I don't have chlamydia. so would flagyl and injection of cefriaxone be enough to treat pid?

Coverage: The point is that all the bacteria that potentially could cause vaginitis or pelvic inflammatory disease are covered by the chosen antibiotics. Flagyl covers trichomonas and gardnerella (bacterial vaginosis), ceftrioxone covers gonorrhea.

PID: Pelvic inflammatory disease occurs when the upper genital tract of a woman is infected. The cause is normally polymycrobial and broad spectrum antibiotics are commonly used. Ceftriaxone and Flagyl should adequately treat the infection, however some patients will require extra antibiotics.