction means in plain words
Hydrochlorothiazide and Procainamide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Possible reduced renal clearance of procainamide/NAPA, plus thiazide-induced hypokalemia increasing proarrhythmic risk.
What to do
Monitor ECG, QT interval, potassium, magnesium and procainamide/NAPA concentrations; correct electrolytes.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Hydrochlorothiazide
Frequently asked questions
Can I take Hydrochlorothiazide with Procainamide?
MediHelp rates the interaction as moderate. Hydrochlorothiazide and Procainamide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Procainamide and its active metabolite NAPA are renally eliminated, and thiazide-induced hypokalemia or reduced renal clearance may raise levels or proarrhythmic risk. Hypokalemia also increases the risk of QT prolongation and torsades.
How serious is the interaction between Hydrochlorothiazide and Procainamide?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor ECG, QT interval, potassium, magnesium and procainamide/NAPA concentrations; correct electrolytes.
What other medicines interact with Hydrochlorothiazide?
MediHelp also lists interactions of Hydrochlorothiazide with, for example, Dofetilide, Amifostine, Amiodarone. The full list is on the Hydrochlorothiazide page.
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