A dose of medication will reach a peak, or maximum, level in the blood 30 minutes to 4 or 6 hours after it is taken.
The peak time varies for different drugs.
For example a liquid, tablets, capsule or slow-release form.
In general, liquids are absorbed quickly.
Medications in slow-release forms are absorbed gradually over hours and produce the steadiest levels in the blood. These slow-release forms can be taken less often, once or twice a day.
Eating before a dose may also affect how long it takes to reach a peak level.
Category 1 – phenytoin, carbamazepine, phenobarbital, primidone For these drugs, doctors are advised to ensure that their patient is maintained on a specific manufacturer’s product
Category 2 – valproate, lamotrigine, perampanel, retigabine, rufinamide, clobazam, clonazepam, oxcarbazepine, eslicarbazepine, zonisamide, topiramate For these drugs, the need for continued supply of a particular manufacturer’s product should be based on clinical judgement and consultation with patient and/or carer, taking into account factors such as seizure frequency and treatment history
Category 3 - levetiracetam, lacosamide, tiagabine, gabapentin, pregabalin, ethosuximide, vigabatrin For these drugs, it is usually unnecessary to ensure that patients are maintained on a specific manufacturer’s product unless there are specific reasons such as patient anxiety and risk of confusion or dosing errors
Yes ask your doctor to prescribe you the brand name so the pharmacist will give you that AED
If your doctor writes the generic name of the AED on your prescription, ask if it can include the name of the specific drug company.
Try to use the same pharmacist each time as they may have a record of your AEDs and may ensure that you receive the same AED