Thanks for writing to us with your health concern.
Doxycycline will not reduce the efficacy of the Implanon.
Only certain antibiotics that induce enzymes which will in turn, hasten metabolism of the hormones, can reduce the efficacy of Implanon / birth control pills.
Doxycycline does not belong to that class.
Do not worry on that score.
Patient replied :
Thank You Very much! I'm glad I got that all cleared up! Thanks again