From the Guidelines
Beta blockers are contraindicated in cocaine overdose because they can worsen coronary spasm by causing unopposed alpha-adrenergic receptor stimulation.
Rationale
- Cocaine stimulates both alpha- and beta-adrenergic receptors, leading to increased blood pressure, heart rate, and coronary vasoconstriction 1.
- Beta blockers, which block beta-adrenergic receptors, can lead to unopposed alpha-adrenergic receptor stimulation, resulting in increased coronary vasoconstriction and potentially worsening coronary spasm 1.
- This is supported by evidence from a single double-blind, randomized, placebo-controlled trial that showed beta-adrenergic blockade augmented cocaine-induced coronary artery vasoconstriction 1.
Treatment Approach
- In patients with cocaine-induced coronary spasm, benzodiazepines and nitroglycerin are preferred for management of hypertension and tachycardia 1.
- Calcium channel blockers, such as diltiazem and verapamil, can also be used to treat patients with tachyarrhythmias under close ECG monitoring 1.
- Labetalol, an alpha and beta blocker, is not recommended due to its potential to induce coronary artery vasoconstriction 1.
Clinical Considerations
- Patients with cocaine overdose should be treated with caution, and beta blockers should be avoided in patients with signs of acute intoxication, such as euphoria, tachycardia, and/or hypertension 1.
- In patients with coronary ischemia, treatment with nitroglycerine and aspirin is recommended, in addition to benzodiazepines 1.
From the Research
Beta Blockers in Cocaine Overdose
- Beta blockers are generally contraindicated in patients presenting with acute cocaine intoxication due to concern for unopposed α-receptor stimulation 2, 3, 4, 5.
- The concern is that beta blockers may worsen cocaine-induced coronary vasoconstriction by allowing unopposed alpha-adrenergic receptor stimulation, potentially leading to increased cardiovascular complications 3, 4, 5.
- However, some studies have reported that beta-blocker treatment did not increase adverse events in patients with cocaine-associated chest pain or recent cocaine use 2, 6.
- The use of mixed β-/α-blockers, such as labetalol and carvedilol, may be safer in patients with cocaine-induced cardiovascular toxicity, as they can counteract both beta and alpha-adrenergic effects 4, 5.
Clinical Evidence
- A systematic review and meta-analysis of observational studies found no significant difference in in-hospital all-cause mortality and myocardial infarction between patients who did and did not receive beta-blocker treatment during their hospital stay for cocaine-associated chest pain or recent cocaine use 2.
- A retrospective review of patients admitted with cocaine-induced chest pain found no statistically significant differences in blood pressure, heart rate, and in-hospital cardiovascular complications between patients who received beta blockers and those who did not 6.
- Other studies have suggested that beta blockers may not be as harmful as originally believed in patients with cocaine intoxication, and that further clinical studies are needed to investigate this topic 2, 3, 5.