Common side effects are somnolence, dizziness, confusion, anterograde amnesia or memory impairment, feeling of drunkenness, euphoria, nightmares, agitation, anxiety or nervousness, hostility, depression, decreased libido, libido disorder, coordination abnormality, headache, hypotonia, tremor, muscle spasms, paresthesia, and speech disorder, palpitations, dysgeusia (bitter taste), dry mouth, coated tongue, bad breath, nausea, vomiting, diarrhea, constipation, anorexia or increased appetite.