Antiepileptic Drug Selection: Key Considerations for Seniors
Treating seizures in older adults presents unique challenges due to age-related changes in metabolism, increased risk of drug interactions from polypharmacy, and heightened sensitivity to side effects. The primary goal is achieving optimal seizure control while maintaining the best possible quality of life. This often means favoring newer antiepileptic drugs (AEDs) with more favorable side effect profiles and fewer drug-drug interactions, though some older AEDs remain viable options.
Newer Antiepileptic Drugs (AEDs)
Newer-generation AEDs are frequently preferred as first-line treatment for seizures in the elderly due to better tolerability and fewer interactions with other medications commonly taken by seniors.
- Levetiracetam (Keppra): This is often a top choice for elderly patients because it has a highly favorable pharmacokinetic profile—it does not bind significantly to proteins and is not metabolized by the liver, which reduces the risk of drug interactions. Careful consideration is needed for patients with kidney problems. Side effects can include somnolence, dizziness, and behavioral changes, such as irritability, in a small percentage of patients.
- Lacosamide (Vimpat): Well-tolerated in older adults, lacosamide is used for focal (partial-onset) seizures. While its safety profile is generally favorable, clinicians should exercise caution with patients who have heart problems due to a potential risk of cardiac conduction abnormalities. Careful adjustment of administration is recommended to minimize side effects like dizziness and unsteadiness.
- Lamotrigine (Lamictal): This drug is effective for both focal and generalized seizures and is generally well-tolerated. The most notable side effect is a skin rash, which can be minimized by a slow introduction schedule. Lamotrigine is an option for older adults with severe kidney disease as it is largely metabolized by the liver.
- Gabapentin (Neurontin): Praised for its favorable pharmacokinetic properties and lack of liver metabolism, gabapentin is a good candidate for older adults, particularly those with kidney dysfunction. It is well-absorbed and eliminated unchanged by the kidneys. Side effects can include drowsiness and dizziness, which are important to monitor for due to increased fall risk in seniors.
- Oxcarbazepine (Trileptal): Similar in structure to carbamazepine, oxcarbazepine has fewer drug interactions and a better side effect profile. However, it can cause hyponatremia (low sodium levels), which is a significant concern for older adults who may already be on diuretics.
Traditional Antiepileptic Drugs (AEDs)
Older AEDs are less commonly used as first-line options in the elderly but may be used successfully, especially if the patient is already on the medication or for cost considerations. They often come with a higher risk of side effects and more significant drug interactions.
- Carbamazepine (Tegretol): An older drug that is effective for focal seizures, but its use in the elderly is limited by side effects like hyponatremia and potential cardiac conduction issues. It also has numerous drug interactions, making it a poor choice for patients on multiple medications.
- Phenytoin (Dilantin): Another older and effective option, phenytoin is often avoided in the elderly due to its complex and saturable metabolism, which can lead to unpredictable drug levels. It also has many potential drug interactions and side effects, including cognitive impairment.
- Valproic Acid (Depakote): Effective for both focal and generalized seizures, valproic acid can cause side effects such as weight gain and tremor. It is also associated with a higher risk of serious liver and hematologic side effects, though newer AEDs appear safer.
Medication Management and Monitoring for Seniors
Due to reduced drug clearance and increased sensitivity, older adults often require careful consideration of medication levels and slower adjustments than younger patients. The approach of careful initiation and gradual adjustments is important in this population. Close monitoring for adverse effects and drug-drug interactions is essential throughout treatment. Regular assessments may be necessary for some medications to ensure appropriate levels are maintained safely.
Managing Side Effects in the Elderly
Older adults are more susceptible to certain AED side effects, which can have more severe consequences. Monitoring and management are crucial.
- Cognitive Issues: Sedation, confusion, and memory impairment are common side effects of many AEDs, especially older ones like phenobarbital. This can be particularly problematic for seniors who may have pre-existing cognitive deficits.
- Increased Fall Risk: Dizziness, unsteadiness, and drowsiness from AEDs can increase the risk of falls, a major cause of morbidity and mortality in the elderly. Newer drugs like lacosamide and levetiracetam can cause these side effects, especially during initial introduction.
- Hyponatremia: Oxcarbazepine and carbamazepine can cause low sodium levels, a risk that increases with age and concurrent diuretic use.
Comparison of AEDs for Elderly Seizure Patients
| Feature | Levetiracetam | Lacosamide | Lamotrigine | Carbamazepine | Phenytoin |
|---|---|---|---|---|---|
| Efficacy | Broad spectrum | Narrow spectrum (focal) | Broad spectrum | Narrow spectrum (focal) | Narrow spectrum (focal) |
| Drug Interactions | Very low | Very low | Low | High | High |
| Metabolism | Renal | Hepatic/Renal | Hepatic | Hepatic | Hepatic |
| Key Side Effects (Elderly) | Dizziness, somnolence, mood changes | Dizziness, unsteadiness, PR interval prolongation | Rash, dizziness, headache | Hyponatremia, dizziness, cardiac effects | Cognitive impairment, cardiac effects, liver issues |
| Adjustment | Can be faster, but slow with renal issues | Careful adjustment recommended | Very slow adjustment recommended | Requires careful adjustment | Complex, requires careful monitoring |
| Risk of Falls | Moderate | Moderate | Low to moderate | Moderate | High |
Conclusion
While a variety of antiepileptic drugs are available for treating seizures in the elderly, careful consideration of the patient's overall health, cognitive status, and other medications is critical. Newer agents such as levetiracetam, lacosamide, and lamotrigine are often favored for their more favorable side effect profiles and lower potential for drug-drug interactions. Slower adjustment schedules and vigilant monitoring are essential for minimizing adverse effects and ensuring patient safety. The decision on the best treatment should always be made in consultation with a qualified healthcare professional, who can weigh the individual risks and benefits of each medication.
For more in-depth information on seizures and epilepsy, consult the Epilepsy Foundation.
