Irinotecan and Phenobarbital, hyoscyamine, atropine, and scopolamine interaction
Irinotecan and Phenobarbital, hyoscyamine, atropine, and scopolamine: the Irinotecan prescribing label flags 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 Irinotecan (Camptosar) label · effective 2026-05-12
Early diarrhea may be accompanied by cholinergic symptoms which may be prevented or ameliorated by atropine.
Consider prophylactic or therapeutic administration of 0.25 mg to 1 mg of intravenous or subcutaneous atropine (unless clinically contraindicated).
Strong CYP3A4 Inducers Exposure to irinotecan or its active metabolite SN-38 is substantially reduced in adult and pediatric patients concomitantly receiving the CYP3A4 enzyme-inducing anticonvulsants phenytoin, phenobarbital, carbamazepine, or St.
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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.