Drug Interaction Report

GENERALLY AVOID: Because irinotecan has been reported to cause diarrhea in the majority of treated patients, the use of laxatives may not be appropriate during irinotecan therapy.

MANAGEMENT: In patients requiring laxatives for constipation associated with narcotic administration, the standard regimen may be continued under supervision of the clinician. However, patients should be advised to inform their physician of any changes in their bowel habit so that dosage adjustments or discontinuation of laxatives may be done promptly.

ADJUST DOSING INTERVAL: Bulk-forming laxatives such as guar gum, psyllium, polycarbophil, or methylcellulose may affect the bioavailability of concomitantly administered substances due to their effect on the rate of gastrointestinal transit and gastric emptying.

MANAGEMENT: In general, oral medications should be administered at least 2 hours before or 2 hours after dosing of the bulk-forming laxative.