We’re on hold for a bit 😩 please read!!

To start off my husband is 26 and I’m 25

My husband had a food allergy and was prescribed meds and was given an injection. We tried having sex last night and his penis went down after being hard And we tried giving it another try but it just wouldn’t go up. It’s first time it’s ever happens to us he only took one doze of the meds yesterday morning at 10:40 and he is supposed to take 2-3 times a day but he didn’t after feeling the side affect and he starts a new job tomorrow so he can’t be like that side effects were: made him drowsy,moody, and had hot flashes through out the day yesterday. Today he tells me he just wants to feel a bit better until we try for baby #2 and I respect that I understand. I just wonder if we should have like protected sex so he cums. I want him to flush his system out if you understand what I mean. So my question is around how long will it take for the injection to flush out his system??