Many people assume that if they've had a seizure, they have epilepsy. It seems to make sense, then, that they should take an anti-epileptic medication.
However, it's important to know that having a seizure does not mean you have epilepsy. Given the proper combination of a seizure focus, and a lowered seizure threshold, anyone can have a seizure. For example, many alcoholics have had seizures when they've withdrawn from alcohol. This doesn't mean they have epilepsy. They don't need another medication-- they need to stop drinking alcohol.
Epilepsy means you've had more than one "unprovoked" seizure, which means that there was no reason to believe that the seizure threshold was lowered. So if your seizure can be explained by something like low blood sugar, a medication or illicit drug, or a medical illness, then you may not require medication.
On the other hand, sometimes a seizure is provoked by something like a stroke, the results of which are not going to go away. In this case, the stroke has caused a permanent seizure focus, and anti-epileptic medication might make sense.
To learn more about what causes seizures, read here:What Causes Seizures?