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.
Cardiovascular Effects 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.