3.3 Cardiovascular adverse effects
Cardiovascular adverse effects associated with usual therapeutic doses of benzodiazepines are rare and generally minor (see under Overdose for other rare features). The most frequent adverse effect is hypotension and associated increase in heart rate.
Factors which increase risk
A benzodiazepine may increase the risk of symptomatic hypotension in individuals whose blood pressure is low (eg those who are in shock) or are prone to postural hypotension.
Hepatic and renal impairment can reduce clearance of benzodiazepines and increase the risk of hypotension. The elderly or debilitated are at higher risk of cardiovascular adverse effects of benzodiazepines.
Impaired cardiac function may increase the risk of cardiovascular effects of benzodiazepines, especially if an injectable benzodiazepine is given too quickly or if a high dose is given.
A benzodiazepine should be given at a low dose to elderly or debilitated individuals who are more prone to adverse effects. The dose should be reduced in hepatic or renal impairment.
Facilities for resuscitation must be at hand when a benzodiazepine is given intravenously.
Cardiovascular side effects are rare. Symptomatic hypotension will require supportive care and discontinuation of the benzodiazepine or the dose may need to be reduced. In rare severe reactions, specialist advice should be sought on the use of a benzodiazepine antagonist.
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