You are a hospital pharmacist who provides antiepileptic drug services to the Neurology clinic. Jessie, a 24-year-old lady who has just been married, is contemplating pregnancy in the future. She has a known medical history of generalized tonic clonic epilepsy since the age of 14. The frequency of convulsions is about once a month. Her current medication includes sodium valproate 400 mg twice daily. 

(a) She would like to seek your advice on the use of oral contraceptive pills ("OCP"). Please advise and explain if OCP is a safe contraceptive method for her. (2 marks) 

There is no drug interaction between sodium valproate and OCP, OCP is fine for her to take.

Anti-epileptic drugs (AED) which do interact with OCP are phenytoin, carbamazapine, phenobarbitone and topiramate.

Interactions between antiepileptic drugs and hormonal contraception - CNS Drugs 2002