A to Z of MSPhenytoin

Product name

Epanutim

Phenytoin is an anticonvulsant drug that works on the brain and spinal cord. Its main use is in epilepsy. In MS it can be used to treat trigeminal neuralgia or other painful sensations (dysaethesia) if other approaches have not worked.

How phenytoin is given

Phenytoin is given orally as tablets.

Phenytoin can remain in the body for some time after treatment has stopped so it is important to taper off treatment gradually rather than stopping abruptly.

Side effects and contraindications

Constipation, mild dizziness, mild drowsiness. These are normally transitory and will pass as an individual adjusts to the medication.

Phenytoin may affect an individual's ability to metabolise vitamin D - a GP may advise supplements. Phenytoin may reduce the effectiveness of some oral contraceptives.

People should not take phenytoin if they have liver dysfunction. It should also be avoided during pregnancy or whilst still breastfeeding.