Despite having a prescription for a specific brand medication, we are often served a generic drug and, often but not always, told that it is “the same” but less expensive. Is it really? Some generics of old medications such as the benzodiazepines and the tricyclics are really inexpensive, with most of the bill going toward pharmacy costs. As an example, the price of a low dose of amitriptyline for the management of chronic pain for 1 month is probably not much more than that of a cappuccino in a fancy bistro. In contrast, the savings on newer molecules introduced immediately after patent expiration are not that considerable. This is, in part, due to the fact that generic companies, like brand companies, are in the business to make money. In addition, the chemical synthesis of some medications may be quite cumbersome and expensive. For instance, generic companies stayed away from making the commonly used antibiotic cefaclor because its synthesis involves an intermediate that is explosive.
After a patent for an original medication has expired, companies producing generics initially have to present data showing that their product has 80%–125% bioavailability of the original drug. Variations within that range for most illnesses and most patients probably have no clinical consequences. In some cases, however, a switch to a generic will produce a significant difference in the control of a disorder, for instance, in the management of epilepsy when the outcome is not a mere alteration of a biochemical parameter. The change can be quite obvious indeed. In the management of high blood pressure, whereby the primary target parameter can easily be monitored by the patient at no cost, the loss of adequate control can be easily documented. In the United States, some health management organizations will pay for some brand medications, despite the availability of generics, because