Itraconazole and Loperamide interaction

Itraconazole and Loperamide: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.

Moderate

Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.

What the FDA labels say

From the Itraconazole (Tolsura) label · effective 2025-04-23

Moderate

Aprepitant Loperamide Monitor for adverse reactions.

Drug interactionsnames LoperamideView label on DailyMed

From the Loperamide (Loperamide Hydrochloride) label · effective 2026-07-28

Moderate

CYP3A4 and CYP2C8 Inhibitors When multiple doses of both 100 mg itraconazole and 600 mg gemfibrozil twice daily were administered with a single 4 mg dose of loperamide hydrochloride, the mean peak plasma concentration and the systemic exposure to loperamide was increased by 4.2-fold and 12.6-fold, respectively.

Drug interactionsnames ItraconazoleView label on DailyMed
Moderate

Drug Interactions Effects of Other Drugs on Loperamide Concomitant use of loperamide hydrochloride capsules with inhibitors of CYP3A4 (e.g., itraconazole) or CYP2C8 (e.g., gemfibrozil) or inhibitors of P-glycoprotein (e.g., quinidine, ritonavir) can increase exposure to loperamide.

Drug interactionsby drug classView label on DailyMed
Moderate

CYP3A4 Inhibitors Itraconazole Concomitant administration of multiple doses of 100 mg itraconazole twice daily, an inhibitor of both CYP3A4 and P-glycoprotein, with a single 4 mg dose of loperamide hydrochloride increased the peak plasma concentration and the systemic exposure to loperamide by 2.9-fold and 3.8-fold, respectively.

Drug interactionsby drug classView label on DailyMed
Moderate

P-glycoprotein Inhibitors Concomitant administration of a 16 mg single dose of loperamide hydrochloride with a 600 mg single dose of quinidine or ritonavir, both of which are P-glycoprotein inhibitors, resulted in a 2- to 3-fold increase in loperamide plasma concentrations.

Drug interactionsby drug classView label on DailyMed
Moderate

Due to the potential for enhanced CNS adverse reactions when loperamide is coadministered with quinidine and with ritonavir, caution should be exercised when loperamide hydrochloride capsules are administered at the recommended dosages (2 mg, up to 16 mg maximum daily dose) with P-glycoprotein inhibitors.

Drug interactionsby drug classView label on DailyMed

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Not 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.