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Is Finasteride Safe? Post-Finasteride Syndrome, and Why It Has Urologists Drawing Battle Lines

Posted by: Men's Health Boston in Men's Health on November 6, 2023

Is Finasteride Safe? Post-Finasteride Syndrome, and Why It Has Urologists Drawing Battle Lines.

Finasteride has received a lot of publicity lately – and not necessarily the good type. The widely prescribed “male-pattern hair loss” medication has increasingly come under fire for associated reports of sexual dysfunction, with purported side effects ranging from erectile dysfunction and loss of sex drive to reduction in penis size and progression of penile curvature. Even more concerning, a growing number of cases link the popular drug to the development of psychological side effects such as depression, anxiety, and suicidal ideation.

But here’s the catch: not everyone agrees that this constellation of associated symptoms, known collectively as Post-Finasteride Syndrome (PFS), is actually real. 

In fact, many prominent researchers and urologists argue against its existence, sparking one of the most notable controversies in the world of modern urology.

So what exactly is PFS, and why is it such a contentious topic?

In keeping with our mission at Men’s Health Boston to provide our patients with first-class medical care and education, today we’ll aim to break down this topic to help you better answer the question, “What are the risks of using Finasteride, and should I be concerned?”

But first, we need to start by diving into the biology behind hormones, hair loss, and healthy prostates…and explaining why Finasteride still has so many advocates.

DHT Giveth, and DHT Taketh Away…

If you paid attention in middle school health class, you’re probably familiar with testosterone as the primary sex hormone defining male characteristics. However, testosterone has a less well-known (but much more potent) cousin known as 5alpha-dihydrotestosterone, or DHT.

DHT is the dominant male sex hormone, or androgen, present in the genitals, prostate, skin, and hair follicles. DHT is produced naturally from testosterone at these sites with the help of a local enzyme known as 5ɑlpha-reductase. (In biology, we often name enzymes after the molecule that they act on. Hence, 5-ɑ-reductase converts testosterone into 5-ɑ-dihydrotestosterone.)

DHT is critically important in differentiating between male and female sex characteristics during periods of rapid growth, such as fetal development during pregnancy, and puberty. However, high DHT is associated with less desirable consequences.

Most notably, a condition known as androgenetic alopecia, or male-pattern hair loss, has been associated with elevated concentrations of 5-ɑ-reductase enzymes and the overactivity of androgen receptors in the hair follicles. This results in higher levels of DHT, which can shrink follicle size and compress the life cycle of hair fibers, ultimately leading to early onset hair loss.

Additionally, it’s thought that elevated DHT levels in the prostate may cause rapid prostate enlargement, a condition known as BPH. While the majority of men will experience some degree of slow prostate enlargement as they age, more severe BPH cases typically impose an assortment of bothersome urinary symptoms, including weak urine stream, straining during urination, urinary urgency and frequency, and incomplete voiding. 

Many men feel left out in the cold when suffering Androgenetic Alopecia and BPH. Neither condition is inherently life threatening, which leads people (medical professionals included) to overlook the very real, very damaging consequences on quality of life, mental health, and self-esteem so often reported by suffering patients.

We therefore cannot stress enough the importance of having viable medical therapies available to these men.

How Does Finasteride Work?

You can think of Finasteride essentially as a supply chain disruptor, developed to combat the negative effects of elevated DHT by cutting off the means of production. The medication is a 5-ɑ-reductase-inhibitor, blocking the action of the critical enzyme that converts testosterone to DHT. This leads to a drop in intracellular DHT concentrations locally in both the hair follicles and the prostate. 

Since the initial clinical trials for FDA approval in 1992, it’s been quite clear that Finasteride effectively reduces prostate size, though this benefit often requires at least 6 months of continuous use to materialize. 

Additionally, numerous studies over the past two decades have reported the efficacy of Finasteride in stemming hair loss, especially in mild-to-moderate cases (of note: if a hair follicle has already died and been overtaken by skin, no amount of DHT suppression will bring it back). See here for published before-and-after photos from one UK-based hair loss clinic.

These are both important truths to acknowledge, because they play into the ferocity of the debate over finasteride use. The now generic medication typically costs less than $20 per month. Finasteride sits at the perfect crossroads of effective and affordable, the holy grail in pharmacologic interventions…but as with most things that sound too good to be true, it very well might be.

Beginning with the earliest studies of Finasteride, there was always a small but reliable potential for sexual dysfunction associated with the drug. 

During the approval process for the treatment of both BPH (1992) and Androgenetic Alopecia (1999), researchers uncovered a similar phenomenon: similar reports of overall adverse side effects between the Finasteride and placebo groups, but a significantly greater risk of sexual dysfunction in the Finasteride group alone. 

However, as noted by the studies’ authors, sexual dysfunction appeared to improve in many cases with continued time on the drug. And in those who didn’t experience eventual relief, the side effects at least subsided when they stopped taking Finasteride.

