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New Research Shows Generic Wellbutrin Many Not be as Effective as Brand Name Medication

Oct 12, 2007 | Parker Waichman Alonso LLP

A generic version of Wellbutrin might not treat depression as effectively as the name brand medication, and that could be putting patients at risk.  A new study comparing Teva Pharmaceutical’s generic Budeprion XL with Wellbutrin XL found that although the generic antidepressant contained the same active ingredient as the brand name drug, it performed differently than Wellbutrin XL in lab tests.  The new research raises serious questions about the way the Food & Drug Administration (FDA) approves all generic prescription drugs.

The investigation into Budeprion XL was conducted by the consumer advocacy website ConsumerLab.com, after the writers of a syndicated newspaper column reported receiving hundreds of complaints from former Wellbutrin XL users that Budeprion XL was not working as well.  ConsumerLab.com performed lab analysis of the antidepressants, and found that both versions contained the stated amount of the active ingredient bupropion. But differences between Wellbutrin XL and Budeprion XL became apparent when the drugs were subjected to “dissolution testing”.  Both Wellbutrin XL and Budeprion XL are time-released medications, meaning that the active ingredient is released into a patient’s system over a period of many hours.  In the case of Wellbutrin XL, the tests showed that in two hours, only about 8% of the bupropion was released.   But in the case of the generic Budeprion XL, 34% of its active ingredient had already been released in the same period.    Four hours into the dissolution test, and Wellbutrin had only released 25% of its active ingredient, but for the generic drug, half of the bupropion was already released.

This could explain why some people who switch from Wellbutrin XL experience difficulties on Budeprion XL.  Getting a higher dose of brupropion up front could have caused the headaches, irritability and nausea so many Budeprion XL users complained of.  And even more serious problems, like a return of depression or suicidal thoughts, could be the result of less medication entering the patients’ bloodstreams later in the day.

As if the results of the Wellbutrin/Budeprion study aren’t disturbing enough, the ConsumerLab.com researchers warned that such problems could be typical of other generic drugs.  That’s because the FDA does not subject these medications to the same level of scrutiny as name brand medications.  For example, when a pharmaceutical company wants to bring a new brand name drug to market, the company must demonstrate its effectiveness and safety through extensive clinical trials.  But to sell a generic version, a company is only required to provide the FDA with lab data and test results from  24 to 36 volunteer subjects that shows the drug works similarly to the name brand medicine. The ConsumerLab.com findings now have some doctors and consumer advocates wondering if the FDA’s approval standards for generic drugs are adequate.

Generic drugs are generally much less expensive than name brands.  For example, a three month supply of Budeprion XL costs less than $60, while the same amount of Wellbutrin XL costs well over $200.   As a result many insurance companies will only pay for a generic version of a drug if one is available, and the FDA has planned to speed up approvals for generics as way to help consumers deal with the high cost of prescription drugs.    But as the ConsumerLab.com study demonstrates, not all drugs are equal.   For that reason, anyone who switches from a brand name prescription medication to a generic version should report any new side effects or other issues to their doctors.