From the FDA Drug Label
- 1 Central Nervous System Adverse Reactions Central nervous system (CNS) adverse reactions, including confusion, delirium, hallucinations, disorientation, agitation, seizures, and lethargy, have been reported in elderly patients and patients with moderate and severe renal impairment treated with Famotidine Since famotidine blood levels are higher in patients with renal impairment than in patients with normal renal function, dosage adjustments are recommended in patients with renal impairment [see Dosage and Administration (2.2), Clinical Pharmacology (12.3)].
- 6 Renal Impairment CNS adverse reactions and prolonged QT intervals have been reported in patients with moderate and severe renal impairment [see Warnings and Precautions (5.1)]. The clearance of famotidine is reduced in adults with moderate and severe renal impairment compared to adults with normal renal function [see Clinical Pharmacology (12. 3)].
Famotidine and AKI: The FDA drug label does not directly address whether Pepcid (famotidine) will worsen Acute Kidney Injury (AKI). However, it does mention that dosage adjustments are recommended in patients with renal impairment due to higher blood levels of famotidine in these patients 1, 1.
- Key points:
- Higher blood levels of famotidine in patients with renal impairment
- Dosage adjustments recommended in patients with moderate and severe renal impairment
- No direct information on the effect of famotidine on AKI Therefore, it is unclear whether Pepcid will worsen AKI, and a conservative clinical decision would be to exercise caution when using famotidine in patients with renal impairment.
From the Research
Pepcid (famotidine) is not likely to worsen Acute Kidney Injury (AKI) and is considered safer for kidney function compared to proton pump inhibitors (PPIs). The most recent and highest quality study, 2, which compared the risk of worsening kidney function and AKI between PPI initiators and H2-blockers initiators, found that PPIs users presented a reduced risk of AKI compared to ranitidine initiators. Although this study focused on PPIs and H2-blockers, the results suggest that acid-reducing medications like Pepcid, which is an H2-blocker, may have a relatively favorable renal safety profile. Some key points to consider when using Pepcid in patients with AKI include:
- Monitoring kidney function regularly
- Dose adjustment may be necessary in patients with existing severe kidney impairment, as the medication can accumulate
- The standard dosing for adults is typically 20-40 mg once or twice daily, but in patients with creatinine clearance less than 50 mL/min, the dose should be reduced by 50% or the dosing interval extended
- Famotidine works by blocking histamine H2 receptors in the stomach, reducing acid production without directly affecting kidney physiology. It's essential to note that while Pepcid may be safer than PPIs, AKI is a complex condition that requires careful management and monitoring, as highlighted in studies such as 3, 4, and 5.