TOC  |  Infectious Diseases

Empirical Antibiotic Therapy  

See also Antibiotics meds  

antibiotic-empiric-2008.htm

Condition – see commentaries below

 

Suggested Initial Empirical Regimen

Alternative for Allergies, Intolerance

Pneumonia - Outpatient CAP

(1)

 

Cefpodoxime 200mg po BID plus Doxycycline 100mg po BID x10days

                              OR

Azithromycin 500mg po qd x 5-7days

PCN R – Moxifloxacin 400mg po daily

 

  

Pneumonia - Inpatient CAP

 

 

IV Cefotaxime 1gm q8h + IV or po Azithromycin or IV/po Doxycycline 100mg q12h

IV Moxifloxacin 400mg daily

Cellulitis -  Uncomplicated or Diabetic

(2)

 

Clindamycin 900mg IV q8h +/- Cefazolin 1 gram IV q8h. If diabetic, use vanco alone.

If allergic to Clinda, use Vancomycin per pharmacy.  If allergic to Cefazolin, just use Clinda alone.

Diabetic/Ischemic foot infections with

Amputation risk

(3)

Ceftazidime 1gm q8h + Vanco per pharmacy + Flagyl 500mg q8h

Cipro 500 or 750mg po q 12h or 400mg IV q 12h if can’t take po + Vanco per pharmacy + Flagyl 500mg q8h

Pyelonephritis

(4)

 

 

Gentamicin SDDA or Ceftazidime + Ampicillin 1-2gms q6h Can switch to po TMS (or Cipro if resistant; can also use Keflex) as soon as medically improved and can tolerate po

Cipro 400mg IV q12h - discharge on TMS if sensitive or Cipro if R to TMS; can also use Keflex 500mg QID

Intra abdominal infection including appendicitis, cholecystitis, peritonitis

(5)

Amp 2gms q6h, Flagyl 500mg q8h, Gent SDDA or Zosyn 3gm/0.375gm q6h + Gent

Clinda + Gentamicin SDDA

Clinda + Ceftazidime 1gm q8h

Clinda + Cipro 400mg IV q12h

Meningitis age 18-50         (6)

Age >50 or impaired cellular immunity (add Listeria and GNR)

Head trauma, neurosurg, CNS shunt

If see GPC on gram stain of CSF

Cefotaxime 2gms q4h

Amp 3gms q4-6h + Cefotaxime 2gms q4h + Vanco per pharmacy

Vanco per pharmacy + Ceftazidime 2gms q8h

Vanco + Cefotaxime 2gms q4h

Call ID

Dexamethasone 0.15mg/kg IV (typically 10mg) q6h x2-4days recommended for category Age >50 or GPC on gram stain. Timing is important. See commentary (6)

Neutropenic Fever

 

Ceftazidime alone 1gm q8h; add vanco if clinically septic

Ceftazidime ± Gentamicin

Meropenem 1gm q8h

Sepsis of Unknown Source (7)

Vanco 1 gm q8h + Clinda 900mg q8h + Gent SDDA (or Ceftazidime 1 gm q8h if Cr>2.0)

Vanco alone 1gm q12h if allergic to Clinda

Cipro 400mg IV q12h if allergic to Ceftazidime

 

January 1999, revised July 2000, October 2002, January 2004, March 2004, September 2004, September 2006, Jan 2008

 

 

Notes and Commentaries:

 

(1)   Note that Azithromycin alone is sufficient as an alternative to the combination of Cefpodoxime/Doxy). Pneumonia in nonambulatory residents of long term care facilities may need to be treated as health care associated PNA (HCAP) but this does not necessarily mean they all need vanco and zosyn. Call ID for recommendations.

 

(2)   The mere fact that a patient is diabetic does not indicate a need for anaerobic coverage. This is reserved for more complex ischemic foot infections with amputation risk. However, Clinda has become the drug of first choice b/o the rising incidence of community associated MRSA (CAMRSA) which is often sensitive to Clindamycin. The higher risk of MRSA in DM calls for empiric vanco.

 

(3)   Gentamicin can be used in single daily dosing regimens except when it is used for synergy. This is why you see the note to not use SDDA. Also, consistent with our desires to limit Cipro use, Cipro should definitely be the third option for this condition and additionally can be considered for po use since blood levels are almost the same po and iv.

 

(4)   Again, consistent with our desires to limit Cipro (and by extension, quinolone) use, TMS is always preferred if the organism is sensitive and the patient is not allergic. Can also consider using Keflex although it does not have the advantage of eliminating periurethral colonization like TMS and Cipro do. In addition, the patient can generally be switched to po therapy once they are able to tolerate po drugs and they are hemodynamically stable, even if they were bacteremic. Lastly, also note that there is no indication for the combination of Cipro/Ceftazidime. Use either one or the other but not both.

 

(5)   Note that Clinda is preferred as the anaerobic agent in regimens where there will be poor gram positive coverage such as with Gent or Cipro

 

(6)   The initial approach to meningitis first of all assumes that the presentation is consistent with a bacterial infection since most cases of meningitis are aseptic. Secondly, antibiotic coverage varies depending on various factors as listed. A gram stain of CSF should always be sent stat. No cases of PCN resistant Step pneumo meningitis have been seen in the So. Calif region to date, but if GPC are seen on the gram stain, vanco should be added as a precaution. If dexamethasone is to be given, it should be given before or simultaneous with the first dose of antibiotics. Lastly, CT of brain delays LP. Recommended only if focal neurologic signs, AMS, immunocompromised state or recent seizure. If pt awake, alert, and non focal, CT not indicated.

 

(7)   Remember that this refers ONLY to patients who literally do not have an identifiable source. Those w/abd pain or dysuria or back pain or cellulitis HAVE a potential source and they fall into a different category.