United States of America. The manufacturer of the gastrointestinal motility stimulating agent, cisapride (Propulsid: Janssen), indicated for night-time heartburn, has issued a “Dear Doctor” letter concerning revisions to the sections on Contraindications and Drug Interactions in the product information.

BOXED WARNING & CONTRAINDICATIONS

Two new medical conditions have been added to the Contraindications and Boxed Warning sections of cisapride (Propulsid) labelling. These are:

• known family history of congenital long QT syndrome; and
• clinically significant bradycardia.

The purpose of these additions is to further clarify the contraindicated medical conditions for cisapride (Propulsid). These conditions are independent risk factors for QT prolongation.

DRUG INTERACTIONS

• Coadministration of grapefruit juice with cisapride increases the bioavailability of cisapride and concomitant use should be avoided.

This addition is based on the results of a drug interaction study conducted in normal volunteers, which demonstrated that the coadministration of grapefruit juice and cisapride resulted in an increased bioavailability of cisapride.

[See also Pharmaceuticals Newsletter No. 4, April, No. 9, September 1995, No. 3, March 1996, Nos. 7&8, July & August 1997 and Nos. 7&8 July & August 1998]

Reference: “Dear Doctor” letter dated 1 June 1999. [http://www.fda.gov/medwatch/safety/1999/propul.htm]