Antibiotic Guide

ARMC Antibiogram

Updated 7/30/20; DGI added 2/23/21

Verify all patients with penicillin allergies. 10% of patients report penicillin allergies, but 90% of them can actually tolerate it. The true risk of anaphylaxis with penicillin is 0.01%. Ask the patient what reaction they have, when they last received a penicillin or cephalosporin, and review prior visits to see if they ever received penicillins or cephalosporins successfully. It is generally OK to g IVe cephalosporins for penicillin allergies unless there is a history of anaphylaxis to penicillins. Additionally, IgE sensitivity to penicillins tends to go away after 10 years.

Abdominal Infection

Community acquired

Outpatient:

ciprofloxacin 500 mg PO BID + metronidazole 500 mg PO TID x7d
amoxicillin/clavulanate 875/125 PO BID x7d

Inpatient

ceftriaxone 2 g IV q24h + metronidazole 500 mg IV q8h

If Pseudomonas suspected or severe (abscess, gangrenous, perforated):

cefepime 2 g IV q12h + metronidazole 500 mg IV q8h

Hospital acquired:

vancomycin 15-20 mg/kg IV q12h + piperacillin/tazobactam 4.5g IV q8h

Severe PCN allergy:

levofloxacin 750 mg IV q24h (OR ciprofloxacin) + metronidazole 500 mg IV q8h

Abscess

Mild

I&D only
no abx indicated unless extensive surrounding cellulitis

TMP/SMX DS 2 tab PO BID x7d
clindamycin 450 mg PO TID x7d
doxycycline 100 mg PO BID x7d

If extensive surrounding cellulitis, add:

cephalexin 500 mg PO qID x7d
dicloxacillin 500 mg PO QID x7d

Moderate:

cefazolin 2g IV q8h
nafcillin 2g IV q4h
clindamycin 600 mg IV q8h

Diabetic foot ulcer:

non- septic: hold antibiotics until culture obtained
septic/unstable: refer to severe sepsis order set

If MRSA suspected:

add vancomycin 15-20 mg/kg IV q12h

Blood Cx

Severe:

refer to sepsis order set

Abscess, Lung

ampicillin/sulbactam 3g IV q6h
ceftriaxone 2g IV q24h + metronidazole 500 mg IV q12h
piperacillin/tazobactam 4.5g IV q8h

Severe PCN allergy:

metronidazole 500 mg IV q12h + levofloxaxin 750 mg IV q24h

Abscess, Peritonsillar

Augmentin 875/125 mg PO BID x7-10d
clindamycin 450mg PO Q8H x7-10d
consider Decadron 10mg x1

Abscess, Retropharyngeal

Unasyn 3g IV
ceftriaxone 2g IV + Flagyl 500mg IV
clindamycin 600-900mg IV

Blood Cx

Abscess, Tubo-Ovarian

cefotetan/cefoxitin 2g IV + doxycycline 100mg IV
clindamycin 900mg IV Q8H + gentamicin 3-5 mg/kg IV DAILY

Appendicitis

ceftriaxone 2 g IV q24h + metronidazole 500 mg IV q8h

Severe (abscess, gangrenous, perforated):

cefepime 2g IV q12h + metronidazole 500 mg IV q8h

Severe PCN allergy:

levofloxacin 750 mg IV q24h (OR ciprofloxacin) + metronidazole 500 mg IV q8h

Blood Cx

Arthritis, Septic

vancomycin 15-20 mg/kg IV q12h + ceftriaxone 2g IV q24h

If Pseudomonas suspected:

vancomycin 15-20 mg/kg IV q12h + ceftazidime 2g IV q8h

If Neisseria gonorrhoeae suspected:

ceftriaxone 1g IV/IM q24h x7d + azithromycin 1 gm PO x1

Severe PCN allergy:

vancomycin 15-20 mg/kg IV q12h + ciprofloxacin 400 mg IV q8h (works for sickle cell)
consider rifampin 600 mg IV for infected hardware

