Finasteride for Hair Loss | What you need to know

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In discussing treatment options with patients for male pattern baldness, after topical options, an oral medication called Finasteride known by the trade name Propecia is often considered. Before prescribing this finasteride, I have a discussion with each patient to ensure that they are fully informed of the risks and benefits associated with taking this medication.

What is the connection between finasteride, prostate cancer, and PSA?

Prostate cancer is the most common solid organ cancer in men and the second most common cause of cancer death in men. The PSA or prostate-specific antigen blood test is used to screen for prostate cancer in addition to digital rectal exams. Finasteride is used in doses of 5mg to treat benign prostatic hyperplasia and 1mg daily to treat male pattern baldness. It works by blocking an enzyme called 5 alpha-reductase that converts testosterone to dihydrotestosterone.

A large study in 2006 showed that men taking Finasteride had a lower risk of developing prostate cancer overall, however, when they did develop prostate cancer it tended to be a higher risk of a higher grade prostate cancer. Finasteride can decrease the PSA levels on blood tests by about 50%. There was a study in 2019 that demonstrated that the use of finasteride may delay prostate biopsies, show worse pathology, and increase the mortality associated with prostate cancer.

For these reasons, I ask my patients that take Finasteride to disclose this to their primary care doctors to avoid misinterpreting the PSA level on screening tests. The PSA may need to be doubled to reflect an accurate interpretation in the setting of taking finasteride. A study in 2007 confirmed that even though the dosage of 5mg daily for BPH was originally studied for this recommendation, the 1mg dosing used for male pattern baldness also demonstrated lower PSA levels.

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Given the effect on PSA, is finasteride considered safe?

From a PSA perspective, Finasteride is considered overall safe and effective to treat and manage male pattern baldness with the appropriate monitoring in place. As long as the patient and their primary care physician understand that the PSA level needs to be adjusted and that prostate cancer screening should include digital rectal examinations as well, these potential challenges can be managed. Also, it is important to recognize that any trends that indicate the PSA is increasing over time even if still in the normal range should be referred for further evaluation.

Are there any other side effects associated with finasteride to be aware of?

Now onto the other side effects noted with Finasteride. I advise patients that there are some reversible and some potentially irreversible side effects associated with taking Finasteride.

Libido disorders, ejaculation disorders, and orgasm disorders are potential adverse effects that may be reversible after discontinuation of the medication however there is the potential for these to be irreversible side effects and persist even after discontinuation of the medication. The potentially irreversible nature of these side effects led the FDA to revise the label in 2012 to reflect this post-marketing experience.

In addition, there are reports of male infertility and/or poor semen quality. These side effects are thought to normalize or improve after stopping the medication.

After presenting this information to patients, the response to whether or not to start therapy varies in my experience based on the age of the patient and the stage of hair loss they have reached. Mild hair loss in younger patients may lead to the decision to use topical minoxidil as maintenance and to consider oral therapy if needed at a later time. If a patient is concerned about these potential effects but, would like to consider other options beyond topical therapy, we can consider PRP injections or hair transplants. A detailed discussion of each to determine where each patient is in terms of expectations and desired outcomes helps guide patients to make the best decision for them.

Can women take finasteride?

Finasteride use in women has increased over the past several years. It has been used to manage female androgenetic alopecia (female pattern hair loss), frontal fibrosing alopecia, lichen planopilaris, and hirsutism with varying levels of success. Some studies suggest that it may have fewer side effects than alternative options such as spironolactone. And, it has also been suggested that if women start at an older age prior to losing a significant volume of hair, they may have a better response.