Finasteride marketed as Propecia®

Finasteride is marketed by Merck under the trademark names Proscar® and Propecia®, among other generic names.  It is a synthetic antiandrogen that inhibits type II 5-alpha reductase, the enzyme that converts testosterone to DHT.  Only available by prescription, it was developed to treat mild to moderate male pattern hair loss on the vertex (top of head) and anterior mid-scalp area (middle front of head) in men only. There is insufficient evidence that Propecia® works for receding hairlines at the temples.  Listed side effects include erectile dysfunction and depression.  Once treatment is stopped, all results will be lost within 6 to 12 months.



GENERIC NAME: finasteride tablets

BRAND NAME: Propecia (for male hair growth)

DRUG CLASS AND MECHANISM: Finasteride is a synthetic compound that is used for the treatment of male pattern hair loss or androgenetic alopecia in males only. Finasteride blocks conversion of testosterone to dihydrotestosterone (DHT). Finasteride decreases the blood and scalp concentrations of DHT which is thought to be associated with androgenetic alopecia.
Propecia® (1 mg finasteride) was approved by the FDA for the treatment of male pattern baldness in December 1997. Another finasteride oral dosage form, Proscar® or 5 mg finasteride tablets are FDA approved only for the treatment of benign prostatic hyperplasia (BPH) and should not be used for androgenetic alopecia. Do not confuse these finasteride tablets.



Side affects of Finasteride - Propecia®


Hit the market in Dec 1997

Hitting the market in Dec 1997, Propecia® was known as a sort of miracle drug. The drug was more effective at combating hair loss than Rogaine and was not a messy topical application. Although, pharmaceutical manufacturer Merck warned that a small percentage of all Propecia® users could experience problems with erections and decreased libido. However, to the millions of people who turned to Propecia to prevent their hair loss, it was well worth the risk.


Research indicates long lasting side effects

Fast forward to 2014, where research has shown that Merck may have underestimated the persistence of some of Propecia's side effects. As part of a study published in a June 2011 issue of the Journal of Sexual Medicine, Dr. Michael Irwig of George Washington University surveyed 71 regular Propecia users and noted that 94 percent suffered low libido, 92 percent experienced erectile dysfunction, and 92 percent had decreased sexual arousal. Increasingly alarming, the survey indicated that some side effects could last an average of 40 months after patients discontinued use of the drug, going against the commonly held perception that the cure for any unwanted symptom is simply to stop taking the pill. "That's the novelty of this study – the persistent side effects of Propecia," Irwig says.


Did Merck now of side effects?

Although the sample size of Irwig's study was small and that most of the men he interviewed were recruited from an online support group, The percentage of users who suffer significant side effects is undoubtedly smaller than this study suggests. However, there's little reservation that these findings will attract more examination in the future. Of course, they have already attracted lawyers: Several firms across North America are currently pursuing cases against Merck. The key inquiry now is whether Merck knew that side effects could persist even after patients stopped taking the drug. In response to some inquiries, Merck has acknowledged that some Propecia users – it put the number at 1.3 percent – experienced erectile dysfunction, but the company remains evasive on the subject of how long side effects can last, saying "a causal relationship...has not been established."


To understand the link between hair growth and sexual function, it helps to know how the drug works. Finasteride, the active compound in Propecia, is a 5-alpha reductase inhibitor, meaning it blocks the conversion of testosterone to the more potent dihydrotestosterone (DHT), which thins hair and contributes to baldness. Finasteride was originally developed to shrink enlarged prostates (in a drug called Proscar), but doctors noticed that it also grew hair. It is important to understand that infant males born without the ability to convert testosterone to DHT are also born with ambiguous genitalia. "You need DHT to make a penis," Irwig explains. For this reason, pregnant women are told to avoid exposure to the drug. Some individuals who have taken Propecia for hair growth didn’t bother to read the accompanying label and are now finding that their side effects have gotten worse after stopping the medication, although many admit that it did stop hair loss. The question to consider is, it is worth it? Meanwhile, the FDA has been relatively quiet on this matter.