Beta-adrenoceptor antagonists hypotension

Although atenolol, a hydrophihc cardioselective beta-adrenoceptor antagonist with no partial agonist activity, is generally regarded as one of the safest beta-blockers, severe adverse effects are occasionally reported. These include profound hypotension after a single oral dose (1), organic brain syndrome (2), cholestasis (3), and cutaneous vascuhtis (4). 

The hypotensive effects of halothane and barbiturates can be exaggerated by beta-adrenoceptor antagonists. However, they are not contraindicated in anesthesia, provided the anesthetist is aware of what the patient is taking. 

Drug adulteration Adulteration of heroin with clenbuterol is frequently reported [112 ]. In 13 confirmed cases of exposure to clenbuterol in this way, clenbuterol was identified in the blood and or urine of 12 [113 ]. Symptoms included nausea, chest pain, palpitation, dyspnea, and tremor. The physical findings included significant tachycardia and hypotension, and there was laboratory evidence of hyperglycemia, hypokalemia, and increased lactate concentrations six patients had biochemical evidence of myocardial injury. Ten were given beta-adrenoceptor antagonists without adverse effects. 

---