The most common reactions encountered are drowsiness, nausea/vomiting, headache and dry mouth. Other reactions reported include the following:
Behavioral:
Drowsiness, fatigue, lethargy, retardation, lightheadedness, dizziness, difficulty in concentration, confusion, impaired memory, disorientation, excitement, agitation, anxiety, tension, nervousness, restlessness, insomnia, nightmares, anger, hostility and, rarely, hypomania, visual distortions, hallucinations, delusions and paranoia.
Neurologic:
Tremor, headache, ataxia, akathisia, muscle stiffness, slurred speech, retarded speech, vertigo, tinnitus, tingling of extremities, paresthesia, weakness, grand mal seizures (see Precautions), and, rarely impaired speech, muscle twitching, numbness, dystonia and involuntary movements.
Autonomic:
Dry mouth, blurred vision, diplopia, miosis, nasal congestion, constipation, sweating, urinary retention, increased urinary frequency and incontinence.
Cardiovascular:
Orthostatic hypotension, hypertension, tachycardia, palpitations, shortness of breath, apnea, syncope, arrhythmias, prolonged P-R interval, atrial fibrillation, bradycardia, ventricular ectopic activity (including ventricular tachycardia), myocardial infarction and cardiac arrest.
Gastrointestinal:
Nausea, vomiting, diarrhea, gastrointestinal discomfort, anorexia, increased appetite.
Endocrine:
Priapism (see Warnings), decrease and, more rarely, increase in libido, weight gain and loss, and rarely, menstrual irregularities, retrograde ejaculation and inhibition of ejaculation.
Allergic or toxic:
Skin rash, itching, edema, and, rarely, hemolytic anemia, methemoglobinemia, liver enzyme alterations, obstructive jaundice, leukocytoblastic vasculitis, purpuric maculopapular eruptions, photosensitivity and fever.
Miscellaneous:
Aching joints and muscles, peculiar taste, hypersalivation, chest pain, hematuria, red, tired and itchy eyes.
