From the FDA Drug Label
- 2 Dosage in Renal Impairment Dosage adjustments of Famotidine are recommended for patients with moderate to severe renal impairment (creatinine clearance less than 60 mL/min) Table 2 shows the recommended maximum dosage of Famotidine 20 mg or 40 mg tablets for patients with renal impairment, by indication. Use the lowest effective dose. Some dosage adjustments may require switching to other formulations of famotidine (e.g., oral suspension, lower dose tablet)
- Dosage reduction is recommended in adult and pediatric patients greater than or equal to 40 kg with moderate or severe renal impairment (creatinine clearance less than 60 mL/minute) 1.
- The recommended maximum dosage of Famotidine for patients with renal impairment is shown in Table 2 1.
- For patients with creatinine clearance 30 to 60 mL/minute, the recommended dosage is 20mg once daily; or 40mg every other day for active duodenal ulcer, and 20mg once daily for symptomatic non-erosive GERD 1.
- For patients with creatinine clearance less than 30 mL/minute, the recommended dosage is 20mg every other day for active duodenal ulcer, and 20mg every other day for symptomatic non-erosive GERD 1.
From the Research
Famotidine requires dose reduction in patients with kidney impairment, with the recommended dose being 20 mg once daily at bedtime or 10 mg twice daily for moderate to severe kidney dysfunction (creatinine clearance less than 50 mL/min). This dose reduction is necessary because famotidine is primarily eliminated by the kidneys, and impaired kidney function leads to drug accumulation and potentially increased side effects 2. The pharmacokinetics of famotidine in patients with renal insufficiency have been studied, and the results indicate that the terminal elimination half-life is prolonged in patients with severe renal insufficiency, and total body clearance and renal clearance are significantly lower in patients with moderate to severe renal insufficiency compared to those with mild renal insufficiency 2. Key points to consider when adjusting the dose of famotidine in patients with kidney impairment include:
- The dose reduction should be based on the patient's creatinine clearance, with a recommended dose of 20 mg once daily at bedtime or 10 mg twice daily for moderate to severe kidney dysfunction (creatinine clearance less than 50 mL/min) 3.
- Patients on dialysis should receive the dose after dialysis sessions.
- Patients with kidney disease may still experience the same therapeutic benefits with these lower doses because the drug remains in the system longer due to decreased clearance.
- Monitor patients for side effects such as headache, dizziness, and constipation, even with adjusted doses.
- Kidney function should be reassessed periodically in patients on long-term famotidine therapy to determine if further dose adjustments are needed 3. It is also important to note that famotidine does not affect creatinine-dependent measurements of renal function and is unlikely to alter the renal elimination of basic drugs 4. However, the most recent and highest quality study on this topic is from 2007, which recommends dosing adjustments based on creatinine clearance or glomerular filtration rate, and using online or electronic calculators to calculate the adjusted dose 3. Therefore, the recommended dose of famotidine in patients with kidney impairment should be adjusted based on the patient's creatinine clearance, and the patient should be monitored for side effects and changes in kidney function.