The study, “Antiepileptic Drugs and Accumulation of Hospital Days Among Persons With Alzheimer’s Disease,” was published in The Journal of Post-Acute and Long-Term Care Medicine.

Anti-epileptic drugs (AEDs) are commonly used by older patients with Alzheimer’s disease. In addition to their primary indication — epilepsy — AEDs are used to manage other conditions, including bipolar and mood disorders, migraines, and even symptoms of dementia. However, because AEDs have been previously associated with an increased risk of strokes, falls, drug-drug interactions, and treatment-related adverse events, physicians should carefully consider the prescription of these medications.

In fact, one-third of AED-related adverse events result in hospitalization, highlighting the need for better risk assessment of AED administration in elderly patients with Alzheimer’s disease.

A group of Finnish researchers compared the number of days spent in the hospital between Alzheimer’s disease patients, enrolled in the Medication use and Alzheimer’s disease (MEDALZ) study, who took AEDs versus those who did not. Individuals were followed until discontinuation of AEDs, death, or upon two years of follow-up, whichever occurred first.

The MEDALZ study includes Finnish patients newly diagnosed with Alzheimer’s disease between 2005 and 2011,  and contains patients’ clinical data, including prescribed medications, complementary diagnoses, hospitalizations, and medical procedures.

The study included 4,432 patients who had begun AEDs for the first time after an Alzheimer’s diagnosis and 4,432 matched controls who were patients matched for age, gender, and time since Alzheimer’s diagnosis who had never taken an AED. Individuals with epilepsy were excluded from the study.

For each group, women represented 66.3% of participants, and the median age of the patients was 80 years old. Use of psychotropics and opioids, as well as other medications, was more frequent among those taking AEDs.

The results showed that, during the two-year period, those on AEDs were hospitalized for a longer period (43.7 days) than those not on AEDs (32.2 days). The number of accumulated days in the hospital was 31% higher among AED users than control patients. The same trend was seen for general and specialized health care.

The most common reason for hospitalization was dementia. Patients on AEDs were more likely to spend more days in the hospital than control patients due to infectious diseases, cognitive, behavioral (excluding dementia), and neurological disturbances (excluding Alzheimer’s), and respiratory and musculoskeletal diseases. They also had a higher rate of abnormal clinical and laboratory parameters.

Pregabalin (marketed under the brand name Lyrica, among others) was the most commonly used (50.9%) AED, followed by valproic acid (25.0%, marketed as Depakote), gabapentin (5.7%, sold as Neurontin), and carbamazepine (5.5%, brand name Tegretol).

Pregabalin and gabapentin were associated with fewer hospitalization days than valproic acid. In addition, there were more deaths among those who took AEDs other than pregabalin and gabapentin.

Researchers noted, however, that a major limitation in their analysis was the lack of records on therapy use by patients staying at public nursing homes or in hospital care. As a result, they may have missed the most severe Alzheimer’s disease cases.

These findings suggest that Alzheimer’s patients taking AEDs are at a higher risk of longer hospitalizations than those who are not, both in general and specialized health.

“As clinicians, we need to carefully consider benefits and adverse effects as well as proper indications before prescribing antiepileptics to persons with Alzheimer’s disease,” the researchers concluded.