According to an analysis of prescription claims released recently by Medco Health Solutions, total generic dispensing rates for Allegra (fexofenadine HCl, Aventis), Arava (leflunomide, Aventis), Amaryl (glimepridie tablets, Aventis), and Zithromax (azithromycin tablets and azithromycin for oral suspension, Pfizer) topped 87% within 30 days after the drugs went off patent. The average generic fill rate at retail pharmacies for the group was more than 86%; at Medco's mail-service pharmacies the rate averaged 95%. Each of these drugs lost their patent within the last four months of 2005.
