UK regulator advises against substitution of epilepsy treatments

In an environment of generic prescribing, which is the UK norm, the Medicines and Healthcare products Regulatory Agency (MHRA) has issued advice for physicians not to switch patients on some anti-epileptic drugs (AEDs) between products from different manufacturers.  This guidance was communicated in a press release on 12 November 2013 (see link below), and is not limited to the switch from originator to cheaper generic drugs – but also includes switches between generics made by different manufacturers.

The agency have divided the drugs into 3 groups, with the strongest recommendation not to switch patients on category 1 AEDs (phenytoin, carbamazepine, phenobarbital, primidone).  MHRA recommends that decisions on switching between drugs in category 2 (valproate, lamotrigine, perampanel, retigabine, rufinamide, clobazam, clonazepam, oxcarbazepine, eslicarbazepine, zonisamide, topiramate) should be made based on the physicians clinical judgement and in consultation with the patient/carer.  And drugs in category 3 (levetiracetam, lacosamide, tiagabine, gabapentin, pregabalin, ethosuximide, vigabatrin) need only be exempted from switching in cases where the physician in concerned about patient anxiety or possible confusion in dosing.

While the agency highlights that there is no clear evidence of harm for patients who have their therapy switched, the Commission on Human Medicines (CHM) could not rule out “potential risks” for patients, including an increased risk of siezure or possibility of adverse effects.  So, could this advice set a precedent for branded prescribing in other therapy areas in the UK?  What might it mean for pricing of generics of these “exempted” drugs in the future?  And how will UK and EU patients and patient groups with other chronic diseases react, given the relative paucity of supporting evidence for these recommendations?

Pharma and generic/ biosimilar manufacturers will likely be watching the implemetation of these new recommendations closely.

Link to MHRA Press Release 

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