United Kingdom. In 1996 the Medicines Control Agency made recommendations to minimize the risk of severe oesophageal reactions in patients taking alendronic acid (Fosamax: Merck & Co.) for osteoporosis. The agency has continued to receive such reports and by July 1998 had received a total of 97 reports of oesophageal reactions (54 since August 1996). The agency stresses that:

Alendronic acid has very low bioavailability and needs to be taken at least 30 minutes prior to breakfast.

The tablet may lodge in the oesophagus and it is irritant to the oesophageal mucosa; it should not be chewed or sucked; it should be taken with a full glass of water and the patient should remain upright for at least 30 minutes afterwards. Use of alendronic acid is contraindicated in patients who are unable to sit upright or stand for 30 minutes.

Caution is required if the patient is also taking NSAIDs.

From 1 to 2% of patients taking alendronic acid may experience oesophageal reactions, even when following the dosing instructions. Patients should be warned to stop taking alendronic acid if oesophageal symptoms occur.

[See also Pharmaceuticals Newsletter Nos. 1&2, January & February 1998, Nos. 11&12, November & December, Nos. 1&2, January & February 1997 and Nos. 5/6, May/June 1996]

Reference: Current Problems in Pharmacovigilance Vol. 24, August 1998.