Finasteride is an oral medication which blocks the conversion of testosterone to dihydrotestosterone
Most modern medical research leans toward the theory that the primary instigator of hair loss is a hormone called Dihydrotestosterone (DHT) which is converted from testosterone and binds to sites on hair follicles. DHT is a hormone formed when the enzyme 5 alpha-reductase interacts with testosterone. DHT is believed to destroy hair follicles in people with hereditary hair loss.
Hair follicles go through three phases of hair production, Anagen, Catagen and Telogen, and DHT appears to make the follicles go into their resting phase faster, which causes the hairs produced by those follicles to become thinner and thinner with each successive growth cycle.
Hair loss is also linked to genetics and hormonal influences. Each hair follicle appears to have a predetermined number of sites to which DHT can attach.
(DHT), the form of the hormone that causes male pattern baldness. It is marketed in the US as Propecia but this is not available in Ireland. Here we often use a generic form of the medication called Fintrid (or Proscar) 5mg. Finasteride inhibits the action of the type II 5-alpha reductase enzyme that is present in higher concentration in and around the hair follicles of balding men with androgenetic alopecia. After two years, results showed that 83% of the men taking Finasteride either kept their hair or grew more. Seventeen percent continued to lose hair while taking the medication.
The medication causes a significant drop in both scalp and blood levels of DHT. Its effectiveness is thought to be related to both of these factors. In patients taking Finasteride 1-mg/day, serum DHT levels decreased by 68.4%. Serum testosterone levels actually increased by 9.1% but remained within the normal range.
Finasteride was originally developed for use in prostate enlargement in men over 50. This medication, in a 5-mg per day dose, is available under the name Proscar.
Many men are concerned about reported sexual side effects with the drug. In truth, the side effect of lower libido was noted in only 1.8% of the men taking the drug in clinical trials, versus 1.3% on a placebo. Further, this side effect always went away in men who stopped taking Propecia, and also disappeared in most men who continued taking Propecia.
Most reported cases of sexual dysfunction occurred soon after the medication was begun. The sexual side effects were reversible in all men who discontinued therapy and in 58% of those who chose to continue treatment. When the medication was stopped, side effects generally went away within weeks, but occasionally took longer.
It is important to remember that when Finasteride (or Minoxidil) is discontinued, you only lose the hair that was gained or preserved by the medication, not more. In effect, you return to the level of balding where you would have been had you never used the drugs in the first place.
Finasteride in sport
The World Anti-Doping Agency (WADA) removed Finasteride from its list of banned substances in October 2008. It had previously been added as it was believed that Finasteride could be used to mask the use of steroids and other drugs. This is no longer believed to be the case and you can read more about WADA and its decision here. We would however still advise you to consult your sport’s governing body before taking Finasteride.
Effects on PSA
Finasteride causes an approximate 1/3 decrease in serum PSA (prostate specific antigen) in normal men (from 0.78ng/ml to 0.52 ng/ml). It may also blunt the rise of PSA levels in patients with prostate enlargement and in patients who have developed prostate cancer.
Since PSA is used as a screening test for the development of prostate cancer there is a concern that the use of Propecia may interfere with the detection of this disease. It is important that your family doctor is aware that you are taking Finasteride so that he can take into account any effects that Finasteride may have on your PSA. It is possible that the long term use of Propecia may actually decrease the incidence of prostate disease, but this has not yet been confirmed in scientific studies. A recent study suggested a possible 25% reduction in prostate cancer.
Long-term benefits and risks
The effects of Finasteride are confined to areas of the scalp that are thinning, but where there is still some hair present. It does not seem to grow hair in areas that are completely bald. Therefore, the major benefit of Finasteride seems to be in its ability to slow down or stop hair loss, or regrow hair in parts of the scalp that are thin. The long-term ability of Finasteride to maintain one’s hair is unknown. Results generally peak around one year and then are stable in the second year or decrease very slightly.
Propecia and hair transplantation
Propecia (Finasteride) has been shown to be a useful addition to surgical hair restoration for a number of reasons. Propecia works best in the younger patient who may not yet be a candidate for hair transplantation. Propecia is less effective in the front part of the scalp, the area where surgical hair restoration can offer the greatest cosmetic improvement. Propecia can regrow, or stabilize hair loss, in the crown where hair transplantation may not always be indicated.
