I have nothing against generic medications. In fact, in many cases,they are just as good as brand name products, and they are frequently cheaper.On the other hand, there are also times when I find that generic chemicals arenot absorbed as well, or aren't as potent, or sometimes they aren't as welltolerated, and in these cases I write a big fat DAW (dispense as written) onthe prescription blank, and insist on the brand product as is my right as aprescribing physician.

But note that the practice of so-called “therapeutic substitution” isNOT the same thing as substituting an identical generic chemical. Not that I ama conspiracy theorist, but sometimes I wonder if insurance companiesdeliberately blur the distinction between generic equivalents and therapeuticsubstitutes so that the latter will be wrongly mistaken for the former.

Therapeutic substitution means replacing a drug in a given class witha generic alternative THAT IS NOT THE SAME DRUG. In other words, Lipitor may bereplaced by simvastatin, Altace (an ACE inhibitor for lowering blood pressure)with lisinopril, or Prevacid (Proton pump inhibitor that treats gastritis, PUD,and GERD) with omeprazole. In my clinical experience, this insurance-drivenpractice, though designed to save money, may actually cost more money in thelong run when patients experience unexpected side effects that they weren'tsuffering from previously. A case in point is statin drugs. Muscle aches arefairly common, but not entirely predictable, and more than one of my patients hasexperienced them while taking simvastatin but not with Lipitor, as well as viceversa. Such a patient, who is forcibly switched from one to the other and thenhas a side effect may be loath to take any statin drug after that, a boycottthat could easily lead to heart disease. Heart disease is a fair more expensiveoutcome for our healthcare system than any brand name drug.

I have found that some classes of drugs are more conducive totherapeutic substitution than others – in some classes, the drugs are fairlyinterchangeable. But it is not for an insurance company to decide which classesof drugs are which; it takes a physician with many years of careful experience.

My patients agree with me. So it is not surprising that a new surveyreleased by the National Consumers League and conducted by Harris Interactivereveals that nearly three-quarters of prescription drug users would be quiteconcerned if a drug were switched to another drug to treat the same conditionwithout their doctor's knowledge. One in five would be concerned even if theirdoctor knew about it. Two-thirds surveyed had never heard of this practice, andonly one in five would consider switching if they received an insurance letterrecommending the change, and most would still need to discuss it with theirdoctors before doing so.

The bottom line here is that physicians should be prescribing drugs,not insurance companies.