Pruritus, rashes, urticaria; dizziness, headache, tremors, convulsion, ataxia, confusion, hallucinations, insomnia, nervousness, paresthesia, involuntary muscle contraction, vertigo; occasionally HTN, hypotension, palpitation, tachycardia, arrhythmia; abdominal pain, constipation, diarrhea, dyspepsia, flatulence, dry mouth, vomiting; occasionally dyspnea.