Last fall, an independent laboratory, prompted by a flurry of consumer complaints, presented evidence that a generic version of the once-a-day antidepressant Wellbutrin XL may be less effective than the original at reducing some patients' depressive symptoms. An agency spokeswoman said the FDA is investigating the matter and will make its findings public when the inquiry is complete.
In a report released today, the New York-based ConsumerLab.com, which conducted the Wellbutrin XL analysis, also urges the FDA to review the performance of a new generic for Toprol XL, a once-a-day version of a high blood pressure drug that is the fifth most-prescribed medicine in the United States. That challenge comes after dozens of patients complained to the People's Pharmacy -- a multimedia source of information about drugs and supplements -- of erratic spikes in blood pressure and side effects after they had switched from Toprol XL to a new generic version of the drug.
Cardiologists, meanwhile, have been growing more vocal in their concern about "generic substitution" for newer, brand-name drugs. They have had long-standing worries about the effect of switching patients whose blood has been thinned with Coumadin to generic versions of the anticoagulant, including warfarin. Many have warned that patients with heart arrhythmias should be switched to generic drugs only when necessary. And many cardiologists view the swelling field of generic blood-pressure and cholesterol drugs with some distrust.
The American Assn. of Clinical Endocrinologists, the Endocrine Society and the American Thyroid Assn. joined voices in 2004 to warn that patients with hypothyroidism could be harmed by switching among the many generics used to treat the condition. And physicians who care for organ transplant recipients have opposed generic substitution of immunosupressant drugs for their patients without a transplant specialist's prior approval. Societies that represent these doctors have been active in seeking state laws that would limit such switches.
Kathleen Jaeger, president and chief executive of the Generic Pharmaceutical Assn., dismisses all of these debates as "misinformation campaigns" masterminded by brand-name pharmaceutical companies. As these companies' most profitable medicines face competition from generic upstarts, Jaeger said, they seek to "extend their monopoly" by sowing doubt in the minds of physicians, pharmacists and patients about the quality of the cheaper substitutes.
