Which medication can be used for acute rate control in a patient with atrial fibrillation?

Metoprolol is a beta-blocker that is commonly used for acute rate control in patients with atrial fibrillation. In this context, it works by slowing down the heart rate, which is particularly important when dealing with the rapid ventricular response that can occur in atrial fibrillation. The mechanism involves blocking beta-adrenergic receptors, which reduces the heart's excitability and lowers its rate of contraction. This therapeutic effect helps in stabilizing the patient and preventing complications such as heart failure or excessive myocardial oxygen demand.

While other medications mentioned may have roles in managing atrial fibrillation, their primary indications differ from acute rate control. For example, amiodarone is an antiarrhythmic that can be used to control rhythm or rate but is not typically the first-line choice for immediate rate control. Dronedarone and flecainide are also antiarrhythmics that may be prescribed for chronic management or rhythm control rather than for acute rate control in the context of urgent care situations. Thus, metoprolol emerges as the preferred agent in this scenario due to its rapid action and effectiveness in achieving controlled heart rates during episodes of atrial fibrillation.