By which route is propranolol primarily administered for the treatment of angina?

Propranolol is primarily administered orally for the treatment of angina. This administration route allows for effective absorption and provides sustained plasma concentration over time, which is essential for managing chronic conditions like angina. Oral administration typically leads to a convenient dosing schedule and improved patient adherence compared to other routes.

While propranolol can be given by intravenous or intramuscular routes in certain clinical settings, these methods are not the standard for ongoing management of angina. The oral route is thus preferred, being practical for both acute and chronic therapy, as it effectively controls symptoms and helps prevent anginal attacks through its action as a beta-adrenergic antagonist. Sublingual administration is primarily associated with rapid relief of acute episodes, but is not used for chronic management in the same way as the oral route.