2290 The virtue of temperance disposes us to avoid every kind of excess: the abuse of food, alcohol, tobacco, or medicine. Those incur grave guilt who, by drunkenness or a love of speed, endanger their own and others’ safety on the road, at sea, or in the air. 2291 The use of drugs [alchohol is a “drug”] inflicts very grave damage on human health and life. Their use, except on strictly therapeutic grounds, is a grave offense. Clandestine production of and trafficking in drugs are scandalous practices. They constitute direct co-operation in evil, since they encourage people to practices gravely contrary to the moral law.
Accordingly, the catechism only condemns the “abuse” of alcohol and specifically permits it for “therapeutic” reasons. Use of alcohol as a painkiller in the absence of other reasonable alternatives is permitted, and NOT A SIN.