Synovial Fluid Cx

Aspiration Pneumonia

Unasyn 3g IV
ceftriaxone 1g IV + Flagyl 500mg IV
Zosyn 4.5g IV

Blood and Sputum Cx

Severe PCN allergy:

Flagyl 500mg IV + levofloxaxin 750mg IV

Bites

Outpatient

Treat all bites undergoing primary closure, on face / hands / feet, close to bone / joint, deep puncture wounds, crush injury, or immunocompromised

amoxicillin/clavulanate 875/125mg PO BID x7d
doxycycline 100mg PO BID x7d
clindamycin 450mg PO Q8H + TMP/SMX DS 1-2 tab PO BID x7d

Tdap and Rabies prophylaxis depending on history

Inpatient

ampicillin/sulbactam 3g IV q6H

Severe PCN allergy:

clindamycin 900 mg IV q8h + levofloxacin 750 mg PO q24h

Tdap and Rabies prophylaxis depending on history

Botulism

See guide

C. diff

Mild/Moderate:

vancomycin 125 mg PO q6H
fidaxomicin 200 mg PO q12h

Fulminant/Severe:

vancomycin 500 mg PO q6h + metronidazole 500 mg IV q8h

Stool Sample

CAP

Outpatient

azithromycin (Z-pak 500 mg 1st day, then 250 mg DAILY x 4)
doxycycline 100 mg PO BID x5-7d
levofloxacin 750 mg PO DAILY x5d

Outpatient w/significant co-morbidities

amoxicillin/clavulanate 875/125 mg PO BID x5-7d + azithromycin PO (Z-pak)
amoxicillin/clavulanate 875/125 mg PO BID + doxycycline 100 mg PO BID x5-7d

Inpatient

ceftriaxone 2 g IV q24h + azithromycin 500 mg q24h
ceftriaxone 2 g IV q24h + doxycycline 100 mg q12h
levofloxacin 750 mg IV q24h

Blood and Sputum Cx

If concern for MRSA or Pseudomonas:

vancomycin 15-20 mg/kg IV q12h + ceftazidime 2 g IV q8h

If ICU:

add amikacin 10-15 mg/kg IV q24h

Severe PCN allergy:

vancomycin 15-20 mg/kg IV q12h + aztreonam 2 g IV q8h +/- amikacin 10-15 mg/kg IV q24h

Cellulitis

Mild:

non-purulent

cephalexin 500 mg PO qID x7d
dicloxacillin 500 mg PO QID x7d
treat x14d if diabetic foot ulcer

purulent

TMP/SMX DS 2 tab PO BID x7d
clindamycin 450 mg PO TID x7d
doxycycline 100 mg PO BID x7d
if single abscess < 2 cm with no comorbidities and normal vitals: I&D only; no antibiotics

Moderate:

cefazolin 2g IV q8h
nafcillin 2g IV q4h
clindamycin 600 mg IV q8h

Diabetic foot ulcer:

non- septic: hold antibiotics until culture obtained
septic/unstable: refer to severe sepsis order set

If MRSA suspected:

add vancomycin 15-20 mg/kg IV q12h

Blood Cx

Severe:

refer to sepsis order set

Cellulitis, Orbital

vancomycin 15-20mg IV + Unasyn 3g IV
vancomycin 15-20mg IV + ceftriaxone 2g IV +/- Flagyl 500mg IV

Severe PCN allergy:

vancomycin 15-20mg IV + levofloxacin 750mg IV +/- Flagyl 500mg IV

Blood Cx

Cellulitis, Pre-septal

Augmentin 875/125mg PO BID x10d
clindamycin 450mg PO Q8H x10d
Keflex 500mg PO Q6H + Bactrim DS 1-2 tab BID x10d

