University of Pennsylvania Medical Center Guidelines for Antibiotic Use



Clinical Setting Empiric Treatment Likely Pathogens Definitive Treatment Dosage Regimen Duration
Malignant Otitis Externa1
Mild/moderate levofloxacin P. aeruginosa same as empiric 500mg PO q 24 hour 2-6 weeks
Severe piperacillin + gentamicin P. aeruginosa

same as empiric

(switch to levofloxacin when clinically indicated)

piperacillin 4 gm q 6 hour

gentamicin - see this link

Acute Sinusitis


Mod/severe (temp., facial pain,TMP/SMX failure)


amoxicillin/ clavulanic acid2

S. pneumoniae amoxicillin3 875 mg PO bid 10 days
H. influenzae TMP/SMX 160/800mg (1 double strength tablet) PO BID
M. catarrhalis
oral anaerobes
Tonsillitis/ Pharyngitis
Mild penicillin V4 group A streptococcus penicillin V 250mg PO q 6 hour -10 days





Moderate5 benzathine penicillin G4 IM x 1 or penicillin V same as above

benzathine penicillin G


penicillin V

1.2mu IM x 1 dose once


250mg PO q 6 hour -10 days

Severe (abscess6 or treatment failure) ampicillin/sulbactam

group A streptococcus

H. influenzae

S. aureus

oral anaerobes

ampicillin/sulbactam 1.5gm IV q 6 hour
10-14 days6

1Surgical debridement may be indicated

2Amoxicillin/clavulanic acid dose: 875 mg PO BID x 10 days

3Review susceptibilities-S. pneumoniae resistance is about 15 to 25 %

4If penicillin allergy is rash then cephalexin 250 mg po qid; if allergy severe (urticaria, angioedema, or anaphylaxis) then eyrthromycin 250 mg po qid (check susceptibility - resistance rate 5-10%)

5 If multiple or recurrent episodes, consider clindamycin 150 mg po qid (check suscept - 5-10% resistance), amoxicillin/clavulanic acid 500 mg po bid or benzathine penicillin 1.2 mu IM once. Rifampin can be added to eradicate streptococci from the pharynx (600 mg po qd x 4 d)

6Abscess should be drained

updated 4/1/2003 by Lori LaRosa

Back to Table of Contents