Q. I was taking phenytoin, an extended release generic form of the anti-seizure drug Dilantin. On September 19, 2007, I had a grand mal seizure and upon admission to a local ER, my lab results indicated my phenytoin level was UNDETECTABLE! It was not just low, it was actually 0.0!
I had been faithfully taking my 200 mg capsule at bedtime every night. In fact, I had just swallowed that evening's dose right before the seizure.
I have reported this event to the FDA and the manufacturer. I have not been able to find out if the capsules were authentic or counterfeit.
I would encourage anyone taking phenytoin to have labs done to ensure you have an adequate level of the drug in your system. I am still taking the generic for seizure control because my insurance company mandates it. I have my phenytoin level checked monthly, however, to ensure that each bottle is actually providing an active ingredient.
A. Several years ago there was an article in the journal Neurology (Oct 26, 2004) documenting that an extended release generic phenytoin provided less active drug than the brand name Dilantin. Patients in Minnesota had been switched to the generic as a condition of their state employees health insurance. Several experienced seizures after the switch.
The FDA tells us that it is investigating this issue, but it has not issued an official report. In the meantime, your advice to monitor blood levels of phenytoin seems very sensible. No one should have to risk a seizure because of a flawed formulation.
Anyone who has had a problem with generic drugs may share the experience online here at www.peoplespharmacy.com and with the FDA at www.fda.gov/medwatch.