If Propecia is shown to be safe and effective in the long-term, it will afford the hair restoration surgeon the ability of creating more density in the most important areas cosmetically (such as the front part of the scalp), thus keeping donor reserves for future hair loss in other areas.
An estimated 1 million men in the United States take Propecia daily. Most men taking Propecia experienced an increase in hair count, a decrease in hair loss, and an improvement in appearance. It is important, however, to have realistic expectations, as results take time. If you are not willing to commit yourself to taking Finasteride for at least 12 months, it’s probably not worth starting. Secondly, Finasteride must be taken on an ongoing basis to maintain the benefit.
The manufacturer states that any hair grown or maintained by Propecia will be lost within 12 months if the patient stops taking the medication. In addition, men who are already very bald are less likely to benefit from Propecia, because the hair follicles may not be salvageable. Men who have early thinning in the back and top have a better chance to see some benefit, but as noted above, only for as long as they continue taking the medication.
Proscar – important information about pregnancy
As outlined above, the type II 5-alpha reductase inhibitor Finasteride in Proscar and Propecia works by inhibiting the conversion of testosterone to dihydrotestosterone. This makes this chemical extremely useful in treating male pattern baldness. However, because of this ability to affect testosterone, exposure to Finasteride could have the potential to cause abnormalities in the sexual organs of male foetuses.
For this reason, women should not take or handle Proscar or Propecia tablets when they are or may become pregnant. Therefore, although Proscar tablets are specially coated to prevent any contact with the active ingredients, women are advised not to handle tablets, especially broken or crushed tables, as there is a potential for Finasteride to be absorbed through the skin and into the bloodstream.
Questions have been raised as to whether women who are pregnant or trying to conceive are at any risk if their partner is taking Proscar or Propecia. To date, animal studies on pregnant monkeys using intravenous doses as high as 800ng/day (which is up to 120 times the highest estimated exposure of women to Finasteride from the semen of men taking 5mg/day) resulted in no abnormalities at all. However, for peace of mind, to prevent even this tiny theoretical risk, men who are concerned can either stop taking the drug or use condoms to prevent any possible Finasteride exposure during pregnancy.
Dutasteride, a second-generation 5-alpha-reductase inhibitor, is the first medicine to inhibit both the type 1 and type 2 enzymes responsible for the conversion of testosterone to DHT (dihydrotestosterone), the primary cause of prostate growth. Dutasteride’s dual inhibition decreases levels of DHT by 90% at 2 weeks and 93% at 2 years. To date, it has not been approved for the treatment of male pattern baldness.
A study by Elise Olsen et al. published in the Journal of the American Academy of Dermatology, demonstrated that Dutasteride increased scalp hair growth, and the results from Dutasteride 2.5mg were superior to the results from Finasteride 5mg at 12 and 24 weeks. The study included over 400 male subjects over 24 weeks and compared the results achieved by 0.05mg, 0.1mg, 0.5mg and 2.5mg Dutasteride, 5mg Finasteride, and placebo tablets daily. For further information, please see the Journal of the American Academy of Dermatology Vol 55 Issue 6, Pages 1014-1023 December 2006.
Update on Finasteride
Objective overview of the medications approved by the FDA in the United States and other state medical treatment licensing agencies throughout the world, used in the prevention and treatment of androgenic hair loss (male pattern baldness).
Medications are used both in the management of early hair loss and in conjunction with hair transplantation for the treatment of the more advanced stages of this condition. Indeed, some hair surgeons would consider their use a mandatory adjunct to surgical hair transplantation.
It is generally felt that these treatments are more effective in the 18-41 age group, but exceptions exist and significant benefits from these medications are frequently seen outside this age group.
The most efficacious of these medications is Finasteride which was originally approved for treatment of benign enlargement of the prostate gland in 1992 and subsequently licensed for the treatment of male pattern hair loss in December 1997. Its mechanism of action in both conditions is identical, the inhibition of Type II 5-alpha reductase, an intra-cellular enzyme that converts testosterone to 5-alpha dihydrotestosterone (DHT). Both benign enlargement of the prostate and male hair loss is dependent on the presence of this hormone, which although vital in the genital development of the male foetus, does not appear to have a critical role in the adult male.
