Hypersensitivity; asthenia, fatigue, hot flushes; dizziness, headache, tremor; abdominal pain, constipation, diarrhea, dyspepsia, flatulence, dry mouth, nausea, vomiting; anorexia, anxiety, confusion, euphoria, insomnia, nervousness, somnolence; pruritus, rash, increased sweating; urticaria; abnormal hepatic function, decrease wt, tinnitus, abnormal vision, shivers. Occasionally, chest pain, rigors, syncope, w/drawal syndrome; HTN, aggravated HTN, hypotension, arrhythmia, palpitation, tachycardia; ataxia, convulsion, hypertonia, migraine, aggravated migraine, involuntary muscle contractions, paresthesia, stupor, vertigo; dysphagia, melena, tongue edema; amnesia, depersonalization, depression, drug abuse & dependence, emotional instability, hallucination, impotence, nightmare, abnormal thinking; anemia; dyspnea; albuminuria, micturition disorder, oliguria, urinary retention.