Can alka-seltzer interfere with nexplanon birth control implant?

No: Alka-seltzer is not known to interfere with Nexplanon. Best wishes!

No effect: The birth control implant (Implanon/Nexplanon) is extremely safe b/c it only releases the progestin, Etonogestrel. There is no estrogen, so the risk of clots is MUCH lower than any combined method. Failure rate is 0.05% in a year, which is almost better than getting your tubes tied. It is effective w/in a week of insertion and won't be affected by ANY antibiotics (except rifampin) or alka-seltzer.