Regimens		Antimicrobial
Recommended		Penicillin G—initial dose: 5 million units IV
		Subsequent dosing: 2.5 million units IV every four hours until delivery
Alternative (if penicillin G not available)		Ampicillin—initial dose: 2 g IV
		Subsequent dosing: 1 g IV every four hours until delivery
Penicillin allergy		Clindamycin (Cleocin)—900 mg IV every eight hours until delivery
	and	or
High risk* for anaphylaxis		Erythromycin—500 mg IV every six hours until delivery
	and
GBS susceptible to clindamycin and erythromycin
Penicillin allergy		Vancomycin (Vancocin)—1 g IV every 12 hours until delivery
	and
High risk* for anaphylaxis
	and
GBS resistance to clindamycin or susceptibility unknown
Penicillin allergy		Cefazolin (Ancef)—initial dose: 2 g IV
	and	Subsequent dosing: 1 g IV every eight hours until delivery
Not at high risk* for anaphylaxis†