Most adverse reactions have been mild and transient and are typical of beta-adrenergic blocking agents, eg, bradycardia, fatigue, dyspnea, and lethargy. Withdrawal of therapy in U.S. and European controlled clinical trials has been necessary in about 3.5% of patients, principally because of bradycardia, fatigue, dizziness, headache, and impotence.
Frequency estimates of adverse events were derived from controlled studies in which adverse reactions were volunteered and elicited in U.S. studies and volunteered and/or elicited in European studies.
In the U.S., the placebo-controlled hypertension studies lasted for 4 weeks, while the active-controlled hypertension studies had a 22- to 24-week double-blind phase. The following doses were studied: betaxolol—5, 10, 20, and 40 mg once daily; atenolol—25, 50, and 100 mg once daily; and propranolol—40, 80, and 160 mg b.i.d.
Betaxolol, like other beta-blockers, has been associated with the development of antinuclear antibodies (ANA) (e.g., lupus erythematosus). In controlled clinical studies, conversion of ANA from negative to positive occurred in 5.3% of the patients treated with betaxolol, 6.3% of the patients treated with atenolol, 4.9% of the patients treated with propranolol, and 3.2% of the patients treated with placebo.
Betaxolol adverse events reported with a 2% or greater frequency, and selected events with lower frequency, in U.S. controlled studies are:
Of the above adverse reactions associated with the use of betaxolol, only bradycardia was clearly dose related, but there was a suggestion of dose relatedness for fatigue, lethargy, and dyspepsia.
In Europe, the placebo-controlled study lasted for 4 weeks, while the comparative studies had a 4-52-week double-blind phase. The following doses were studied: betaxolol 20 and 40 mg once daily and atenolol 100 mg once daily.
From European controlled hypertension clinical trials, the following adverse events reported by 2% or more patients and selected events with lower frequency are presented:
The only adverse event whose frequency clearly rose with increasing dose was bradycardia. Elderly patients were especially susceptible to bradycardia, which in some cases responded to dose-reduction (see
Precautions).
The following selected (potentially important) adverse events have been reported at an incidence of less than 2% in U.S. controlled and open, long-term clinical studies, European controlled clinical trials, or in marketing experience. It is not known whether a causal relationship exists between betaxolol and these events; they are listed to alert the physician to a possible relationship:
Autonomic: flushing, salivation, sweating.
Body as a whole: allergy, fever, malaise, pain, rigors.
Cardiovascular: angina pectoris, arrhythmia, atrioventricular block, heart failure, hypertension, hypotension, myocardial infarction, thrombosis, syncope.
Central and peripheral nervous system: ataxia, neuralgia, neuropathy, numbness, speech disorder, stupor, tremor, twitching.
Gastrointestinal: anorexia, constipation, dry mouth, increased appetite, mouth ulceration, rectal disorders, vomiting, dysphagia.
Hearing and Vestibular: earache, labyrinth disorders, tinnitus, deafness.
Hematologic: anemia, leucocytosis, lymphadenopathy, purpura, thrombocytopenia.
Liver and biliary: increased AST, increased ALT.
Metabolic and nutritional: acidosis, diabetes, hypercholesterolemia, hyperglycemia, hyperkalemia, hyperlipemia, hyperuricemia, hypokalemia, weight gain, weight loss, thirst, increased LDH.
Musculoskeletal: arthropathy, neck pain, muscle cramps, tendonitis.
Psychiatric: abnormal thinking, amnesia, impaired concentration, confusion, emotional lability, hallucinations, decreased libido.
Reproductive disorders: Female: breast pain, breast fibroadenosis, menstrual disorder; Male: Peyronie's disease, prostatitis.
Respiratory: bronchitis, bronchospasm, cough, epistaxis, flu, pneumonia, sinusitis.
Skin: alopecia, eczema, erythematous rash, hypertrichosis, pruritus, skin disorders.
Special senses: abnormal taste, taste loss.
Urinary system: cystitis, dysuria, micturition disorder, oliguria, proteinuria, abnormal renal function, renal pain.
Vascular: cerebrovascular disorder, intermittent claudication, leg cramps, peripheral ischemia, thrombophlebitis.
Vision: abnormal lacrimation, abnormal vision, blepharitis, ocular hemorrhage, conjunctivitis, dry eyes, iritis, cataract, scotoma.