Two Drugmakers Alert Doctors About Potential Adverse Events

Two drugmakers have sent "Dear Healthcare Professional" letters to physicians alerting them about the potential for medication mix-ups and adverse drug interactions involving their products.

Eli Lilly issued an alert about possible medication errors involving its antipsychotic Zyprexa (olanzapine) and Pfizer's antihistamine Zyrtec (cetirizine HCl). Lilly has received reports of medication dispensing or prescribing errors, including instances where Zyprexa was incorrectly dispensed for Zyrtec and vice versa, according to the company's letter, posted on the FDA's MedWatch website.

Although there are considerable differences between the indications for the two drugs, many similarities exist that could contribute to medication errors, Lilly said. To reduce the potential for future errors, Lilly has taken several actions, including changing the label of the 10-mg bottles from ZYPREXA to ZyPREXA, launching a direct mail campaign to pharmacists, and placing journal ads focused on the dispensing-error potential.

Meanwhile, Roche Laboratories has issued an "important drug interaction warning" involving a tuberculosis drug and the company's HIV treatments. According to the letter, posted on the MedWatch site, the tuberculosis drug rifampin should not be administered to patients also receiving saquinavir/ritonavir (ritonavir boosted saquinavir) as part of combination antiretroviral therapy for HIV infection. Drug-induced hepatitis with marked transaminase elevations has been observed in healthy volunteers receiving rifampin 600 mg once daily in combination with ritonavir 100 mg/saquinavir 1000 mg twice daily, Roche said.

For more information, go to the FDA's MedWatch website at http://www.fda.gov/medwatch/SAFETY/2005/safety05.htm#Agrylin (http://www.fda.gov/medwatch/SAFETY/2005/safety05.htm#Agrylin).