Antibiotic Usage Info

  Aminoglycosides

 

Amikacin (Amikin)

Gentamicin (Garamycin)

Tobramycin (Nebcin)

Cephalosporins (general considerations)

 
Divided into four generations
First generation covers Gram (+) organisms primarily, but also covers E. coli, Proteus, Klebsiella.
Second generation agents have broader spectrum, including Haemophilus influenzae. Two (cefotetan and cefoxitin) have activity against anaerobes including B. fragilis
Third generation possess strong Gram (-) activity.
Ceftazidime (Fortaz, 3rd generation) and Cefepime (Maxipime, 4th generation) have activity against Pseudomonas aeruginosa.
No cephalosporins are active against enterococci.
Safe to use in pregnancy.
Dosage adjustment is required for renal impairment.
Ceftriaxone is eliminated via the biliary tract.
Five cephalosporins cross the blood­brain barrier:

 

Cephalosporins (first generation)

Cephalexin (Keflex)
Appropriate Use
 
Spectrum
Staph and non-enterococcal Strep infections, E. coli, Klebsiella, P. mirabilis.
Precautions
 
Adult Dose
PO 500 mg bid (UTI)
PO 500 mg qid
Cost
$9-18

Cefazolin (Ancef, Kefzol)
Appropriate Use
Pyelonephritis.
Drug of choice for perioperative phophylaxis in surgery not involving the GI or female genital tract.
Spectrum
Staph and non-enterococcal Strep infections, E. coli, Klebsiella, P. mirabilis.
Precautions
 
Adult Dose
0.5-1.0 gm q8h IV or IM.
Prophylaxis
1 gm 30 min prior to surgery and 0.5-1 gm q6h-q8h x 3 doses
Cost
 

Cefadroxil (Duricef)
Appropriate Use
 
Spectrum
Staph and non-enterococcal Strep infections, E. coli, Klebsiella, P. mirabilis.
Precautions
 
Adult Dose
PO 500 mg bid
Cost
$65 / 10d

 

Cephalosporins (second generation)

Cefaclor (Ceclor)
Appropriate Use
Previously promoted for respiratory and ear infections possibly involving H. influenzae.
Now may not be first choice for any indication.
Spectrum
Increasing resistance of H. influenzae and S. pneumoniae becoming an issue.
Precautions
 
Adult Dose
Cefaclor PO 500 mg tid
Ceclor CD PO 500 mg bid
Cost
$90-115 / 10d

Cefuroxime (Ceftin, Kefurox, Zinacef)

Cefpodoxime (Vantin)
Appropriate Use
 
Spectrum
 
Precautions
 
Adult Dose
PO 200 mg bid
Cost
$90 / 10d

Cefprozil

Cefprozil (Cefzil)
Appropriate Use
 
Spectrum
 
Precautions
 
Adult Dose
PO 500 mg bid
Cost
$134 / 10d

Loracarbef

Cefotetan (Cefotan)
Appropriate Use
Mild to moderate infections involving B. fragilis.
Prophylactic use in abdominal, pelvic, colorectal, and C-section surgical procedures.
Spectrum
Enterobacteriaceae, some anaerobes (B. fragilis, Clostridium). More gram neg activity than cefazolin.
Precautions
 
Adult Dose
1-2 gm IV q12h.
1-2 gm deep IM q12h.
Prophylaxis
1-2 gm IV 30-60 min prior to surgery.
Cost
Approximately twice the cost of cefazolin.

Cefoxitin (Mefoxin)
Appropriate Use
Similar to cefotetan, but administered q4-6hr.
Mild to moderate infections involving B. fragilis.
Prophylactic use in abdominal, pelvic, colorectal, and C-section surgical procedures.
Spectrum
Enterobacteriaceae, some anaerobes (B. fragilis, Clostridium). More gram neg activity than cefazolin.
Precautions
 
Adult Dose
1-2 gm IV q4-6h.
1-2 gm deep IM q6h.
Prophylaxis
1-2 gm IV 30 min prior to surgery.
Cost
More costly than cefotetan (because of more frequent dosing).

 

Cephalosporins (third generation)

Cefixime (Suprax)
Appropriate Use
 
Spectrum
Strong Gram (-) activity.
Weakly active against S. pneumoniae.
Adult Dose
 
Cost
 

Ceftibuten (Cedax)
Appropriate Use
Do not use; penicillins are still drug of choice for strep pharyngitis.
Spectrum
Similar to cefixime (Suprax).
Strong Gram (-) activity.
Weakly active against S. pneumoniae.
Not active against Staphylococci.
Adult Dose
PO 400 mg daily.
Cost
$80 for 10 days.

