What medication should be used for bradycardia due to beta-blocker or calcium channel blocker overdose if atropine fails?

In cases of bradycardia resulting from an overdose of beta-blockers or calcium channel blockers, the first-line treatment typically involves the use of atropine. However, should atropine prove ineffective, IV glucagon is the preferred next step.

Glucagon works by increasing cyclic adenosine monophosphate (cAMP) levels, which counteracts the negative effects of beta-blockade. It promotes heart rate increase and can improve cardiac contractility, thereby effectively addressing the bradycardia. This is particularly useful in scenarios where standard therapies do not yield the desired results.

While other medications such as IV dopamine, aminophylline, and isoprenaline may have roles in managing bradycardia or supporting cardiac function, glucagon stands out in this specific case of overdose due to the direct effects it has on reversing the incidents caused by beta-blockers and calcium channel blockers. Thus, glucagon not only acts on the symptoms but addresses the underlying pharmacological interactions that are causing the bradycardia.