Prescribing generically: how to decide

Which medicines should not be prescribed generically and what are biosimilar medicines? These are some of the questions considered in a useful new bulletin from the MeReC on prescribing generically in primary care. It explains about generics, branding, costs and reimbursement, and the now-abandoned proposals for generic substitution in primary care in England (see here). Generic medicines given a licence have been deemed by the regulator to be as safe as the branded medicine and clinically equivalent, when used at the same dose for the same condition. There is little evidence to back concerns that switching has adverse effects.

There are some circumstances in which a specific product, branded or generic, should be prescribed and these include: drugs with a narrow therapeutic index such as phenytoin (although there is little good quality evidence to support concerns about these medicines, the concerns remain and the consequences are potentially serious); some modified-release or extended-release drugs (because of the differences resulting from different manufacturers’ formulations); certain administration devices such as some CFC-free beclometasone inhalers; multiple ingredient products such as oral contraceptives and emollient creams; ‘biosimilar’ medicines; if differences in appearance might lead to confusion or anxiety, reducing adherence to long–term medications; to avoid specific inactive formulation ingredients where they are not tolerated.