Generics Versus Brand Names

The FDA allows a variance of 20% when it comes to generic medicationsBrand named drugs are becoming more and more expensive these days and many people just can’t afford them.  Often insurance companies won’t pay for a brand name if a generic equivalent is available, so more than ever people are faced with the question–are the generics equally effective and safe?

Both the FDA and generic drugmakers say that the generics are clinically identical to the brand named medications, but is this always the case?

Generic drugs have to meet the requirements of the FDA which requires ”90% confidence intervals for maximal concentration and the area under the concentration-time curve must be no less than 80% and no more than 125% of the means for the branded drug”, according to MedPage Today.  In other words, yes there can be some variation. 

This variation may or may not be a problem.  It can be serious if the disease requires very specific blood levels of the drug, however, such as in a seizure disorder.  

Carbamazepine (Tegretol) is a drug used to treat seizure disorders.  The levels of the drug need to be predictable, reliable and effective, otherwise a seizure may occur.  In a recent study at John Hopkins University, generic versions varied markedly in FDA-sanctioned bioequivalence studies.  So in the case of carbamazepine, this variability could have significant clinical consequences for patients who switch from the branded product or from one generic version to another.

Another drug of concern is generic thyroid.   Fortunately a blood test (TSH) can determine if you’re getting the right amount of thyroid medication, but it should only be done two months after taking the medication on a daily basis. Also, the problem might arise if the pharmacy switches generic brands, which they have been known to do.  So if you have a choice, choose the brand name when it comes to thyroid medicine. If you’re forced to take the generic option, let your doctor know and pay attention to the color and appearance of the pill.  If it ever changes, ask the pharmacist.  If the pharmacy does switch generics, let your doctor know so a blood test can be scheduled. 

 As a health care practitioner, I’m concerned about generic alendronate (Fosamax).  While the generic version may contain the correct amount of the drug, you may not be getting the absorption needed for it to be effective.  This is particularly important for medications that have poor GI absorption to begin with. The absorption of the generic may be even worse than the brand name with the end result being little or no benefit when it comes to improving bone density. 

Venlafaxine (Effexor), a popular drug for depression was recently studied by Franck Chenu, PharmD, PhD, of the University of Ottawa.  The researchers found that the side effects of the generic version was three times more common than with the branded version, Effexor. Their findings were reported in the July 2009 issue of the Journal of Clinical Psychiatry.

When it comes to generics it’s always a good idea to talk it over with your doctor before you make the decision of generic versus brand name.  And if you can only afford generic, let your doctor know. 

Source: “AAN: Wide Variability in Generic Versions of Epilepsy Drug”, MedPage Today, May 1, 2009
Source: “Generics versus Brands: Are They Really Equivalent?”, MedPage Today, August 25, 2009

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