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Antimicrobials

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Penicillin

Guidelines for use

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1. Clinical Uses

  • Treatment of the following infections caused by susceptible organisms (usually streptococci):
    •  Bacteremia, Endocarditis, Meningitis, Osteomyelitis, Pharyngitis (streptococcal), Skin and soft tissue infections, Syphilis
  • Prophylaxis of perinatal group B streptococcal (GBS) disease
  • Prophylaxis of infective endocarditis associated with certain procedures

2. Precautions

  • The potential for cross-reactivity exists among penicillins, cephalosporins and carbapenems.
  • Beta-lactamase resistance in gram-negative rods may develop during therapy with ceftriaxone
  • Pregnancy: not expected to increase risk of major congenital malformations
  • Breastfeeding: considered safe during breastfeeding. Monitor nursing infant for GI symptoms.

3. Adverse Effects

  • Nausea, abdominal pain, vomiting, diarrhea
  • Skin rash
  • Hypersensitivity reactions including anaphylaxis
  • Phlebitis at site of IV infusion
  • Rarely: interstitial nephritis; blood dyscrasias; elevated liver enzymes; seizures (drug accumulation in renal insufficiency)

4. Dosage

Penicillin G Sodium IV Therapy: ("MU" = "million units")

  • Bacteremia, Endocarditis, Meningitis, Neurosyphilis, Osteomyelitis: 4 MU IV q4h
  • Skin and soft tissue infections: 2 MU IV q4 - 6h
  • Intrapartum prophylaxis of perinatal GBS disease: 5 MU IV x 1; then 2.5 MU IV q4h until delivery
  • Renal insufficiency: See table below

Penicillin VK Oral:

  • Usual dosage for minor infections: 300 - 600 mg PO q6h
  • No reduction required for renal insufficiency
  • 300 mg penicillin VK = 500,000 IU
  • Oral bioavailability = 60% (taken on an empty stomach)

Penicillin G Benzathine IM:

  • Primary, secondary, or early latent syphilis: 2.4 MU IM x 1 dose
  • Latent (late or unknown duration) or tertiary syphilis: 2.4 MU IM once weekly x 3 doses
  • Penicillin G benzathine (Bicillin L-A) is a long-acting depot IM injection that is supplied by Toronto Public Health. Contact Pharmacy to coordinate procurement for inpatient use.

Renal Insufficiency:

CREATININE CLEARANCE (mL/min) IV PENICILLIN G DOSAGE
10 to 29 Max 16 MU/day (e.g., 4 MU IV q6h)
< 10 or PD Max 12 MU/day (e.g., 4 MU IV q8h)
Hemodialysis (HD)

Max 12 MU/day (e.g., 4 MU IV q8h)

On dialysis days, give one of the day's doses towards the end of HD.
Continuous Renal Replacement Therapy (CRRT)

Usual Dosing

5. Administration

(for IV Penicillin G Sodium):
  • Intermittent Infusion: infuse over 30 - 60 minutes
  • Continuous Infusion: 4 MU IV q4h each dose infused over 4h
    Please refer to IV drug monograph on pharmacy intranet page for additional administration information.