penicillin G aqueous (Pfizerpen, penicillin G potassium, penicillin G sodium, Crystapen)
Classes: Penicillins, Natural
Dosing and uses of Pfizerpen, penicillin G potassium (penicillin G aqueous)
Adult dosage forms and strengths
premixed injectable solution
- 1 million units/50mL
- 2 million units/50mL
- 3 million units/50mL
potassium, powder for injectable solution
- 5 million units/vial
- 20 million units/vial
sodium, powder for injectable solution
- 5 million units/vial
Meningococcal Meningitis/Septicemia
20-30 million units/day IV continuous infusion x14 days or afebrile x7days, Or
200,000-300,000 units/kg/day IV divided q2-4hr x24 doses
Actinomycosis
Cervicofacial cases: 1-6 million units/day IV
Thoracic and abdominal disease: 10-20 million units/day IV divided q4-6hr x 6 weeks, may follow with penicillin V
Botulism
Adjunctive to antitoxin: 20 million units/day IV divided q4-6hr
Vincent’s Infection (fusospirochetosis)
5-10 million units/day IV divided q4-6hr
Rat-Bite Fever
Indicated for Streptobacillus moniliformis and Spirillum minus (rat-bite fever)
12-20 million units/day IV divided q4-6hr x3-4 weeks
Listeria Infections
Meningitis: 15-20 million units/day IV divided q4-6hr x2 weeks
Endocarditis: 15-20 million units/day IV divided q4-6hr x4 weeks
Pasteurella Infections
Bacteremia or meningitis: 4-6 million units/day IV divided q4-6hr x2 weeks
Erysipeloid
Endocarditis: 12-20 million units/day IV divided q4-6hr x4-6 weeks
Diphtheria
Adjunct to antitoxin or to prevent carrier state: 2-3 million units/day IV divided q4-6hr x10-12 days
Anthrax
Minimum: 5 million units/day IV
12-20 million units/day IV have been used
Streptococcal Infections
Empyema, pneumonia, pericarditis, endocarditis, meningitis: 5-24 million units/day IV divided q4-6hr
Syphilis
Neurosyphilis: 18-24 million units/day IV x10-14 days
Streptococcal Group B Infection
Prophylaxis: 5 million units IV at the onset of labor or after membrane rupture followed by 2.5 million units IV q4hr until delivery
Lyme Disease (Off-label)
200,000-300,000 units/kg/day IV x 10-14 days
Renal Impairment
CrCl 10-50 mL/min: Decrease dose by 25%
CrCl <10 mL/min: Decrease dose by 50-70%
Hemodialysis: Removed by hemodialysis; administer after dialysis
Pediatric dosage forms and strengths
premixed injectable solution
- 1 million units/50mL
- 2 million units/50mL
- 3 million units/50mL
potassium, powder for injectable solution
- 5 million units/vial
- 20 million units/vial
sodium, powder for injectable solution
- 5 million units/vial
Neonatal Bacterial Infection General Dosing Guidlines
<7 days & <2000 g: 50,000 units/kg/day IV divided q12hr
<7 days & >2000 g: 75,000 units/kg/day IV divided q8hr
>7 days & <1200 g: 50,000 units/kg/day IV divided q12hr
>7 days & 1200-2000 g: 75,000 units/kg/day IV divided q8hr
>7 days & >2000 g: 100,000 units/kg/day IV divided q6hr
Infant & Children Bacterial Infection General Dosing Guidelines
Moderate Infection: 25,000-50,000 units/kg/day IV/IM divided q6hr
Severe Infection: 250,000-400,000 units/kg/day IV/IM divided q4-6hr
Not to exceed 24 million units/day
Meningitis
Neonates <7 days & <2000 g: 100,000 units/kg/day IV divided q12hr
Neonates <7 days & >2000 g: 150,000 units/kg/day IV divided q8hr
Neonates >7 days & <1200 g: 100,000 units/kg/day IV divided q12hr
Neonates >7 days & 1200-2000 g: 150,000 units/kg/day IV divided q8hr
Neonates >7 days & >2000 g: 200,000 units/kg/day IV divided q6hr
Infants & Children: 250,000-400,000 units/kg/day IV divided q4hr; not to exceed 24 million units/day
Group B Streptococcal Meningitis
Neonates <7 days: 250,000-450,000 units/kg/day IV divided q8hr
Neonates >7 days: 450,000 units/kg/day IV divided q6hr
Congenital Syphilis
Neonates <7 days: 100,000 units/kg/day IV divided q12hr
Neonates >7 days: 150,000 units/kg/day IV divided q8hr
Endocarditis
Infants and Children <45 kg: 250,000 units/kg/day IV divided q4hr
Pfizerpen, penicillin G potassium (penicillin G aqueous) adverse (side) effects
Frequency not defined
Seizure
Anemia
Interstitial nephritis
Hypersensitivity
Anaphylaxis
Jarisch-Herxheimer reaction
Positive Coombs' reaction
Warnings
Contraindications
Allergy to penicillins, cephalosporins, imipenem
Cautions
Renal/hepatic impairment: reduce dose based on severity of impairment
Clostridium difficile associated with diarrhea (CDAD) ranging from mild diarrhea to fatal colitis; may occur over 2 months after the administration of antibacterial agents; may need to discontinue penicillin if CDAD is suspected or confirmed
Pregnancy and lactation
Pregnancy category: B
Lactation: excreted in breast milk
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Pfizerpen, penicillin G potassium (penicillin G aqueous)
Half-Life: 20-50 min (ESRD 3-5 hr)
Peak Plasma Time: IM 30 min, IV 1 hr
Protein Bound: 65%
Distribution: crosses placenta, poor blood brain barrier diffusion
Metabolism: hepatic to active metabolites
Excretion: urine
Mechanism of action
Interferes with synthesis of cell wall mucopeptide during active multiplication, resulting in bactericidal activity against susceptible microorganisms.
Administration
IV Incompatibilities
Additive: floxacillin, quinidine
Syringe: heparin
Y-site: aminophylline, cefamandole, cefazolin(?), heparin, Na bicarB
IV Compatibilities
Additive: dobutamine, lidocaine, KCl, procainamide, propafenone, verapamiL
Y-site: cefazolin(?), clarithromycin, dobutamine, dopamine, erythromycin, gentamicin, lidocaine, morphine, norepinephrine, KCl, vancomycin
IV Preparation
Rapid loading: 150 mg/100 mL D5W (1.5 mg/mL)
Slow infusions: 900 mg/500 mL D5W (1.8 mg/mL)
IV Administration
If infusion >2 hr: use glass or polyolefin bottles
