From the Research
When converting from oral Coreg (carvedilol) to intravenous (IV) form, the recommended approach is to use IV metoprolol as there is no IV formulation of carvedilol available in most countries. For patients on oral carvedilol, switch to IV metoprolol at a ratio of approximately 1:2 - meaning 25 mg of oral carvedilol would convert to about 50 mg of IV metoprolol per day, divided into doses of 5-15 mg every 6-8 hours. This conversion is not exact due to differences in pharmacology between the two medications, as carvedilol is a non-selective beta-blocker with alpha-blocking properties, while metoprolol is a selective beta-1 blocker 1. When the patient can resume oral medications, they can be transitioned back to their original carvedilol regimen. Monitor blood pressure and heart rate closely during this conversion as individual responses may vary. The goal is to maintain similar hemodynamic effects while using the available IV beta-blocker. Once the patient can take oral medications again, they should be switched back to their original carvedilol dosing regimen. It's worth noting that carvedilol has been shown to have a more favorable effect on mortality compared to metoprolol in patients with chronic heart failure, as demonstrated in the Carvedilol Or Metoprolol European Trial (COMET) 2. However, in the context of converting from oral to IV, the primary concern is maintaining adequate beta-blockade and hemodynamic stability, rather than the specific mortality benefits associated with each medication. Therefore, the use of IV metoprolol as a substitute for oral carvedilol is a practical and effective approach in clinical practice.