Management of β-blocker and calcium channel blocker poisoning
β-blocker and calcium channel-blockers can cause life-threatening toxicity due to cardiogenic shock. Both β-blockers and calcium channel-blockers are heterogenous groups of drugs and particular drugs, such as propranolol, diltiazem, and verapamil are far more toxic than the others in their class. The most important investigations in β-blocker and calcium channel-blocker overdose are an electrocardiogram, blood glucose measurement, and electrolytes. Like most overdoses, supportive treatment is the most important, with emphasis on the primary pathophysiology. Early decontamination should be considered based on the severity of the poisoning. Treatment of β-blockers and calcium channel-blockers poisoning, using absolute blood pressure as an endpoint can be misleading and measuring cardiac output can be more informative in gauging response to treatment. There are no specific antidotes, although β-agonists may be effective in β-blocker overdose and calcium has been shown to be effective in calcium channel-blocker overdose. The choice of inotropes and/or vasopressors will differ for β-blockers and calcium channel-blockers. These include isoprenaline, high dose insulin euglycaemia, phosphodiesterase inhibitors, and other catecholaminergic inotropes for β-blocker poisoning and adrenaline, high dose insulin euglycaemia and vasopressors for calcium channel-blocker poisoning.