The following adverse reactions have been observed but there are not enough data to support an estimate of their frequency. Consequently the reactions are categorized by organ system and are listed in decreasing order of severity and not frequency.
Digestive: Diarrhea, which may be severe at times and necessitate discontinuance of medication; vomiting; nausea; increased bowel movements, dry mouth; parotid tenderness.
Cardiovascular: Chest pains (angina); bradycardia; a tendency toward fluid retention and edema with occasional development of congestive heart failure.
Respiratory: Dyspnea; asthma in susceptible individuals; nasal congestion.
Neurologic: Syncope resulting from either postural or exertional hypotension; dizziness; blurred vision; muscle tremor; ptosis of the lids; mental depression; chest paresthesias; weakness; lassitude; fatigue.
Genitourinary: Rise in BUN; urinary incontinence; inhibition of ejaculation; nocturia.
Metabolic: Weight gain
Skin and Appendages: Dermatitis; scalp hair loss.
Although a causal relationship has not been established, a few instances of blood dyscrasias (anemia, thrombocytopenia, and leukopenia) and of priapism or impotence have been reported.