Scientific Review of Adverse Effects (AE) of Finasteride and Dutasteride
Results Abstract:
Reported AEs with 5ARIs include sexual dysfunction, infertility, mood disorders, gynecomastia, high-grade prostate cancer, breast cancer, and cardiovascular morbidity/risk factors, although their true association, prevalence, causality, and clinical significance remain unclear. A pooled summary of all randomized, placebo-controlled trials evaluating 5ARIs (N = 62,827) revealed slightly increased rates over placebo for decreased libido (1.5%), erectile dysfunction (ED) (1.6%), ejaculatory dysfunction (EjD) (3.4%), and gynecomastia (1.3%). The limited data available on the impact of 5ARIs on mood disorders demonstrate statistically significant (although clinically minimal) differences in rates of depression and/or anxiety. Similarly, there are limited reports of reversible, diminished fertility among susceptible individuals. Post-marketing surveillance reports have questioned the actual prevalence of AEs associated with 5ARI use and suggest the possibility of persistent symptoms after drug discontinuation. Well-designed studies evaluating these reports are needed.
This is from a new review of the available data, published in Sexual Medical Reviews, titled “Side Effects of 5-Alpha Reductase Inhibitors: A Comprehensive Review“.
The report concluded: “5ARIs are associated with slightly increased rates of decreased libido, ED, EjD, gynecomastia, depression, and/or anxiety. Further studies directed at identifying prevalence rates and persistence of symptoms beyond drug discontinuation are required to assess causality.”
Indeed, I look forward to reading more controlled studies that are necessary to determine the relationship between the cause and effect.
This is a well done review. While adverse event reports (“side effects”) in individuals taking drugs are required to be made to the FDA during a clinical trial (and after marketing) independent of causality – this adds to a better understanding of the possible incidence of these events (although underreporting can occur). As Dr R notes, well-controlled studies are needed to better define the causative factors of these events.
This publication basically says finasteride affects several pathways in ways they we do not yet fully understand. If you look at the official website or marketing literature for Propecia you will see that Propecia inhibits the conversion of T to DHT. But it is also accepted that finasteride inhibits the production of allopregnanolone, THDOC and androstane diol and others.
The first two can be crudely labeled ‘brain chemicals’ which many consumers are unknowingly altering when they take Propecia. It is reckless and dishonest for doctors to prescribe these drugs without warning patients they are tweaking ‘brain chemicals’ that are not yet understood.
We will likely never get a chance to test these effects in a controlled experiment since it would require a prohibitively large population and budget, invasive testing techniques, and IRB approval. But this doesn’t mean that consumers are guaranteed safety and they should be made aware of the risks and uncertainties they face.
This is very worrying Dr.Rassman. Should we assume that propecia should not be used long term or at all until properly controlled studies can be conducted?
In the past, Dr. Rassman has not directly mentioned these effects of taking finasteride and has only alluded to them on a few occasions. I think the best thing you can do for yourself is to familiarize yourself with research has been done on the potential long-term side effects of Propecia. Realize this is a not well understood area of modern medicine and these effects are reported infrequently. Then make a thoughtful decision for yourself. It may be worth it for you depending on how much you care about your hair, sex life, and your personal comfort with risk-taking.
This is a personal decision for everybody and what upsets me so much is that many hair transplant surgeons skip the informed consent which effectively makes a decision for them. Just remember this is about hair loss (not even a medical condition), not a cancer treatment, and the powerful nature of the drug should be respected accordingly.