From the FDA Drug Label
Renal Impairment Penicillin G is relatively nontoxic, and dosage adjustments are generally required only in cases of severe renal impairment. The recommended dosage regimens are as follows: Creatinine clearance less than 10 mL/min/1. 73 m2; administer a full loading dose (see recommended dosages in the tables above) followed by one-half of the loading dose every 8 to 10 hours. Uremic patients with a creatinine clearance greater than 10 mL/min/1. 73m2; administer a full loading dose (see recommended dosages in the tables above) followed by one-half of the loading dose every 4 to 5 hours.
The recommended dose for benzyl penicillin (Penicillin G) in patients with impaired renal function is as follows:
- For creatinine clearance less than 10 mL/min/1.73 m2: administer a full loading dose followed by one-half of the loading dose every 8 to 10 hours.
- For uremic patients with a creatinine clearance greater than 10 mL/min/1.73 m2: administer a full loading dose followed by one-half of the loading dose every 4 to 5 hours. Key points:
- Dosage adjustments are required only in cases of severe renal impairment.
- The dosage of penicillin G should be reduced in patients with severe renal impairment, with additional modifications when hepatic disease accompanies the renal impairment 1.
From the Research
For patients with impaired renal function, benzyl penicillin (Penicillin G) dosing should be adjusted based on creatinine clearance (CrCl), with a recommended dose of 3 million units as a loading dose, followed by continuous infusion of 10 to 12 million units every 12 hours, adjusted according to the formula: dose (mu/24 h = 4+[creatinine clearance divided by 7]) 2.
Key Considerations
- In mild to moderate renal impairment (CrCl 10-50 mL/min), the standard dose can be given every 8-12 hours instead of every 4-6 hours.
- In severe renal impairment (CrCl <10 mL/min), the dose should be reduced by 25-50% of the normal dose and administered every 12-18 hours.
- For patients on hemodialysis, a supplemental dose should be given after each dialysis session as penicillin G is removed by dialysis.
Rationale
- Penicillin G is primarily eliminated by the kidneys, so reduced renal function leads to drug accumulation and potential neurotoxicity if doses aren't adjusted 2.
- Symptoms of toxicity include confusion, seizures, and myoclonus.
- Regular assessment of renal function and clinical response is essential during treatment.
Supporting Evidence
- A study published in Chest in 1997 provides guidance on penicillin dosing for pneumococcal pneumonia, including adjustments for renal impairment 2.
- While other studies provide information on penicillin pharmacokinetics and dosing, the 1997 study is the most relevant and recent guidance for adjusting benzyl penicillin doses in patients with impaired renal function.