I was able to get away with drinking the same day as donating blood in my younger days. I would just drink half of what I’d normally drink to compensate for decreased tolerance.

I gave blood recently (now in my 50s). I had one drink with an appetizer and dinner after having lunch and drinking a lot of water post blood donation. I was able to get home ok and bought an electrolyte drink on the way home. If I had a second alcoholic drink, I’m not sure I’d be able to get home ok. Going to have to plan dinners with friends on non blood donor days or get a mocktail instead. Place I went to had lavender lemonade. Will go for that next time.