If Sinus bradycardia is noted, what is the first drug to administer?

When sinus bradycardia is observed, the initial management often includes administering oxygen, especially if the patient shows signs of inadequate perfusion or oxygenation. Oxygen is crucial as it can help improve the oxygen delivery to tissues, especially in situations where bradycardia might lead to diminished cardiac output or hypoxia.

Monitoring the patient's oxygen saturation and providing supplemental oxygen is a fundamental step before proceeding to other interventions or medications. This initial support helps stabilize the patient and can alleviate respiratory distress.

Other interventions or drugs, such as those that may be listed in the options, might come into play if there are further complications or if specific symptoms arise. However, providing adequate oxygenation is a primary concern and a necessary first step in managing sinus bradycardia, particularly when adverse symptoms are present.