> ## Content Index
> Fetch the complete content index at: https://www.fdaweb.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# Guidance on Pharmacokinetics in Patients with Impaired Hepatic Function
- URL: https://www.fdaweb.com/guidance-on-pharmacokinetics-in-patients-with-impaired-hepatic-function/
- Published: 2026-09-01T12:00:00.000Z
- Updated: 2026-09-14T12:05:26.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5161716

FDA has released a draft guidance entitled *Pharmacokinetics in Patients with Impaired Hepatic Function: Study Design, Data Analysis, and Impact on Dosage*. The document is intended to assist sponsors in their design and analysis of studies that assess the influence of impaired hepatic function (hepatic impairment (HI)) on the pharmacokinetics and, where appropriate, the pharmacodynamics of a drug.

The [draft guidance](https://www.fda.gov/medical-devices/products-and-medical-procedures/pfas-medical-devices-what-you-need-know?utm%5Fmedium=email&utm%5Fsource=govdelivery) outlines when drug developers should conduct dedicated studies in patients with hepatic impairment, how those studies should be designed and analyzed, and how the findings should be used to develop dosing recommendations. It provides recommendations on the following topics:

- When studies to assess the influence of HI on the pharmacokinetics or pharmacodynamics of a drug should be conducted and when they may not be warranted
- Design and conduct of studies to characterize the effects of HI on the pharmacokinetics of a drug, including the population pharmacokinetic (popPK) approach
- Data analysis and interpretation of these study results, as well as the evaluation of relationships between measures of hepatic function and pharmacokinetic and/or pharmacodynamic parameters

Under the proposed recommendations, FDA says a dedicated pharmacokinetic study generally would be appropriate when hepatic metabolism or excretion accounts for more than 30% of elimination of the absorbed parent drug or active metabolites.

The agency also recommends such studies when relatively small changes in drug concentration could produce clinically important differences in safety or effectiveness, when elimination pathways are poorly understood, or when a drug is likely to be used by people with impaired liver function.

Studies may not be necessary when liver disease is unlikely to change drug exposure enough to warrant a different dose. FDA cites as examples drugs that undergo little hepatic elimination, drugs eliminated entirely through the kidneys, single-use medicines and locally acting products with little or no systemic exposure.