Drug interactions
ketoconazole + terfenadine
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.
Overview
Torsades risk; contraindicated (historical).
Mechanism of action
CYP3A4 inhibition → ↑ terfenadine.
Clinical management
Avoid (drug largely withdrawn).
Drug reference
References
Frequently asked questions
Can I take ketoconazole with terfenadine?
The interaction is rated: Contraindicated. Torsades risk; contraindicated (historical).
How serious is the interaction between ketoconazole and terfenadine?
The interaction is rated: Contraindicated. Evidence level: High.
How is the interaction between ketoconazole and terfenadine managed?
Avoid (drug largely withdrawn).
Why do ketoconazole and terfenadine interact?
CYP3A4 inhibition → ↑ terfenadine.
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