Post-Finasteride Syndrome: Where the Water Gets Murky…

It’s against this backdrop that many urologists have been speaking out publicly regarding a compilation of seemingly-related phenomena they are witnessing clinically in patients treated with Finasteride. Collectively termed “Post-Finasteride Syndrome” (PFS), these side effects are reported to persist even after treatment is discontinued. Among the reported side effects associated with this label:

Reports of PFS symptoms lasting weeks or months after the drug is stopped have become increasingly prevalent, with a few rare (but terrifying) case studies in which permanent dysfunction is associated with the medication.

However, PFS is not an agreed-upon, established medical diagnosis

In fact, opponents of the Post-Finasteride Syndrome diagnosis point to the large number of early clinical trials which deemed the drug tolerable and safe, with very little evidence of the persistent nature of adverse effects. They claim that ongoing symptoms cannot be adequately explained biologically, given removal of the drug.

Some physicians have even dubbed it a “mystery syndrome”, going as far as to claim that PFS better mirrors a “psychiatric delusional disorder”, stating “…the frequency of consultations for the respective condition parallels the media coverage, which points to a high degree of suggestibility.” (source)

More measured criticisms of the PFS diagnosis argue that the lingering side effects associated with the drug after discontinuation are documented exclusively in lower quality studies with a strong bias in patient selection. It’s also much more common for these reports to emerge from nondermatologists.

However, it’s a universal truth known to practicing clinicians that the drug side effects reported in a few thousand patients in clinical trials is often only a portion of what you will discover when that medication is released to the public and used in hundreds of thousands, if not millions, of people. Because of this, the FDA maintains essential “postmarketing drug surveillance programs” designed to gather continuous data on adverse events associated with medications to identify worrying trends.

And in the case of Finasteride, we believe the cause for concern is warranted.

The Case for Post-Finasteride Syndrome

Whenever we present therapeutic options to our patients at Men’s Health Boston, we always aim to carefully lay out both the potential benefits and risks associated with a given treatment. In a case like Finasteride, with so much widespread disagreement and conflicting data, that can be a tricky needle to thread.

However, our clinical experience with patients who have used Finasteride and reported symptoms of PFS, combined with mounting research evidence that blocking 5-alpha-reductase enzymes may have more systemic effects outside of just the hair and prostate, definitely gives us pause.

In addition to their actions in producing DHT, these enzymes appear to be key in transforming many steroid hormone precursors into active, functional hormones within the central nervous system. In fact, studies have actually demonstrated observable disruption in the concentrations of neurological modulators within the cerebrospinal fluid of patients purporting to suffer from PFS when compared to healthy controls. This lends credence to the claims that Finasteride could cross the blood-brain barrier and potentially affect the mental health of patients. 

In addition, rodent studies have suggested that blocking DHT can actually damage the erectile organ structure and blood flow, causing destruction of smooth muscle cells and increasing collagen deposition in the penis. This does not necessarily mean the same phenomena occur in humans – but it is reason for further investigation.

On its own, biological plausibility (the idea that an effect is possible) is not a very strong case. But with increased documentation of persistent side effects in pharmacovigilance studies, and newer analyses calling into question the adequacy of side effect reporting data in the original trials on Finasteride, we strongly advise a cautious approach to our patients.

Finasteride Complicates Prostate Cancer Screening 

One of the most concerning pieces of evidence against Finasteride use is the revelation that it suppresses prostate-specific antigen (PSA) values.

We’ve written extensively about the use of PSA as a critical tool in monitoring prostate cancer risk for men receiving testosterone replacement therapy. The issue in using a medication which artificially suppresses PSA value is whether or not the monitoring physician is aware of that suppression. It’s quite easy to miss the risk if you aren’t aware of what you are looking at.

(For a deep dive on this topic, listen to prominent prostate cancer urologist Dr. Edward M. Shaeffer, MD, PhD discuss Finasteride and PSA on an episode of popular medical podcast The Drive with Peter Attia.)

Effective Alternatives Exist

As advocates for shared decision-making with patients, MHB believes the determination of whether or not Finasteride is an appropriate treatment belongs to that patient and their urologist. 

However, we strongly advise having a nuanced discussion of the risks versus the benefits of the systemic reduction in DHT, given that in the overwhelming number of cases, effective treatment alternatives DO exist.

The best course for treatment will depend on the individual, their family and medical history, and their appetite for risk.

How Can I Schedule a Consultation?

Living in the shadow of sexual dysfunction and frustration takes a toll on your mental and physical health. And it doesn’t need to be this way. The sooner you seek help, the faster you can get back to having the energy and attention for all of the other important moments life has to offer.

If you or someone you know are suffering, we’re here to help. For more information on our industry-leading care at MHB, click here. For a clinical evaluation, call our office or request an appointment with one of our expert practitioners today.

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