Cervicitis

ceftriaxone 500 mg IM x1 + azithromycin 1g PO x1

If enteric pathogen strongly suspected:

consider levofloxacin 500 mg PO DAILY x7-10d

If azithromycin allergy:

ceftriaxone 500 mg IM x1 + doxycycline 100 mg PO BID x7d

If severe PCN allergy:

gentamicin 240 mg IM x1 + azithromycin 2g PO x1

Cholangitis

ceftriaxone 2 g IV q24h + metronidazole 500 mg IV q8h

Pseudomonas suspected or severe (abscess, gangrenous, perforated):

cefepime 2g IV q12h + metronidazole 500 mg IV q8h

Severe PCN allergy:

levofloxacin 750 mg IV q24h (OR ciprofloxacin) + metronidazole 500 mg IV q8h

Blood Cx

Cholecystitis

ceftriaxone 2 g IV q24h + metronidazole 500 mg IV q8h

Pseudomonas suspected or severe (abscess, gangrenous, perforated):

cefepime 2g IV q12h + metronidazole 500 mg IV q8h

Severe PCN allergy:

levofloxacin 750 mg IV q24h (OR ciprofloxacin) + metronidazole 500 mg IV q8h

Cystitis

cephalexin 500mg PO BID x5d (ok during pregnancy too)
nitrofurantoin ER (Macrobid) 100mg PO BID x5d
ciprofloxacin 250 mg PO BID x 3d
TMP/SMX DS 1 tab PO BID x5d
fosfomycin 3g PO x1

Complicated: see pyelo inpatient (obstruction, catheters, reflux, nosocomial, pregnancy, immunocompromised)

Diabetic Foot Ulcer

non- septic: hold antibiotics until culture obtained
septic/unstable: refer to severe sepsis order set

refer to SSTI order set

Diverticulitis

Outpatient:

ciprofloxacin 500 mg PO BID + metronidazole 500 mg PO TID x7d
amoxicillin/clavulanate 875/125 PO BID x7d

Inpatient mild:

ceftriaxone 2 g IV q24h + metronidazole 500 mg IV q8h

Inpatient severe:

cefepime 2 g IV q12h + metronidazole 500 mg IV q8h

Severe PCN allergy:

levofloxacin 750 mg IV q24h (OR ciprofloxacin) + metronidazole 500 mg IV q8h

Blood Cx

Encephalitis

acyclovir 10mg/kg IV

CSF and Blood Cx

Epididymitis

ceftriaxone 500 mg IM x1 + doxycycline 100 mg PO BID x7d

If enteric pathogen strongly suspected:

consider levofloxacin 500 mg PO DAILY x7-10d

If compliance is an issue:

ceftriaxone 500 mg IM x1 + azithromycin 1g PO x1

If severe PCN allergy:

gentamicin 240 mg IM x1 + azithromycin 2g PO x1

Urine Cx

Gonorrhea and Chlamydia PCR

Epiglottitis

ceftriaxone 1g IV
Unasyn 3g IV

If severe infection or immunocompromised:

vancomycin 15-20mg/kg IV + cefepime 2g IV

Severe PCN allergy:

levofloxacin 750mg IV

Blood Cx

Fracture, Open

Clean, linear laceration without extensive soft tissue injury, flaps, or avulsion:

cefazolin 2g IV q8h monotherapy

If fracture > 1cm with extensive soft tissue damage or heavily contaminated:

add gentamicin 5mg/kg IV q24h

If soil contamination:

consider adding penicillin VK 2M units IV q4h

Severe PCN allergy:

vancomycin 15-20 mg/kg IV q12h +/- gentamicin 5 mg/kg IV q24h

HAP

Risk factors: hospitalized 2+ days in last 90 days, IV antibiotics / chemotherapy in last 30 days, nursing home, dialysis, immunosuppressed

vancomycin 15-20 mg/kg IV q12h + ceftazidime 2 g IV q8h

If ICU:

add amikacin 10-15 mg/kg IV q24h

Severe PCN allergy:

vancomycin 15-20 mg/kg IV q12h + aztreonam 2 g IV q8h +/- amikacin 10-15 mg/kg IV q24h

Blood and Sputum Cx

Ludwig’s Angina

Unasyn 3g IV
ceftriaxone 2g IV + Flagyl 500mg IV
clindamycin 600mg IV

If immunocompromised: consider MRSA + Pseudomonas coverage

Blood Cx

Lung Abscess

ampicillin/sulbactam 3g IV q6h
ceftriaxone 2g IV q24h + metronidazole 500 mg IV q12h
piperacillin/tazobactam 4.5g IV q8h

