> ## 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.

# Microdose Radiopharmaceutical Drug Guidance
- URL: https://www.fdaweb.com/microdose-radiopharmaceutical-drug-guidance/
- Published: 2017-09-12T12:00:00.000Z
- Updated: 2026-09-14T22:49:06.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5139599

FDA has published a draft guidance, *Microdose Radiopharmaceutical Diagnostic Drugs: Nonclinical Study Recommendations*, to assist sponsors of microdose radiopharmaceutical drugs on the nonclinical studies recommended to support human clinical trials and marketing applications. The [guidance](https://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM575453.pdf?ref=fdaweb.com) discusses how to refine nonclinical study recommendations for this class of drug given its unique characteristics, such as microdose, radiolabeled, single or infrequent use, clinical use setting, and the agency’s nonclinical and clinical safety experience with the drugs.

The guidance says it also is intended to help sponsors facilitate the timely conduct of clinical trials, reduce the use of animals, and reduce the use of drug development resources. It is intended to provide recommendations for a pathway to full drug development for microdose radiopharmaceutical diagnostic drugs.

“As technology advances,” FDA says, “microdose drugs that use new modalities may emerge. Although this guidance describes recommendations for current radiopharmaceutical diagnostic drugs, the general principles discussed could apply to new diagnostic drugs.”