The most frequent and serious adverse effects of beta blockers is directly related to its ability to block beta receptors. The most serious adverse effects are heart failure, heart block, and bronchspasm. Other more minor side-effects include fatigue and coldness of extremities. Reactions tend to be more severe after intravenous injection as opposed to oral administration.
Include bradycardia and hypotension. Congestive heart failure or heart block, this can be precipitated in patients with previously underlying cardiac disorder. Abrupt withdrawal of beta blockers may exacerbate angina and may lead to sudden death.
This may be precipitated in some susceptible patients due to blockade of beta 2 receptors in the brochial smooth muscle. Pneumonitis, pulmonary fibrosis, and pleurisy have also been reported.
These include depression, hallucinations, confusion and sleep disturbances. Convulsions and coma have been reported following beta blocker overdose. Beta blockers with a high lipid solubility are more likely to cause these effects. Atenolol is hydrophilic.
Including paraesthesia, prehipheral neuropathy and myopathies have been reported.
Nausea and vomiting, diarrhoea, constipation, and abdominal cramping.
Skin rash, pruritus, and reversible alopecia.
Decreased tear production, blurred vision and soreness
Nonthrombocytopenic purpura, thrombocytopenia, and rarely agranulocytosis. Transient eosinophilia can occur
These include metabolic changes that affect glucose control and cholesterol concentrations. Also lupus-like syndrome, male impotence, sclerosing peritonitis, and retroperitoneal fibrosis.
Many overdose cases concerning beta blockers are uneventful, but some patients do develop severe and occasionally fatal cardiovascular depression. Effects can include bradycardia, cardiac conduction block, hypotension, cardiac failure, and cardiogenic shock. Convulsions, coma, respirtory depression, and bronchoconstriction can also occur, although infrequently.
Most reports of serious toxic reactions following beta blocker overdose concern beta blockers with significant membrane-stabilising activity, such as propanolol or oxprenolol. Overdose of beta blockers with intrinsic sympathomimetic activity may give tachycardia and hypertension. Overdose of sotalol, a beta blocker with class II and class III anti-arrhythmic properties usually gives rise to ventricular tachyarrhythmia
Gastric lavage with charcoal for patients who have recently ingested the beta blocker. When indicated additional measures can be instituted to counter hypotension. Mild hypotension may respond to fluid administration; if hypotension continues glucagon or sympathomimetic agents may be required. Bradycardia may be treated with atropine, sympathomimetic agents or a pacemaker. If anti-arrhythmic agents are required, lignocaine or phenytoin are preferred.
