Been on nexplanon over 1 year, taking cefalexin for paronychia.no condoms w husband been having sex should i worry antibiotic makes it less effective?

Drug interaction: No, you should not worry. Some antibiotics can decrease the efficacy of oral birth control pills. This happens due to interaction of the antibiotic with the liver enzymes, which are also used to metabolize ORAL birth control pills. Since your Nexplanon is not an oral medication, its efficacy should not be affected by your antibiotic.