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Is Generic Prescribing Acceptable in Epilepsy?

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Abstract

There is considerable debate about the role of generic prescribing for people with epilepsy. The arguments go beyond simple considerations of cost on one hand and the possibility of toxicity or loss of seizure control on the other. The concepts of bioavailability and bioequivalence require further consideration. The measures that are currently used may not apply equally well to all situations. For example, additional measures may be needed for controlled-release preparations and in the other special cases. There is an extensive literature on the bioequivalence of various phenytoin preparations. This anticonvulsant drug is poorly soluble in water, has nonlinear kinetics and has a narrow therapeutic range, implying that problems with bioequivalence are likely to occur. This is borne out by clinical experience. There are a few published investigations on carbamazepine. The systematic studies, on the whole, fail to show major differences in bioequivalence between the various formulations. There is sparse information on the comparison between generic and proprietary formulations of other anticonvulsant drugs. Whatever arguments might be put forward supporting brand name or generic prescribing, there are strong reasons for recommending tight control on the consistency of anticonvulsant drugs, both generic and proprietary.There is also a strong case for ensuring that the physician who signs the prescription remains in control of the situation and that any decisions that the physician makes should be based on accurate and reliable information.

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Acknowledgements

The tremendous support and assistance given by Professor Alan Richens is warmly acknowledged. The British Epilepsy Association provided an additional and useful literature search. Letters were written to a number of pharmaceutical companies manufacturing anticonvulsant drugs. Of these, Parke Davis, Novartis, Glaxo Wellcome, Sanofi Winthrop and AstraZeneca provided helpful information.

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  1. St Piers Lingfield, St Piers Lane, Lingfield, Surrey, and, Centre for Epilepsy, Maudsley Hospital, London, RH7 6PW, England

    Frank M.C. Besag

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Besag, F.M. Is Generic Prescribing Acceptable in Epilepsy?. Drug-Safety 23, 173–182 (2000). https://doi.org/10.2165/00002018-200023030-00001

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