Finasteride has been extensively studied. An EBSCO-host search of the literature show that 21,924 papers have been produced on this medication since its introduction, 2,373 of these being published since January 2010 (14th October 2011). These studies have extensively evaluated the efficacy and the safety of this agent and as a result of this research, Finasteride has been established as an important, potent and safe treatment of both male pattern baldness and benign prostatic hypertrophy and some other conditions.
The great majority of users do not suffer any side effects from its use. Less than 2% of males report decreased libido, semen volume and erection difficulties which disappear on stopping Finasteride and usually also resolve on continuing to use it. Recently, a very small number of users report persistence of the sexual difficulties. The PCPT prostate trial which looked at the sexual dysfunction in 17,313 patients, taking Finasteride over a 7 year period, found that Finasteride caused only a small average increase in sexual dysfunction that decreased over time. The anecdotal reports of prolonged sexual difficulties, however, have been criticized for their selection and recall bias and lack of psychological evaluation of the patients and the failure to out-rule the very many other causes of these symptoms.
The total freedom of 97% of Finasteride users from any side effects whatsoever lead us to the conclusion that other factors are involved in the genesis of these persistent sexual symptoms. Erectile dysfunction (ED) is the most thoroughly studied sexual dysfunction in men and the most common sexual complaint of men presenting to their health care providers. Various large-scale studies (both cross-sectional and longitudinal) have indicated that the worldwide prevalence of ED is between 10% and 20%. ED is strongly correlated with aging, with a steep incline in prevalence rates, from 6.5% in men aged 20 to 39 years to 77.5% in those aged 75 years and older. ED is also associated with various co-morbidities, including psychological factors, cardiovascular diseases, diabetes mellitus, and metabolic syndrome, and with smoking.
Finasteride has been investigated over a number years as a chemo-preventative for prostate cancer. Two major trails have been undertaken. The statistical results are currently difficult to interpret as some forms of prostate cancer are reduced and a smaller fraction of higher grade cancers appear to be increased in incidence. The latter may be due to the Finasteride reducing the prostate size and consequently increasing the likelihood of a positive biopsy hit in the reduced target gland. Notwithstanding the difficulties involved in the interpretation of these studies and despite the lack of FDA approval for its use as a chemo-preventative, many leading prostate surgeons are suggesting the use of Finasteride to patients who are at high risk of developing prostate cancer as might be suggested by a very strong family history and also in those who have been shown to have pre-cancerous conditions of the prostate diagnosed on biopsy.
The association between Finasteride use and the development of breast cancer is mentioned in the side effect data sheet. No statistical data exists to substantiate an increased incidence of breast cancer in users of Finasteride and the association is purely theoretical. This speculative risk has led clinicians to advise users to check for breast lumps which all males should do in any event as the total world incidence of male breast cancer is increasing possibly due to the rising levels of environmental oestrogenic chemicals. The rare, non-cancerous enlargement of the male breast (gynecomastia) associated with Finasteride as well as many other prescribed and recreational drugs as well as food stuffs is not regarded as a pre-cancerous condition.
Depression has recently been observed in patients taking Finasteride. The incidence of this is very low, amounting to a small fraction of the very significant total incidence of depression associated with untreated hair loss.
Other side effects of Finasteride are also mentioned in the side effect data sheet. These are likely to represent symptoms resulting from the rare allergy to the medication as they are commonly associated with allergic reactions to other medications, environmental chemicals and food stuffs.
To put the above in context, our use of and regular monitoring of patients taking Finasteride over 8 years shows that over 97% of users experienced no side effects whatsoever from this medication.
To advise patients not to use this treatment would not only put ourselves out of line with scientifically based, ethically motivated hair clinics throughout the world but to deny our patients an opportunity to choose an important and effective treatment for their hair loss, a condition frequently associated with loss of self esteem, quality of life and psychological discomfort. As ethical medical practitioners, we need to follow and be guided by peer reviewed mainstream clinical and scientific studies published in major international journals rather than the internet blogs and chat rooms many of whom have other agenda.
MB, BCh, FRCS RCPS Glasg,FRCS Edin,FRCS Eng,FRCSI.