The Medicines and Healthcare products Regulatory Agency (MHRA) has written to healthcare professionals to provide information about switching between different manufacturers’ products of antiepileptic drugs (AEDs). This includes switching between branded products and generic products, and between different generic products of a particular drug.
Following a review of the available evidence and consideration of the bioavailability and pharmacokinetic characteristics of the different drugs it has been suggested that they could be classified into three categories:
- Category 1 (Phenytoin, carbamazepine, phenobarbital, primidone). For these drugs, doctors are advised to ensure that their patient is maintained on a specific manufacturer’s product.
- Category 2 (Valproate, lamotrigine, perampanel, retigabine, rufinamide, clobazam, clonazepam, oxcarbazepine, eslicarbazepine, zonisamide, topiramate). For these drugs the need for continued supply of a particular manufacturer’s product should be based on clinical judgement and consultation with patient and/or carer taking into account factors such as seizure frequency and treatment history.
- Category 3 (Levetiracetam, lacosamide, tiagabine, gabapentin, pregabalin, ethosuximide, vigabatrin). For these drugs it is usually unnecessary to ensure that patients are maintained on a specific manufacturer’s product unless there are specific concerns such as patient anxiety, and risk of confusion or dosing errors.
A patient information leaflet has been prepared and provides a summary of what these changes means.
Action: Clinicians will already be aware of the need to prescribe by brand for the specified medicines. This document is helpful in indicating where more flexible prescribing can be considered.
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