Cefdinir (Omnicef)
Appropriate Use
Indicated for community-acquired pneumonia, chronic bronchitis, acute sinusitis, phyaryngitis, skin infections.
Spectrum
Spectrum similar to cefpodoxime.
Precautions
 
Adult Dose
PO 600 mg qd or 300 mg bid.
Cost
$81 for 10 days.

Cefotaxime (Claforan)
Appropriate Use
Indicated for meningitis in infants and children, life-threatening pneumonia in infants and children and sepsis in neonates (with ampicillin) and children. Also indicated for pneumonia in adults over 40 years, septic arthritis, epiglottitis, gonorrhea and disseminated gonococcal infections and Lyme Disease with carditis.
Spectrum
Primarily active against many gram neg organisms but is active against some gram pos Staph and Strep species.
Adult Dose
IV/IM 1-2 gm q8h.
Gonorrhea: IM 1 gm single dose.
Dose reduction recommended for patients with impaired renal function.
Cost
Approx. 1/3 the cost of a comparable dose of Ceftriaxone and 3/4 that of Ceftazidime

Ceftizoxime (Cefizox)

Ceftriaxone (Rocephin)
Appropriate Use
Indicated for meningitis in both children and adults and life threatening pneumonias. Spectrum similar to Cefotaxime with the advantage of once or twice daily dosing.
Spectrum
Primarily active against gram neg organisms, but some gram pos activity also.
Adult Dose
1-2 gm q12-24h IV or IM
Gonorrhea
250 mg IM single dose
Cost
Approx. 6 times the cost of Cefazolin and 3 times the cost of Cefotaxime and Cefotetan.

Ceftazidime (Fortaz, Tazicef, Tazidime)
Appropriate Use
Indicated primarily in multi-resistant gram neg infections and infections due to P. aeruginosa.
Spectrum
Less gram pos activity than Cefotaxime, similar gram neg activity with better Pseudomonas coverage.
Adult Dose
1 gm q8h IV or IM
Cost
Approx. 10-20% more than Cefotaxime per gram.

Cephalosporins (fourth generation)


Cefepime (Maxipime)
Appropriate Use
 
Spectrum
Active against Pseudomonas, but less so than ceftazidime.
Stronger Gram (+) coverage than 3rd generation agents.
Adult Dose
Parenteral, 1 gm q 12 hr.
Adjust dose for renal function.
Cost
$32 per day.

 

Macrolides


Azithromycin (Zithromax)
Appropriate Use
Used IV as initial therapy of community-acquired pneumonia and PID, followed by oral azithromycin.
Used orally for single-dose treatment of STD's. Advantages are ease of use and improved/observed compliance.
Spectrum
Atypicals. B. burgdorferi.
Precautions
IV: 3-6.5% injection site reaction.
PO: Occasional GI side effects.
Adult Dose
IV: 500 mg daily.
PO: 500 mg day 1, 250 mg days 2-5.
  • Haemophilus ducreyi: 1 gm single dose.
  • Chlamydia: 1 gm single dose.
  • Gonorrhea: 2 gm single dose.
Cost
IV: approx. $18 per day.
PO: $44 for 5 days.
PO: $21 for 1gm single dose.

Clarithromycin (Biaxin)
Appropriate Use
 
Spectrum
Atypicals, Helicobacter pylori.
Precautions
 
Adult Dose
PO: 500 mg bid x 7-10d.
Cost
$66

Erythromycin
Appropriate Use
Can be used in pregnancy for STD treatment.
Spectrum
Atypicals (diphtheria, pertussis)
Precautions
Generally not recommended since less effective and more GI side effects than azithromycin and clarithromycin.

