Dilantin, one of the oldest and most frequently used antiepileptic drugs, may lead over time to cerebellar atrophy and resulting motor dysfunction.

Dilantin is Pfizer Inc.’s brand name for the drug phenytoin. It’s used to control certain types of seizures that are caused by epilepsy or occur during or after neurosurgery but has some potentially serious side effects.

One of the many known risks of long-term Dilantin use is the development of cerebellar atrophy. This condition is a type of degeneration of the cerebellum, the part of the brain that controls balance, posture, and voluntary muscle movement.

Patients with cerebellar atrophy may have difficulty walking, speaking, swallowing food, or performing other voluntary movements.

Cerebellar Atrophy Treatment

Treatment for cerebellar atrophy focuses on removing the cause and helping the patient adjust to their loss of motor function. Physical therapy may help the patient restore some control of movement or learn to use assistive devices.

Occupational therapy may be necessary to help the patient re-develop skills necessary to hold a job. In more advanced cases of cerebral atrophy, the presence of a personal assistant may be necessary.

One case study published recently tells the story of a 16-year-old boy with cerebellar atrophy. He initially showed up at an emergency room with a viral infection, as evidenced by symptoms of fever and weakness.

He recovered from the viral fever but then complained of difficulty walking. Doctors noted his 10-year history of seizures, treated with phenytoin.

His serum phenytoin level was high, and an imaging study of his brain revealed cerebellar atrophy; a causality assessment revealed a probable association between the phenytoin and the boy’s adverse drug reaction. The doctors immediately took him off of phenytoin and switched him to valproic acid.

The authors of the case study noted that there have been some reports of cerebellar atrophy associated with phenytoin use, usually reported in cases where the drug serum levels are above the therapeutic range. The authors say that regular monitoring for adverse drug reaction should be considered in patients subject to long-term phenytoin exposure.

The effects that cerebellar atrophy can have on a patient’s life are not hard to imagine. Loss of motor control can have a profound effect on a person’s ability to maintain activities of daily living.

Personal relationships can be strained, and the patient’s ability to work and earn income may be in jeopardy. For some patients already living with epilepsy, the risk of cerebellar atrophy associated with Dilantin may not be an acceptable alternative.

Dilantin Background

Dilantin has a long history of use as an anti-epileptic drug. It was originally invented in 1908 to prevent convulsions associated with electroshock therapy. Phenytoin’s anti-seizure properties were first noticed in the 1930s.

Soon after that, Parke, Davis & Co. was producing phenytoin capsules that were ready to market. The application of Dilantin as a treatment for epilepsy was considered a breakthrough discovery then, and it inspired the development of several new anticonvulsants over the next several years.

Today, Dilantin is one of the most widely-used anti-epileptic drugs in the world. While it’s not always the first choice for ongoing therapy, it can be a first-line treatment for emergency cases of seizure or status epilepticus.