Symptoms: Overdose may cause pronounced hypotension possibly leading to collapse, sinus bradycardia with or without isorhythmic dissociation, and atrioventricular conduction disturbances. Other symptoms eg, tiredness, irritability, somnolence, hypothermia, hyperglycaemia, and nausea may occur.
Treatment: There is no specific antidote for diltiazem. Absorption should be prevented by eg, with gastric lavage, osmotic diuresis and/or administration of activated charcoal. Respiration, hemodynamics and fluid and electrolyte balance should be monitored. Hypotension can be treated with IV dopamine or calcium chloride. Bradycardia and severe atrioventricular block have been treated with atropine or cardiac pacing. Vasopressors, inotropic agents and glucagon may also be used. Otherwise the treatment is symptomatic.