From the FDA Drug Label
Cephalexin should be administered with caution in the presence of markedly impaired renal function. Under such conditions, careful clinical observation and laboratory studies should be made because safe dosage may be lower than that usually recommended.
Keflex kidney dosing requires caution in patients with markedly impaired renal function. The dosage may need to be lower than usual, and patients should be closely monitored with careful clinical observation and laboratory studies 1.
From the Research
Keflex (cephalexin) dosing should be adjusted in patients with kidney impairment to prevent drug accumulation and potential toxicity, with the most recent and highest quality study 2 emphasizing the importance of accurately assessing renal function and determining the influence of renal replacement therapy on antibiotic clearance. For adults with normal kidney function, the standard dose is 250-500 mg every 6 hours. However, in renal impairment, the following adjustments are recommended:
- For mild to moderate impairment (creatinine clearance 10-50 mL/min), give the usual dose every 8-12 hours;
- For severe impairment (creatinine clearance less than 10 mL/min), give the usual dose every 12-24 hours. Patients on hemodialysis should receive a dose after each dialysis session. These adjustments are necessary because Keflex is primarily eliminated through the kidneys, and reduced kidney function leads to drug accumulation and potential toxicity, as noted in earlier studies 3, 4, 5, 6. Monitoring for side effects such as nausea, diarrhea, and allergic reactions is important, especially in patients with kidney disease. Serum creatinine and estimated glomerular filtration rate (eGFR) should be checked before starting therapy to determine the appropriate dosing regimen. Adequate hydration should be maintained during treatment to support kidney function. It is also crucial to consider the pharmacodynamic profile of the antibiotic and the operating characteristics of the renal replacement therapy when determining the dosing strategy, as highlighted in the most recent study 2. Therapeutic drug monitoring should occur when possible, along with careful monitoring for antibiotic efficacy and safety.