Erythromycin base
Adult Dose
PO: 500 mg qid x 7d.
Cost
$7 /7d

Erythromycin ethylsuccinate (E.E.S., Pediamycin)
Adult Dose
PO: 800 mg qid x 7d.
Cost
$16 /7d

Miscellaneous Agents

Aztreonam (Azactam)
Appropriate Use
Serious infections of skin, lower resp tract, urinary tract with gram (-) organisms.
Abdominal, pelvic, or postoperative infections.
Spectrum
Gram (-) organisms, including Pseudomonas.
Precautions
 
Adult Dose
UTI: IV/IM 0.5-1 gm q8-12h
Systemic infections: IV 1-2 gm q8-12h
Life-threatening infections: IV 2gm q6-8h
Cost
 `

Chloramphenicol (Chloromycetin)

Clindamycin (Cleocin)
Appropriate Use
Gram (+) bacterial infections, including Staph aureus.
Anaerobic infections including Bacteroides fragilis
Treatment of vaginal bacteriosis.
Spectrum
Gram (+) organisms and anaerobes, incl Bacteroides fragilis.
Precautions
Dose does not need to be adjusted in renal dysfunction.
Adult Dose
PO 150-450 mg q6h.
IV 300-900 mg q6-12h.
IM 300-600 mg q6-12h.
Vaginal bacteriosis: 2% cream 5g intravaginally at HS x 7 days.
  Alternative: PO 300mg bid x 7 days.
  Alternative: 100mg vaginal tab at HS x 3 days.
Cost
 

Doxycycline (Vibramycin)
Appropriate Use
Effective for chlamydia, lower cost but more doses than azithromycin.
Suitable for treatment of VRE (vancomycin-resistant enterococci).
Spectrum
 
Precautions
Causes occasional GI problems or photosensitivity.
Contraindicated in pregnancy.
Adult Dose
PO: 100 mg bid x 7 days.
Cost
$8 /7d.

Ertapenem (Invanz)
Appropriate Use
Moderate to severe infections in adults.
Spectrum
Gram (+) and gram (-) infections, aerobic and anaerobic, incl Pseudomonas.
Precautions
Do NOT use in the presence of renal dysfunction.
Adult Dose
IV or IM: 1 gm daily.
Cost
 

Fosfomycin (Monurol)
Appropriate Use
Single-dose treatment of acute uncomplicated UTI in women.
Less effective than 7-10 days of TMP-SMX.
Pregnancy category B.
Diarrhea side effect in 9%.
Spectrum
Effective against E. coli and Enterococcus faecalis but not Pseudomonas.
Adult Dose
PO: 3 gm single-dose packet (orange flavored powder).
Cost
$26 / dose.

Imipenem (Primaxin)
Appropriate Use
 
Spectrum
Gram (+) and gram (-) infections, incl Pseudomonas.
Precautions
Do NOT use in the presence of renal dysfunction.
Adult Dose
 
Cost
 

Linezolid (Zyvox)
Appropriate Use
Indicated for vancomycin-resistant E. faecium and methicillin-resistant Staph. aureus infections.
Spectrum
Similar to vancomycin.
Precautions
Nonselective MAO inhibitor - avoid tyramine in diet.
Potential interaction with serotonergic agents.
Can cause thrombocytopenia in 1-10%. (Check platelet count weekly if used more than 2 weeks.)
Adult Dose
PO 600 mg q12h.
IV 600 mg q12h.
Cost
 

Metronidazole (Flagyl, Flagyl ER)
Appropriate Use
Anaerobic bacterial infections.
Treatment of pelvic inflammatory disease.
Treatment of C. difficile colitis.
Treatment of vaginal bacteriosis.
Treatment of vaginal trichomoniasis.
Treatment of giardiasis and amebiasis.
Spectrum
Anaerobes, incl Bacteroides fragilis.
Garderella vaginalis, Giardia lamblia, Entameba histolytica.
Precautions
Avoid alcohol - causes Antabuse-like effect.
Avoid use in 1st trimester of pregnancy.
Adult Dose
Bacterial infections: PO 500 mg q6-8h x 7-14 days.
Vaginal bacteriosis: PO 2 gm single dose or PO 500 mg bid x 7 days.
Trichomoniasis: PO 2 gm single dose or PO 375-500 mg bid x 7 days or 1 gm bid x 2 doses.
Giardiasis: PO 250 mg tid x 5-7 days or PO 2 gm qd x 3 days.
PID: PO 500 mg bid x 14 days (with another agent).
C. difficile colitis: PO 500 mg tid or 250 mg qid x 7-14 days.
Intestinal amebiasis: PO 750 mg tid x 7-10 days.
Amebic abscess: PO 500-750 mg tid x 7-10 days.
Cost
 

Minocycline (Minocin)
Appropriate Use
Treatment of MSRA (Methicillin-Resistant Staph Aureus), instead of Vancomycin or in addition to Vancomycin.
Treatment of acne vulgaris.
Treatment of gonorrhea and syphilis.
Spectrum
 
