You've stumped me on this one! But one our experts may know the answer.   The only allergy drug that came up in my research was and antihistamine called Seldane (the generic name is terfenadine). The FDA wanted to pull the drug because it caused potentially fatal drug interactions involving the heart. The recommendation to remove the drug was first made in 1997.   It was replaced by Allegra, which was deemed safe. But Merck did not manufacture either drug. Hoescht Marion Roussel and Baker Norton Pharmaceuticals, which made Seldane, voluntarily removed it from the market in 1998 -- replacing it with Allegra.   Is this the drug you were asking about?