Zyprexa, Zyrtec prescription mix-ups result in hospitalizations

- February 9, 2005

Eli Lilly and Co.'s best selling drug Zyprexa and Pfizer Inc.'s Zyrtec, the most prescribed antihistamine in the United States, have been interchanged because of name similarity, dosage guidelines and close proximity on pharmacy shelves.

According to Lilly officials in a letter dated January 26 to psychiatrists and pharmacists, the company has received 79 reports of drug prescription mix-ups since Zyprexa was introduced in 1996. Zyprexa is approved to treat schizophrenia and bipolar disorder, and patients with psychological disorders who take Zyrtex instead of Zyprexa risk relapse.

A Lilly spokeswoman said the company has not received any reports of relapse, but the most frequently reported effect from the drug mix-ups are excessive sleepiness, a potential side effect for both drugs. In some cases, the drug errors required hospitalization.

Lilly changed Zyprexa labeling from all capital letters to read ZyPREXA, highlighting the lettering in yellow to add more distinction between Zyrtec labels. The company said it has also begun mailing direct and trade journal advertising and other measures to alert pharmacists of the potential drug errors.