Does Taking Antibiotics Reduce The Effectiveness Of Birth Control Pills?

I am wondering about the effects of Bactrim DS Oral on the Tri-Sprintec birth control pill. I have been taking the birth control for 5 weeks now. I finished the Bactrim DS Oral two weeks earlier? Is it safe for me to have unprotected sex at this time? Will the antibiotic still affect my birth controls accuaracy?