Severe PCN allergy:

metronidazole 500 mg IV q12h + levofloxaxin 750 mg IV q24h

Mastoiditis

Unasyn 3g IV

If concerned for MRSA:

add vancomycin 15-20 mg/kg IV

Severe PCN allergy:

aztreonam 2g IV (preferred) OR clindamycin 600mg IV

Blood Cx

Meningitis

vancomycin 15-20 mg/kg IV q12h + ceftriaxone 2g IV q12h
add dexamethasone 10 mg IV (with 1st antibiotic)

If age > 50 or immunocompromised:

add ampicillin 2g IV q6h for Listeria

If concern for HSV/encephalitis:

add acyclovir 10 mg/kg IV q8h

If hospital-acquired:

vancomycin 15-20 mg/kg IV q12h + ceftazidime 2g IV q8h

If Neisseria gonorrhoeae suspected:

ceftriaxone 1-2g IV/IM q12-24h x 10-14d + azithromycin 1 gm PO x1

Necrotizing Fasciitis

clindamycin 900 mg IV FIRST for anti- toxin effects
then vancomycin 15-20 mg/kg IV q12h + piperacillin/tazobactam 4.5g IV q8h

Severe PCN allergy:

clindamycin 900 mg IV + vancomycin 15-20 mg/kg IV q12h + meropenem 2g IV q8h

Wound + Blood Cx

Open Fracture

Clean, linear laceration without extensive soft tissue injury, flaps, or avulsion:

cefazolin 2g IV q8h monotherapy

If fracture > 1cm with extensive soft tissue damage or heavily contaminated:

add gentamicin 5mg/kg IV q24h

If soil contamination:

consider adding penicillin VK 2M units IV q4h

Severe PCN allergy:

vancomycin 15-20 mg/kg IV q12h +/- gentamicin 5 mg/kg IV q24h

Orbital Cellulitis

vancomycin 15-20mg IV + Unasyn 3g IV
vancomycin 15-20mg IV + ceftriaxone 2g IV +/- Flagyl 500mg IV

Severe PCN allergy:

vancomycin 15-20mg IV + levofloxacin 750mg IV +/- Flagyl 500mg IV

Blood Cx

Osteomyelitis

hold antibiotics until culture obtained if non-septic/stable

vancomycin 15-20 mg/kg IV q12h + ceftriaxone 2g IV q24h

If Pseudomonas suspected:

vancomycin 15-20 mg/kg IV q12h + ceftazidime 2g IV q8h

Severe PCN allergy:

vancomycin 15-20 mg/kg IV q12h + ciprofloxacin 400 mg IV q8h (works for sickle cell)
consider Rifampin 600 mg IV for infected hardware

Otitis Media

amoxicillin 45 mg/kg PO BID x7-10d

Severe PCN allergy:

azithromycin PO (Z-pak)

If antibiotics in last month or treatment failure:

Augmentin 875/125mg PO BID x7-10d

Peritonitis, Spontaneous Bacterial

ceftriaxone 1g IV

Severe PCN allergy:

ciprofloxacin 400mg IV

Peritonsillar Abscess

Augmentin 875/125 mg PO BID x7-10d
clindamycin 450mg PO Q8H x7-10d
consider Decadron 10mg x1

Pharyngitis

Antibiotics only if concerned for Strep

penicillin VK 500mg PO BID x10d
benzathine penicillin G 1.2 M units x 1
consider Decadron 10mg x1

Severe PCN allergy:

azithromycin 500 mg PO DAILY x5d
clindamycin 300mg PO TID x10d

PID

Outpatient:

ceftriaxone 500 mg IM x1 + doxycycline 100 mg PO BID x 14d

If recent instrumentation or concern for BV/trichomonas:

add metronidazole 500 mg q12h

Inpatient:

cefoxitin 2 g IV q6H + doxycycline 100 mg IV q12h
clindamycin 900 mg IV q8h + gentamicin 3-5 mg/kg IV q24h

