Methsuximide (Celontin) is a moderately priced drug used to control seizures in certain types of epilepsy. This drug is less popular than comparable drugs. It is available as a brand and generic. It is currently covered by some Medicare and insurance plans, but some pharmacy coupons or cash prices may be lower. Get Methsuximide for as low as $43.04, which is 85% off the average retail price of $286.31 for the most common version, by using a GoodRx coupon.