Dilantin, also known as phenytoin, is one of the oldest and most frequently prescribed anti-convulsants used to treat seizures.

But even with its long track record, Dilantin is not without its side effects, some of which can be fairly serious.

Published research and case studies reveal cases in which Dilantin patients developed cerebellar ataxia, a set of movement-related symptoms that can result from focal cerebral atrophy in a part of the brain that controls voluntary movement.

Cases of Dilantin Cerebellar Ataxia in Medical Literature

In one study published in the last few years, researchers studied 25 epilepsy patients who had been treated with phenytoin in the long-term in order to gain more knowlege about Dilantin cerebellar ataxia.

The mean duration of the patients’ phenytoin treatment was 21 years.

Out of this group, 68 percent of the patients reported poor balance, and 52 percent showed clinical evidence of ataxia on exam.

Among patients with ataxia whose imaging studies were available, cerebellar atrophy was visible in 50 percent of those patients’ imaging.

The report notes that Dilantin cerebellar ataxia is one of the reasons for which use of Dilantin is on the decline.

A few published case studies document the experiences of individual patients who suffered from what doctors say was Dilantin cerebellar ataxia.

One such study published details a case of cerebellar ataxia in a 16-year-old boy.

The boy had a 10-year history of seizures, treated for most of that time with phenytoin. After being hospitalized for fever and weakness, he began to complain of difficulty walking. A central nervous system examination revealed cerebellar signs, including ataxia.

Although previous MRI scans of his brain had shown no abnormality, a new scan revealed visible cerebellar atrophy.

A causality assessment using the Naranjo scale showed that his condition was probably related to his long-term treatment with phenytoin. His doctors report he began to recover steadily after discontinuing phenytoin.

Ataxia Symptoms

The most characteristic symptoms of Dilantin cerebellar ataxia are movement-related.

Patients typically have trouble walking, keeping their balance, or maintaining upright posture. Some patients report having to concentrate on their movements in ways they had not previously had to.

Smaller, finer movements can also be affected. Some patients have difficulty with writing, typing, preparing food or putting on clothes. Speech can become slow, slurred or indistinct, and trouble with swallowing may create a choking hazard.

Other symptoms can follow from these movement problems. Since ataxia makes the patient’s movement less efficient and coordinated, it may require them to expend more energy. This expenditure can cause some patients to develop unexpected fatigue.

The effects of cerebellar ataxia are not limited to physical movement. The condition affects a significant part of the brain, and because of that it can cause emotional and cognitive problems too.

Patients report suffering from cognitive distortions like difficulty with making plans or decisions, recalling newly learned information, or keeping their thoughts in order.

Cerebellar degeneration can also lead to an increased incidence of personality and mood symptoms like anxiety, depression and irritability.