Keppra Does Not Cause Pseudobulbar Affect
Based on FDA labeling and available clinical evidence, levetiracetam (Keppra) is not known to cause pseudobulbar affect (PBA). The extensive adverse event profile documented in clinical trials and post-marketing surveillance does not include PBA as a recognized side effect.
Evidence from FDA Drug Labeling
The FDA-approved prescribing information for Keppra lists comprehensive adverse events from controlled clinical trials involving over 1,200 patients 1. The documented psychiatric and behavioral adverse effects include:
- Mood and behavioral changes: aggression, agitation, anger, anxiety, apathy, mood swings, depression, hostility, and irritability
- Psychiatric symptoms: hallucinations, delusions, unusual behavior, psychosis
- Emotional effects: emotional lability, personality disorder
Notably, pseudobulbar affect is not mentioned anywhere in the FDA labeling despite extensive documentation of neuropsychiatric side effects 1.
Clinical Trial Safety Data
Large-scale systematic reviews of levetiracetam's safety profile have catalogued adverse effects in detail. A comprehensive 2014 analysis examined all adverse effects from controlled trials and found the most common issues were somnolence, headache, asthenia, dizziness, infection, and various behavioral changes 2. PBA was not identified as an adverse effect in this systematic evaluation.
Similarly, a 2001 systematic safety review of 3,347 patients exposed to levetiracetam during clinical development documented predominantly somnolence, asthenia, dizziness, and behavioral effects, but made no mention of pathological laughing or crying consistent with PBA 3.
Important Distinction: Emotional Lability vs. Pseudobulbar Affect
While Keppra can cause emotional lability (reported in 2-6% of patients) 1, this is distinct from pseudobulbar affect:
- Emotional lability: mood swings, irritability, and emotional instability that are contextually appropriate but exaggerated
- Pseudobulbar affect: involuntary, inappropriate outbursts of laughing or crying that are disconnected from the patient's actual emotional state and associated with specific neurological pathologies 4
Clinical Implications
If a patient on Keppra develops symptoms resembling PBA:
- Investigate underlying neurological conditions that independently cause PBA (stroke, ALS, multiple sclerosis, traumatic brain injury, dementia)
- Consider whether the patient's epilepsy itself or structural brain lesions might be contributing
- Evaluate for emotional lability versus true PBA using validated instruments like the Center for Neurologic Study Lability Scale (CNS-LS) 5
- Do not automatically attribute PBA symptoms to levetiracetam without ruling out other causes
The behavioral side effects of Keppra are well-documented and common (hostility, aggression, mood changes), but these do not constitute pseudobulbar affect 1, 6, 7.