Phenytoin

Phenytoin is an anti-seizure medication, also used as an antiarrhythmic agent, useful for preventing tonic-clonic (grand mal) seizures and focal seizures, though not absence seizures, and also used for some heart arrhythmias and neuropathic pain. It works by causing a voltage-dependent block of voltage-gated sodium channels in neurons, which blocks the sustained, high-frequency firing of action potentials that drives a seizure. German chemist Heinrich Biltz first made the compound in 1908, but its anticonvulsant value went unrecognized until 1938, when physicians H. Houston Merritt and Tracy Putnam found it controlled seizures without the sedative effects that came with phenobarbital, the standard treatment at the time. The Food and Drug Administration approved phenytoin in 1953, and the manufacturer Parke-Davis marketed it under the brand name Dilantin.