Can Keppra Cause Drowsiness?
Yes, Keppra (levetiracetam) commonly causes drowsiness and somnolence, which is one of its most frequently reported adverse effects across all patient populations.
Incidence of Drowsiness
Somnolence occurs in approximately 15% of adult patients taking levetiracetam for partial onset seizures, compared to 8% in placebo-treated patients 1. This makes drowsiness one of the most prominent adverse effects alongside asthenia and dizziness 2.
- In pediatric patients (ages 4-16 years), somnolence was reported in 23% of levetiracetam-treated patients versus 11% in placebo-treated patients 1
- For patients with myoclonic seizures, somnolence occurred in 12% of levetiracetam-treated patients compared to 2% in placebo 1
Time Course and Clinical Characteristics
Drowsiness typically appears predominantly during the first 4 weeks of treatment with levetiracetam 1. This temporal pattern is important for counseling patients about what to expect.
- The sedative effects are generally dose-related, with higher doses (2000-3000 mg/day) showing increased incidence 3
- Most cases are mild to moderate in intensity 1
- In overdose situations, drowsiness is the primary symptom, with cases of somnolence, depressed level of consciousness, and even coma reported in postmarketing surveillance 1
Comparative Context with Other Antiepileptic Drugs
Levetiracetam's drowsiness profile is consistent with other antiepileptic medications but may be less pronounced than some alternatives:
- Gabapentin causes somnolence, dizziness, ataxia, and fatigue 4
- Carbamazepine commonly causes drowsiness and dizziness 4
- Dihydroergotamine (used for migraines) lists drowsiness among its adverse effects 4
Clinical Management Considerations
Patients should be explicitly advised not to drive, operate machinery, or engage in hazardous activities until they have gained sufficient experience on levetiracetam to gauge whether it adversely affects their performance 1.
Important counseling points:
- The drowsiness effect may diminish after the first month of therapy 1
- Combining levetiracetam with benzodiazepines increases the risk of oversedation 4
- Dose titration starting at lower doses may help minimize sedative effects 4
Additional Sedation-Related Adverse Effects
Beyond simple drowsiness, levetiracetam can cause related symptoms:
- Fatigue and asthenia (weakness) occur in 15% of patients 1
- Dizziness affects 9% of patients 1
- Vertigo occurs in 3% of patients 1
Special Populations
In brivaracetam (a related compound), drowsiness was the most common adverse effect at 17.3% in pediatric patients, suggesting this is a class effect of these medications 5. The sedative profile appears consistent across age groups, though pediatric patients may experience slightly higher rates 1.