Precautions
 
Adult Dose
 
 
Cost
 

Nitrofurantoin (Macrodantin, Macrobid)
Appropriate Use
Prophylaxis and treatment of UTI's.
Spectrum
Active against E. coli, Enterobacter, Klebsiella, and enterococci.
Precautions
Pregnancy category B.
Can cause peripheral neuropathy and pulmonary fibrosis.
Causes brown discoloration of urine.
Don't use in patients with renal insufficiency (Creat. clearance <50 ml/min).
Adult Dose
PO: 50 mg qid (UTI)
PO: 100 mg bid (UTI) (Macrobid)
PO: 50 - 100 mg qHS (prophylaxis)
Cost
$15 for 7 days

Quinupristin / dalfopristin (Synercid)
Appropriate Use
Indicated for IV treatment of bacteremia and life-threatening infections due to vancomycin-resistant Enterococcus faecium. Also indicated for complicated skin and skin structure infections due to Staphylococcus aureus and Streptococcus pyogenes.
Spectrum
Active against E. faeciem but not E. faecalis. Also active against methicillin-sensitive and methicillin-resistant S. aureus and S. epidermidis and penicillin-sensitive and penicillin-resistant Streptococcus pneumoniae. In vitro activity against N. meningitidis, M. catarrhalis, Legionella pneumophila, M. pneumoniae, and C. perfringens.
Adult Dose
For bacteremia, 7.5 mg/kg q8h IV
For skin and skin structure infections, 7.5 mg/kg q12h IV
Cost
Approx. $3000 for 10 day treatment of 65kg patient.

Tetracycline

Trimethoprim (Trimpex)
Appropriate Use
Uncomplicated urinary tract infections.
Urinary tract prophylaxis.
Spectrum
 
Precautions
Generally doesn't cause skin reactions as may happen with TMP/SMX.
Adult Dose
PO 100 mg bid (UTI).
PO 100 mg qHS (prophylaxis).
Cost
Inexpensive.

Trimethoprim / Sulfa (Bactrim, Septra)
Appropriate Use
Prophylaxis and treatment of urinary tract infections.
Penetrates into prostatic fluid, so suitable for prostatitis.
Spectrum
Gram (+) organisms and Gram (-) bacilli.
Does not cover S. pyogenes, enterococci, or Pseudomonas aeruginosa.
Precautions
May cause photosensitivity.
Contraindicated in 3rd trimester of pregnancy.
Adult Dose
PO 80/400 mg qHS (prophylaxis)
PO 160/800 mg q12h
IV 160/800 mg q12h
Cost
Inexpensive.

Vancomycin (Vancocin)
Appropriate Use
Drug of choice for methicillin-resistant Staph aureus.
Can be given PO for C. difficile, but metronidazole is preferred.
Vancomycin is very expensive treatment for C. difficile, reserve for resistant strains.
Spectrum
Gram (+) organisms.
Precautions
 
Adult Dose
IV 1.0 gm q12h
Cost
 

Penicillins

Ampicillin

Appropriate Use
Used IV for treatment of neonatal meningitis to cover Listeria.
Spectrum
 Includes Leptospira, Listeria.
Precautions
Don't use orally; causes more GI effects than amoxicillin.
Adult Dose
 Leptospirosis: 0.5 - 1.0 gm IV q 6 hr
Cost
 

Ampicillin/Sulbactam (Unasyn)
Appropriate Use
 
Spectrum
Gram (+), gram (-), anaerobes.
Precautions
 
Adult Dose
 
Cost
 

Amoxicillin (Amoxil)
Appropriate Use
Drug of choice for acute otitis media.
A CDC recommended regimen for treating chlamydia in pregnancy, but no advantage over other drugs OK for pregnancy.
Spectrum
 
Precautions
 
Adult Dose
PO: 250-500 mg tid x 7d.
PO: 500-875 mg bid.
Cost
$8 /7d

Amoxicillin/Clavulanate (Augmentin)

Oxacillin (trade name)
Appropriate Use
For staphylococcal infections.
Spectrum
 
Precautions
 
Adult Dose
 
Cost
 

Penicillin G
Penicillin G Benzathine (Bicillin LA)
Penicillin V Potassium (Pen VK, V-cillin K, etc.)
Appropriate Use
 
Spectrum
Streptococci, Listeria, Neisseria, Leptospira, anaerobes (except B. fragilis).
Precautions
 
