Patients who use Dilantin to get relief from some epilepsy symptoms may be putting themselves at risk for cerebellar ataxia, a condition that can degrade their coordination and physical movement.

What Is Cerebellar Ataxia?

Cerebellar ataxia is a set of movement-related symptoms that may appear following damage to the cerebellum, a part of the brain that’s largely responsible for controlling voluntary muscle movement.

The cerebellum is a pair of ping-pong ball sized masses of tissue at the base of the rear of the brain.

Damage, loss of nerve cells, or focal cerebral atrophy within this part of the brain can affect a person’s ability to control both large and small movements.

A characteristic symptom of cerebellar ataxia is difficulty walking. Patients may not be able to maintain balance or posture as well as they used to, and they may have difficulty standing or walking on unsteady surfaces like escalators or elevators.

Smaller movements like writing, eating or buttoning a shirt may also become more difficult. The condition can also affect speech, swallowing and eye movements.

There are many possible types of causes of cerebellar damage that can lead to ataxia. The condition can result from diseases, head injuries or toxic reactions to certain drugs.

Toxic levels of alcohol and other drugs can lead to cerebellar symptoms. Barbiturates like Phenobarbital and sedatives like benzodiazepines can also lead to these types of conditions.

There’s also evidence that ataxia can develop in epilepsy patients who treat their condition with long-term use of Dilantin.

Dilantin, or phenytoin, has a long history. Originally developed over a hundred years ago to treat the convulsions associated with electroshock therapy, it was later discovered to have anti-seizure properties.

By 1940, researchers believed Dilantin would prove to be the first in a whole new class of anti-epilepsy drugs.

Other anti-epilepsy medications have come along since Dilantin began to be used. It’s now generally considered to be a second-line treatment for most uses.

Still, Dilantin remains one of the most frequently prescribed drugs in the world.

Researchers have been aware for years that some epilepsy patients develop cerebellar ataxia while taking Dilantin.

Earlier research could not conclusively establish whether these cases resulted from Dilantin or from the epilepsy itself.

More recent research suggests these cases of cerebellar ataxia are related to Dilantin.

Researchers Link Dilantin to Cerebellar Damage

For example, in one study published in the journal Seizure in July 2003, researchers looked at imaging studies from 56 epilepsy patients all of whom had taken Dilantin (referenced in the study by its generic name phenytoin) for more than two months.

The researchers found signs of cerebellar ataxia (atrophy) in 20 of these patients. They found no association between that condition and frequent generalized seizures. However, after a full analysis, the only factor that correlated with cerebellar ataxia was the length of time the patient had been taking Dilantin.

The researchers concluded that cerebellar ataxia is frequently associated with long-term Dilantin treatment. They noted that although the duration of the patient’s epilepsy may also be a factor, it’s clearly less important than the amount of time the patient had been exposed to Dilantin.