Shorter is better

AMMI

Infection	Duration	Comments
Urinary Tract Infections
Women or adolescents with uncomplicated cystitis	Nitrofurantoin for 5 days, TMP-SMX for 3 days, fosfomycin for 1 day	young non-pregnant female adolescents or adults with normal urinary tracts and normal renal function
Children with febrile urinary tract infection	7 to 14 days	assumes upper tract involvement if febrile
Adults with pyelonephritis and urosepsis	consider initial dose of IV; quinolones or beta-lactams for 7 days	excludes patients with urogenital abnormalities, stents, or drains; duration depends on clinical response
Respiratory Tract Infections
Streptococcal pharyngitis	10 days (penicillin V or amoxicillin)	studies limited to pediatrics
Acute otitis media	10 days (6 months to 2 years) or 5 days (over 2 years)	if moderately to severely ill with bulging tympanic membrane
Acute uncomplicated sinusitis	5 to 7 days	reassess at 7 days
Community-acquired pneumonia	5 to 7 days	excludes patients with underlying lung disease, immunosuppression, and empyema; depends on clinical response
Hospital-acquired pneumonia	≤7 days	excludes severely immunosuppressed patient or those with collections/abscesses
Acute exacerbation of COPD	5 to 7 days	only if antibiotics are indicated
Intra-abdominal Infections
Uncomplicated appendicitis	pre-operative antibiotics only	if gangrenous or perforated, continue for additional 24 to 48 hours after source control
Traumatic bowel perforation	up to 24 hours post-operatively	if operated on within 12 hours of trauma
Gastroduodenal perforation	up to 24 hours post-operatively	if operated on within 24 hours
Intra-abdominal abscess	<7 days	if source control is adequate, regardless of whether drainage is still in place
Skin Infections
Uncomplicated cellulitis	5 to 7 days
Bone and Joint Infections
Children with acute osteomyelitis	3 to 4 weeks	transition to oral therapy once clinically improving and CRP decreasing
Adults with acute vertebral osteomyelitis	6 weeks	excludes those with implantable devices; may be longer for Salmonella or Brucella
Adults with acute septic arthritis	2 weeks (small joints) or 4 weeks (large joints)	duration after surgical drainage
Bacteremia
Enterobacterales	7 days	if source control and not associated with syndrome requiring longer therapy
Staphylococcus aureus (uncomplicated)	14 days (IV)	if other focusses are excluded
Staphylococcus aureus (complicated)	4 to 6 weeks (IV)
Streptococcus pneumoniae, with pneumonia	5 to 7 days	if clinically improving

Brad Spellberg

Diagnosis	Short (d)	Long (d)	Result	# RCTs
Community-acquired pneumonia	3-5	5-14	=	10
Ventilator-associated pneumonia	8	15	=	2
Pyelonephritis	5-7	10-14	=	7
Intra-abdominal infections	4	10	=	2
Gram-negative bacteremia	7	14	=	2
Cellulitis	5-6	10	=	4
Chronic osteomyelitis	42	84	=	2
Diabetic foot osteomyelitis, after debridement	21	42	=	1
Septic arthritis	14	28	=	1
Removed orthopedic implant	28	42	=	1
Acute exacerbation of COPD or sinusitis	≤5	≥7	=	>25
Febrile neutropenia	Afebrile x72 h	+ ANC >500	=	1
Latent tuberculosis infection	1-4 mo	6-12 mo	=	8
Plasmodium vivax malaria	7	14	=	1

Further Reading

• Brad Spellber's Shorter is Better website
• AMMI Practice Point: Duration of Antibiotic Therapy for Common Infections