Pneumonia, aspiration

Unasyn 3g IV
ceftriaxone 1g IV + Flagyl 500mg IV
Zosyn 4.5g IV

Blood and Sputum Cx

Severe PCN allergy:

Flagyl 500mg IV + levofloxaxin 750mg IV

Pneumonia (CAP)

Outpatient

azithromycin (Z-pak 500 mg 1st day, then 250 mg DAILY x 4)
doxycycline 100 mg PO BID x5-7d
levofloxacin 750 mg PO DAILY x5d

Outpatient w/significant co-morbidities

amoxicillin/clavulanate 875/125 mg PO BID x5-7d + azithromycin PO (Z-pak)
amoxicillin/clavulanate 875/125 mg PO BID + doxycycline 100 mg PO BID x5-7d

Inpatient

ceftriaxone 2 g IV q24h + azithromycin 500 mg q24h
ceftriaxone 2 g IV q24h + doxycycline 100 mg q12h
levofloxacin 750 mg IV q24h

Blood and Sputum Cx

If concern for MRSA or Pseudomonas:

vancomycin 15-20 mg/kg IV q12h + ceftazidime 2 g IV q8h

If ICU:

add amikacin 10-15 mg/kg IV q24h

Severe PCN allergy:

vancomycin 15-20 mg/kg IV q12h + aztreonam 2 g IV q8h +/- amikacin 10-15 mg/kg IV q24h

Pneumonia (HAP)

Risk factors: hospitalized 2+ days in last 90 days, IV antibiotics / chemotherapy in last 30 days, nursing home, dialysis, immunosuppressed

vancomycin 15-20 mg/kg IV q12h + ceftazidime 2 g IV q8h

If ICU:

add amikacin 10-15 mg/kg IV q24h

Severe PCN allergy:

vancomycin 15-20 mg/kg IV q12h + aztreonam 2 g IV q8h +/- amikacin 10-15 mg/kg IV q24h

Blood and Sputum Cx

Pneumonia (VAP)

vancomycin 15-20mg/kg IV + cefepime 2g IV +/- levofloxacin 750mg IV

Severe PCN allergy:

vancomycin 15-20mg/kg IV + aztreonam 2g IV + levofloxacin 750mg IV

Blood and Sputum Cx

Pre-septal Cellulitis

Augmentin 875/125mg PO BID x10d
clindamycin 450mg PO Q8H x10d
Keflex 500mg PO Q6H + Bactrim DS 1-2 tab BID x10d

Pyelonephritis

Outpatient

cephalexin 500mg PO QID x10d; consider ceftriaxone 1g IM x1 prior to discharge
ciprofloxacin 500 mg PO BID x7d
levofloxacin 750 mg PO DAILY x7d
TMP/SMX DS 1 tab PO BID x14d

Inpatient

refer to prior urine cultures and adjust antibiotic selection accordingly

ceftriaxone 2g IV q24h
ceftazidime 2g IV q8h
ciprofloxacin 400 mg IV q12h
levofloxacin 750 mg IV q24h

If hospital-acquired:

ceftazidime 2g IV q8h

If ICU:

add amikacin 10-15 mg/kg IV q24h

Retropharyngeal Abscess

Unasyn 3g IV
ceftriaxone 2g IV + Flagyl 500mg IV
clindamycin 600-900mg IV

Blood Cx

Sepsis

Tailor to source; refer to sepsis order set

If source completely unknown

vancomycin 15-20 mg/kg IV q12h + cefepime 2g IV q12h
add metronidazole 500 mg IV q8h if concern for anaerobes

Blood Cx

Septic Arthritis

vancomycin 15-20 mg/kg IV q12h + ceftriaxone 2g IV q24h

If Pseudomonas suspected:

vancomycin 15-20 mg/kg IV q12h + ceftazidime 2g IV q8h

Severe PCN allergy:

vancomycin 15-20 mg/kg IV q12h + ciprofloxacin 400 mg IV q8h (works for sickle cell)
consider rifampin 600 mg IV for infected hardware

