Most adverse effects have been mild and transient and have rarely required withdrawal of therapy.
Cardiovascular—Bradycardia with heart rates of less than 60 beats per minute occurs commonly, and heart rates below 40 beats per minute and/or symptomatic bradycardia were seen in about 2 of 100 patients. Symptoms of peripheral vascular insufficiency, usually of the Raynaud type, have occurred in approximately 2 of 100 patients. Cardiac failure, hypotension, and rhythm/conduction disturbances have each occurred in about 1 of 100 patients. Single instances of first degree and third degree heart block have been reported; intensification of AV block is a known effect of beta-blockers (see also CONTRAINDICATIONS, WARNINGS, and PRECAUTIONS).
Central Nervous System—Dizziness or fatigue has been reported in approximately 2 of 100 patients; paresthesias, sedation, and change in behavior have each been reported in approximately 6 of 1000 patients.
Gastrointestinal—Nausea, diarrhea, abdominal discomfort, constipation, vomiting, indigestion, anorexia, bloating, and flatulence have been reported in 1 to 5 of 1000 patients.
Miscellaneous—Each of the following has been reported in 1 to 5 of 1000 patients: rash; pruritus; headache; dry mouth, eyes, or skin; impotence or decreased libido; facial swelling; weight gain; slurred speech; cough; nasal stuffiness; sweating; tinnitus; blurred vision. Reversible alopecia has been reported infrequently.
The following adverse reactions have been reported in patients taking nadolol and/or other beta-adrenergic blocking agents, but no causal relationship to nadolol has been established.
Central Nervous System—Reversible mental depression progressing to catatonia; visual disturbances; hallucinations; an acute reversible syndrome characterized by disorientation for time and place, short-term memory loss, emotional lability with slightly clouded sensorium, and decreased performance on neuropsychometrics.
Gastrointestinal—Mesenteric arterial thrombosis; ischemic colitis; elevated liver enzymes.
Hematologic—Agranulocytosis; thrombocytopenic or nonthrombocytopenic purpura.
Allergic—Fever combined with aching and sore throat; laryngospasm; respiratory distress.
Miscellaneous—Pemphigoid rash; hypertensive reaction in patients with pheochromocytoma; sleep disturbances; Peyronie's disease.
The oculomucocutaneous syndrome associated with the beta-blocker practolol has not been reported with nadolol.
Gastrointestinal—Nausea, vomiting, cramping and anorexia are not uncommon; diarrhea, constipation, gastric irritation, abdominal bloating, jaundice (intrahepatic cholestatic jaundice), hepatitis, and sialadenitis occasionally occur; and pancreatitis has been reported.
Central Nervous System—Dizziness, vertigo, paresthesia, headache, and xanthopsia occasionally occur.
Hematologic—Leukopenia, agranulocytosis, thrombocytopenia, hemolytic anemia, and aplastic anemia have been reported.
Dermatologic-Hypersensitivity—Purpura, exfoliative dermatitis, pruritus, ecchymosis, urticaria, necrotizing angiitis (vasculitis, cutaneous vasculitis), respiratory distress including pneumonitis, fever, and anaphylactic reactions occasionally occur; photosensitivity and rash have been reported.
Cardiovascular—Orthostatic hypotension may occur and may be potentiated by coadministration with certain other drugs (e.g., alcohol, barbiturates, narcotics, other antihypertensive medications, etc.; see PRECAUTIONS, Drug Interactions).
Other—Muscle spasm, weakness, or restlessness is not uncommon; hyperglycemia, glycosuria, metabolic acidosis in diabetic patients, hyperuricemia, allergic glomerulonephritis, and transient blurred vision occasionally occur.
Whenever adverse reactions are moderate or severe, thiazide dosage should be reduced or therapy withdrawn.