Assignment task:
Katie Karlsson, a 15 year old girl, has recently been diagnosed with epilepsy by her neurologist. About six years ago she suffered a slight concussion as the result of a fall when skiing. There were no further neurological problems until two weeks ago, when she reported experiencing a strange sensation. This was followed by a tonic-clonic seizure. ???????
The neurologist commences Katie on anticonvulsant medication. She is commenced on 300mg phenytoin PO daily.
After several weeks of therapy, Katie has another tonic-clonic seizure and phenobarbital (phenobarbitone) 150mg PO daily is added to her treatment program. This brings the seizures under control.
Given your knowledge of these drugs and their use in seizure management, what is the likely rationale behind adding a second anticonvulsant?