I'm on the Nexplanon implant and have been for 8 months. Okay this is going to sound like a strange question but will my boyfriends medication effect the effectiveness of MY birth control if he comes inside me? He is on two antibiotics: Smz-Tmp and Cephalexin. Also it's my understanding that antibiotics won't even effect the Nexplanon even if I was taking them. I just want to double check. Thank you.