Adult Dose
Leptospirosis: 20-24 million units IV divided q 6 hr. 
Cost
 

Piperacillin (Pipracil)
Appropriate Use
 
Spectrum
Usual penicillin spectrum plus Pseudomonas aeruginosa, Moraxella catarrhalis.
Precautions
 
Adult Dose
IM 2 gm
IV 2-4 gm
Cost
 

Piperacillin/Tazobactam (Zosyn)
Appropriate Use
Beta-lactam inhibitor used for broad coverage including Pseudomonas.
Spectrum
 
Precautions
If given concurrently with an aminoglycoside, separate administration times by at least 30-60 minutes.
Adjust dose for renal insufficiency. For CrCl 20-40 ml/min, decrease dose by 30%. For CrCl < 20 ml/min, decrease dose by 30% and give q 8 hr.
Adult Dose
IV 3.375 gm q 6 hr 
Cost
 

Ticarcillin/Clavulanate (Timentin)
Appropriate Use
Beta-lactam inhibitor used for broad coverage including Pseudomonas.
Spectrum
 
Precautions
 
Adult Dose
 
Cost
 

 

Quinolones (general considerations)

Several generations available.
Initially predominantly gram (-) agents.
Active against Pseudomonas aeruginosa.
Five newer agents have different spectra of activity.
Coverage of Mycoplasma, Chlamydia, and Legionella.
Less active against Pseudomonas.
Active against penicillin-resistant Strep. pneumoniae.
All quinolones are contraindicated in pregnancy or in children.
All are relatively expensive.


Choice of agent by organism:
Pseudomonas
ciprofloxacin
Mycoplasma
levofloxacin
gatifloxacin
moxifloxacin
Chlamydia trachomatis
ofloxacin
N. gonorrhoeae
ciprofloxacin
ofloxacin
Streptococcus pneumoniae
levofloxacin
gatifloxacin
moxifloxacin
are better than ciprofloxacin
Anaerobes
gatifloxacin
moxifloxacin
are better than levofloxacin

UTI treatment
ciprofloxacin
ofloxacin

Safety
ciprofloxacin, ofloxacin, levofloxacin
are safer than gatifloxacin, moxifloxacin
are safer than sparfloxacin
is safer than trovafloxacin

 

Quinolones (first generation)

Nalidixic acid (NegGram)

 

Quinolones (second generation)

Ciprofloxacin (Cipro)
Appropriate Use
Quinolone of choice for Pseudomonas. Also a good choice for prostatitis, gonorrhea.
UTI's if Pseudomonas is a consideration.
Spectrum
Gram (-) organisms.
Precautions
Do not use in pregnancy or pediatrics.
Adult Dose
250-500 mg bid x 7-10 d.
Cost
$70-83 / 10d

Ofloxacin (Floxin)
Appropriate Use
Quinolone of choice for Chlamydia (but no more effective against Chlamydia than azithromycin or doxycycline.
Spectrum
Gram negatives, some atypicals. Ciprofloxacin more effective for Pseudomonas.
Precautions
Contraindicated in pregnancy and in children.
Adult Dose
PO: 200-400 mg bid x 7-10d.
Cost
$80-100 / 10d

 

Quinolones (third generation)


Levofloxacin (Levaquin)
Appropriate Use
Sinusitis, chronic bronchitis, community-acquired pneumonia, skin infections, UTI, acute pyelonephritis.
Spectrum
Narrower coverage than 4th generation quinolones.
Inferior to ciprofloxacin for Pseudomonas.
Precautions
Good safety profile. Do not use in pregnancy or in children.
Dosage or dosing interval needs to be adjusted if renal impairment.
Adult Dose
PO 500 mg qd.
IV 500 mg qd.
Cost
PO $85 for 10 days.
IV $40 per day.

 

Quinolones (fourth generation)

Gatifloxacin (Tequin)
Appropriate Use
Community-acquired pneumonia, chronic bronchitis, acute sinusitis, UTI, pyelonephritis, gonorrhea.
Spectrum
 
Precautions
Potentially a cause of QT prolongation.
Interacts with digoxin and possibly coumadin.
Adult Dose
PO 400 mg qd.
IV 400 mg qd.
Cost
PO $70 for 10 days.
IV $39 per day.

Moxifloxacin (Avalox)
Appropriate Use
Community-acquired pneumonia, chronic bronchitis, acute sinusitis.
Spectrum
 
Precautions
Causes QT interval prolongation.
Dosage adjustment NOT needed for renal impairment.
Adult Dose
PO or IV 400 mg qd for 5-14 days.
Cost
PO: $87 for 10 days.