Synovial Fluid Cx

Sinusitis

Antibiotics only if symptoms > 7-10 days

Augmentin 875/125mg PO BID x7d
doxycycline 100mg PO BID x7d

Spontaneous Bacterial Peritonitis

ceftriaxone 2 g IV q24h

Severe PCN allergy:

ciprofloxacin 400 mg IV q12h

SSTI

Mild:

non-purulent

cephalexin 500 mg PO qID x7d
dicloxacillin 500 mg PO QID x7d
treat x14d if diabetic foot ulcer

purulent

TMP/SMX DS 2 tab PO BID x7d
clindamycin 450 mg PO TID x7d
doxycycline 100 mg PO BID x7d
if single abscess < 2 cm with no comorbidities and normal vitals: I&D only; no antibiotics

Moderate:

cefazolin 2g IV q8h
nafcillin 2g IV q4h
clindamycin 600 mg IV q8h

Diabetic foot ulcer:

non- septic: hold antibiotics until culture obtained
septic/unstable: refer to severe sepsis order set

If MRSA suspected:

add vancomycin 15-20 mg/kg IV q12h

Blood Cx

Severe:

refer to sepsis order set

Syphilis

Early Stage

penicillin G benzathine 2.4 M units IM x1

Late Stage

penicillin G benzathine 2.4 M units IM qweekly x3

Neurosyphilis

penicillin G 3-4 M units IV q4h x10-14d

Severe PCN allergy:

doxycycline 100 mg PO BID x14d (28d for late stage)

PCN desensitization still preferred if possible

Tonsillitis

Antibiotics only if concerned for Strep

penicillin VK 500mg PO BID x10d
benzathine penicillin G 1.2M units x 1
consider Decadron 10mg x1

Severe PCN allergy:

azithromycin 500mg PO DAILY x5d OR clindamycin 300mg PO Q8H x10d

Tubo-Ovarian Abscess

cefotetan/cefoxitin 2g IV + doxycycline 100mg IV
clindamycin 900mg IV Q8H + gentamicin 3-5 mg/kg IV DAILY

Ulcer, Diabetic Foot

Outpatient

Keflex 500mg PO Q6H x14d
clindamycin 450mg PO Q8H
doxycycline 100mg PO BID x14d

If MRSA suspected:

add Bactrim DS 1tab PO BID

Inpatient

ceftriaxone 1g IV
clindamycin 600mg IV + levofloxacin 750mg IV

If MRSA suspected:

add vancomycin 15-20mg/kg IV

If severe:

vancomycin 15-20mg/kg IV + cefepime 2g IV +Flagyl 500mg IV
vancomycin 15-20mg/kg IV + Flagyl 500mg IV + aztreonam 2g IV

Wound Cx

Urethritis

ceftriaxone 500 mg IM x1 + azithromycin 1g PO x1

If enteric pathogen strongly suspected:

consider levofloxacin 500 mg PO DAILY x7-10d

If azithromycin allergy:

ceftriaxone 500 mg IM x1 + doxycycline 100 mg PO BID x7d

If severe PCN allergy:

gentamicin 240 mg IM x1 + azithromycin 2g PO x1

Urine Cx

Gonorrhea and Chlamydia PCR

UTI

cephalexin 500mg PO BID x5d (ok during pregnancy too)
nitrofurantoin ER (Macrobid) 100mg PO BID x5d
ciprofloxacin 250 mg PO BID x 3d
TMP/SMX DS 1 tab PO BID x5d
fosfomycin 3g PO x1

Complicated: see pyelo inpatient (obstruction, catheters, reflux, nosocomial, pregnancy, immunocompromised)

VAP

vancomycin 15-20mg/kg IV + cefepime 2g IV +/- levofloxacin 750mg IV

Severe PCN allergy:

vancomycin 15-20mg/kg IV + aztreonam 2g IV + levofloxacin 750mg IV

Blood and Sputum Cx