From the digestive system: abdominal pain, nausea, vomiting, diarrhea.
From the nervous system: confusion, memory impairment, hallucinations, dizziness, anxiety,"nightmarish" dreams, severe headache, daytime sleepiness; disorders of coordination of movements, muscle weakness, diplopia, anterograde amnesia.
Allergic reactions: skin rash, itching.
Other: drug dependence (with prolonged use).