Should patients with epilepsy be changed from phenytoin capsules to tablets and vice versa?

Homepage

Search the NeLM

Browse by Categories:

Browse by NeLM area:

Original article by: Alexandra Denby

Publisher: London Medicines Information Service

Keywords: phenytoin, pharmacokinetics

Date published: 09/02/2012 08:30

Review date: 28/02/2014 08:30

Summary

by: Alexandra Denby

NICE Guidance, and many European guidelines, do not recommend changing the formulation or brand of AED due to the risk of loss of seizure control or increased adverse events.
Different preparations may vary in bioequivalence and bioavailability with the increased potential for reduced effect or excessive side effects.
It is recommended that patients are prescribed anticonvulsants by brand name to avoid a change in preparation that can occur with generic substitution. This is particularly important for antiepileptics which have narrow therapeutic ranges, such as phenytoin.
The decision to use a particular brand or formulation of phenytoin should ideally be made at the outset of treatment.
Patient’s plasma levels should be monitored closely and doses adjusted if necessary following any switch in formulation.

About this library entry

Category: 4.8.1 Control of epilepsy | Epilepsy | FAQs

NeLM area: Evidence > Medicines Q & A