Under what condition is Ketoconazole contraindicated?

Under what condition is Ketoconazole contraindicated?

• A. When taken with azithromycin
• B. When taken with erythromycin
• C. When taken with penicillin
• D. When taken with tetracycline

Answer: (B)

Ketoconazole is contraindicated when taken with erythromycin due to the potential for significant drug interactions. Erythromycin is a known inhibitor of the cytochrome P450 3A4 enzyme, which is responsible for the metabolism of many drugs, including ketoconazole. When ketoconazole is taken alongside erythromycin, it can lead to increased plasma levels of ketoconazole, which may enhance the risk of adverse effects and toxicity. This interaction emphasizes the importance of understanding pharmacokinetic properties when safety concerns arise with multiple medications. Other options do not carry the same level of concern regarding contraindications. While azithromycin also affects the same metabolic pathways, it is generally not considered to have the same pronounced effect as erythromycin on ketoconazole's metabolism. Penicillin and tetracycline do not have significant clinical interactions with ketoconazole that would contraindicate their concurrent use.

Ketoconazole is contraindicated when taken with erythromycin due to the potential for significant drug interactions. Erythromycin is a known inhibitor of the cytochrome P450 3A4 enzyme, which is responsible for the metabolism of many drugs, including ketoconazole. When ketoconazole is taken alongside erythromycin, it can lead to increased plasma levels of ketoconazole, which may enhance the risk of adverse effects and toxicity. This interaction emphasizes the importance of understanding pharmacokinetic properties when safety concerns arise with multiple medications.

Other options do not carry the same level of concern regarding contraindications. While azithromycin also affects the same metabolic pathways, it is generally not considered to have the same pronounced effect as erythromycin on ketoconazole's metabolism. Penicillin and tetracycline do not have significant clinical interactions with ketoconazole that would contraindicate their concurrent use.