Q: What is the 'rule of thumb' equivalent conversion between Metoprolol and carvedilol ?

Answer:  metoprolol 50mg  = carvedilol 12.5mg

While making change to carvedilol, concern should be considered  about the possibility of symptoms related mainly to α blockade mediated vasodilation. Ideally, slowing the rate of titration or reducing the dose is preffered. It would be prudent not to add other vasodilators such as calcium antagonists, nitrates, or other antihypertensives or diuretics during the switch.