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Ilo Leppik, MD
At the 68th Annual Meeting of the American Academy of Neurology, Dr. Leppik discusses epilepsy in the elderly and an approach to selecting...
WASHINGTON, DC—When initiating antiseizure therapy for elderly patients with epilepsy, drug interactions and side effects, especially impaired cognition and falls, are important treatment considerations, according to an overview given at the 71st Annual Meeting of the American Epilepsy Society.
In addition, neurologists should take into account comorbidities and concomitant medications that could be relevant in the future—similar to considering the possibility of pregnancy when treating a patient of childbearing potential, said Ilo Leppik, MD, Professor of Neurology and Pharmacy at the University of Minnesota in Minneapolis. An elderly patient with poststroke seizures, for instance, may not be on warfarin at an initial visit. “But they might be … the next time you see them,” he said. “In the next six months, what could this person have in terms of comorbidities?”
Ilo Leppik, MD
Interactions and Side Effects
“In general, most antiseizure drugs are effective for epilepsy encountered in the elderly,” Dr. Leppik said. “Drug interactions and cognitive and behavioral side effects are key.”
Research indicates that a drug’s side effect profile, rather than its efficacy, determines how long patients stay on a medication. Dr. Leppik tries to see elderly patients about a month after starting treatment and asks family members to report cognitive or behavioral changes.
“My preferred approach is not to use drugs that are strong enzyme inducers because of the issues with drug–drug interactions,” Dr. Leppik said. Blood levels of simvastatin, for example, are markedly lower in patients who receive carbamazepine and are likely to be so with other inducing antiseizure drugs.
Hyponatremia may be a concern. Xiaoming Dong, MD, Dr. Leppik, and colleagues found that oxcarbazepine is a significant cause of hyponatremia in people over age 40, and the risk is greater in people over age 65, he said.
In addition, many older patients have cognitive issues, and antiseizure drugs (eg, topiramate, zonisamide, valproic acid, phenobarbital, and phenytoin) may cause cognitive side effects. One clinical question that neurologists may encounter is whether to treat a patient with end-stage Alzheimer’s disease who has a single convulsion. Families may want to initiate antiseizure treatment. “But my experience is that if you start them on any of our antiseizure medications, [these patients] are much more sensitive to side effects,” Dr. Leppik said. “I have seen them deteriorate cognitively once they are started on an antiseizure medication.”
The risk of falls increases with age, and studies have found that higher levels of antiseizure drugs are associated with falls and fractures. Falls may be related to the adverse effects of antiseizure drugs, such as dizziness or ataxia. Prescribing an antiseizure drug with a long half-life once daily at bedtime may help to avoid daytime imbalance, Dr. Leppik said.
Therapeutic Drug Monitoring
Monitoring serum concentrations of antiseizure drugs may help guide patient management. When a therapeutic response has been reached, measuring the drug level can provide a target benchmark. When treatment is not working, in most cases it is because blood levels are not at the target level, Dr. Leppik added. Monitoring also may be useful when a drug is added or removed, or when there are concerns about toxicity or compliance.
“Most breakthrough seizures are due to the fact that there is some noncompliance,” Dr. Leppik said. Among elderly patients with impaired memory, the likelihood of missed medications may be greater.
—Jake Remaly
Suggested Reading
Dong X, Leppik IE, White J, Rarick J. Hyponatremia from oxcarbazepine and carbamazepine. Neurology. 2005;65(12):1976-1978.
Leppik IE, Birnbaum AK. Epilepsy in the elderly. Ann N Y Acad Sci. 2010;1184:208-224.
Leppik IE, Walczak TS, Birnbaum AK. Challenges ofepilepsy in elderly people. Lancet. 2012;380(9848):1128-1130.
Patsalos PN, Berry DJ, Bourgeois BF, et al. Antiepileptic drugs--best practice guidelines for therapeutic drug monitoring: a position paper by the subcommission on therapeutic drug monitoring, ILAE Commission on Therapeutic Strategies. Epilepsia. 2008;49(7):1239-1276.
