Adverse events of 5-alpha-reductase inhibitors

I've taken 5-alpha-reductase inhibitor drugs and am suffering lasting side- effects. What should I do?

Please talk to your doctor about the specific symptoms you're experiencing. If you're currently taking a 5-alpha-reductase inhibitor drug, discuss your concerns about the medication. Ask your doctor about other treatment options for managing your condition.

Also, we recommend that you submit your symptoms to your nation's drug regulatory agency. In the United States, it is the FDA. Reporting of adverse events and medication errors is voluntary. The MedWatch site provides information about voluntary reporting.

People outside the US can find a list of international reporting agencies at the following link to the World Health Organization's Uppsala Monitoring Centre:

Currently, there is very limited information in the medical literature to guide treatment of symptoms that may occur in association with 5-alpha- reductase inhibitor use. There is little data to help a person anticipate what may be in the future in regards to their symptoms. Discuss the possible risks and benefits of your treatment given possible side effects. If you experience what you see as side effects, talk to your primary care provider about appropriate referrals to specialists, such as endocrinologists, urologists, or psychologists who may be able to address your individual symptoms.

The following study is underway to learn more about the relationship between 5-alpha-reductase inhibitors and erectile dysfunction, other sexual dysfunction (ejaculatory and psychosexual dysfunction, low libido, Peyronie's disease), breast outcomes, and depression. Researchers will also investigate the persistence of symptoms and risk factors for such persistence. Click on the study title below to visit the NIH RePORTer and read the study summary. The RePORTer is a NIH tool that has information on all NIH-funded research activities.


Patient advocacy groups are another source for learning more about clinical research opportunities. You can check the Post-Finasteride Syndrome Foundation Web site for information on PFS Research Initiatives.

While we are not aware of a clinical research study enrolling people with adverse events from taking 5 alpha-reductase inhibitors at this time, you can periodically check the Research section of this Web page for updates. You can also consider joining a patient research registry. Patient registries collect and organize health information. They help researchers design new studies and find people who might want to participate.

ResearchMatch is a free national research registry designed to bring together patients, healthy volunteers and researchers. ResearchMatch was developed by major academic institutions across the country and is funded by the National Center for Advancing Translational Sciences, NIH.

Last updated on 05-01-20

Clinical Research Resources

RePORTER Post Finasteride syndrome

The Research Portfolio Online Reporting Tool (RePORT) provides access to reports, data, and analyses of research activities at the National Institutes of Health (NIH), including information on NIH expenditures and the results of NIH-supported research. There is a study titled AN EPIDEMIOLOGIC EVALUATION OF ADVERSE EVENTS OF 5-ALPHA-REDUCTASE INHIBITORS that may be of interest to you. Click on the study title to learn more.

Last updated on 04-27-20

Where To Start

Post-Finasteride Syndrome Foundation

The Post-Finasteride Syndrome Foundation provides information on this condition, including a listing of symptoms reported in association with the use of 5-alpha-reductase inhibitors.

Last updated on 04-27-20

FDA 5 alpha reductase inhibitors

The US Food and Drug Administration provides safety information on 5-alpha reductase inhibitors.

Last updated on 04-27-20

Name: Post-Finasteride Syndrome Foundation 27 World’s Fair Drive
Somerset, NJ, 08873,
Email: Url:

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