Category: Drugs

This blog entry was written by Bernard P. Nusbaum, MD, and posted with his permission.

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Finasteride, which is the generic name for Propecia, has been approved for the treatment of Male Pattern Hair Loss since 1998. Finasteride works by inhibiting the enzyme ,5 alpha reductase type II, that forms DHT. There has been a lot of interest by both patients and physicians in dutasteride, which is a drug that inhibits both type I and type II 5 alpha reductase enzyme.Dutasteride is three times more potent than finasteride inhibiting the type II enzyme and 100 times more potent than finasteride inhibiting the type I form of the DHT producing enzyme. Dutasteride is not approved by the FDA for the treatment of Male Pattern Hair Loss and is approved at a dose of 0.5 mg a day for the treatment of prostate enlargement. While both the type I and type II enzymes are found in the hair follicle, there is a recent study which shows that type I is present in the human brain.The function of this enzyme in the brain is still unclear.

The most extensive study of dutasteride in the treatment of male pattern hair loss was published by Olsen and others in the Journal of the American Academy of Dermatology in December of 2006. This was a randomized, placebo-controlled study of 416 men for a 24 week treatment period. The study evaluated various doses of dutasteride versus 5 mg of finasteride versus placebo. At the time of the study the 1 mg finasteride dose (Propecia) was not commercially available, but the comparison is valid since the effects on hair growth of 5 mg. 1 mg. of finasteride are equal.

The results of the study were as follows: Hair counts in the vertex showed that only dutasteride at a dose of 2.5 mg a day (which is five times the dose approved for prostate enlargement) was better than finasteride at 12 and 24 weeks. When an expert panel evaluated photographs before and after treatment, the 2.5 mg dose was better than finasteride at 12 weeks and both the 0.5 and 2.5 mg doses were better than finasteride at 24 weeks — in other words, dutasteride at a 2.5 mg daily dose worked faster than 0.5 mg .

Scalp DHT suppression, which is felt to be correlated to a drug’s effectiveness, was measured and showed that finasteride decreased scalp DHT by 32%, dutasteride 0.5 mg by 51% and dutasteride 2.5 mg showed 79% suppression. DHT concentration in the blood was decreased 73% by finasteride, 92% by dutasteride 0.5mg. and 96% by dutasteride 2.5 mg . The speed by which drugs are eliminated from the body are measured by a value which is called “half-life”. The half-life of finasteride is six to eight hours whereas for dutasteride it is four to five weeks, which means that when one stops taking dutasteride, it will take several months before the drug is out of the system. When blood DHT was measured in these patients 12 weeks after stopping the medication, the finasteride treated patients had a normal DHT level while the dutasteride 0.5 still showed a 10% decrease and the dutasteride 2.5 mg treated patients still had significantly lowered DHT levels.

Sexual side effects were determined and, although there were no statistically significant differences between placebo, finasteride and dutasteride, it is noteworthy that in the patients treated with 2.5 mg dutasteride daily, 13% complained of decreased libido. As has been the experience with finasteride, half of these patients experienced resolution of their side effects despite continuing to take the medication. The other 50% had to stop the treatment in order for side effects to subside.

Side effects of dutasteride which have been reported in the treatment of prostatic enlargement are 1) breast tenderness and enlargement, and 2) reduced sperm counts. In a separate study of 28 patients treated with dutasteride 0.5 mg daily there was a significant decrease in sperm count at 26 weeks of treatment. That study states that it is difficult to determine the significance of these sperm count abnormalities and that the reports vary as to what sperm counts are required for fertility. It is quite concerning that two of the 28 patients in the study had a greater than 90% decrease in sperm count while taking the medication and 24 weeks after stopping the drug, they still had a 70% reduction in sperm count. Although the study did not give figures on the percentage of patients that developed sperm count abnormalities, this side effect, in my opinion, is worrisome especially since we commonly treat young men for male pattern hair loss. It should be noted that finasteride 1 mg (Propecia) was shown in a separate study to have no effect on sperm count.

In conclusion, dutasteride improved hair growth in male pattern hair loss more rapidly and to a greater degree than finasteride at a dose of 2.5 mg per day which is five times the dose approved for prostate enlargement. Dutasteride is approved by the FDA for the treatment of prostatic enlargement at a dose of 0.5 mg per day and there is insufficient safety data on higher doses. Dutasteride is NOT approved by the FDA for the treatment of Male Pattern Hair Loss and patients should be informed about the benefits versus the possible adverse effects. Finasteride 1 mg (Propecia) has been shown to stop the progression of male pattern baldness in 90% of the patients treated with the drug. It has an excellent safety profile with only 2% of patients experiencing decreased sex drive and no reports of sperm count abnormalities.

We are currently awaiting the results of a phase III study being conducted in Korea to evaluate dutasteride 0.5 mg daily in the treatment of male pattern hair loss.

Dr. Rassman,

I have read on your blog that .5 mg of propecia once daily is believed to be 80% as effective as the recommended dosage of 1 mg.

With that being said, in your clinical practice, are you aware of any patients showing clinical or measurable improvement when taking only a .5 mg dosage of propecia once a day? In other words, what are your experiences in practice with taking this minimal dosage due to side effects?

Most of my patients take the recommended 1mg of finasteride. There are a minority of patients who take 0.5mg of finasteride, because they’ve reported side effects or believe they just want to be on a maintenance regimen. While the 0.5mg dose is not an approved dose for hair loss, the reports show it is 70 to 80% as effective as the full 1mg dose. This is difficult to impossible for me to verify, though. To answer your question more specifically, I would need access to the studies done when the dose when optimized by Merck. I don’t have enough experience with the 1/2 dose to tell you more.

I understand that blocking DHT can help prevent hair loss. When I read the ingredients in alot of products that help prevent hair loss, they claim to reduce testosterone. Is reduction of testosterone safe? How does that effect the libido? Is reducing DHT the same as reducing testosterone and I’ve just misunderstood?

In adults, DHT (dihydrotestosterone) plays its greatest role in mediating the testosterone effect in hair follicles (essentially causing hair loss in genetic hair loss conditions), and in bringing on nose and ear hair. It also plays a role in producing prostatic swelling and some feel it plays a role in causing prostate cancer in those people genetically prone to it.

Reducing DHT is not the same as reducing testosterone. In fact, if you reduce DHT, you may get a very slight transient increase in testosterone. There may be products that claim to, or actually do reduce testosterone levels, but none are approved for the treatment of hair loss. In any case, use caution and be sure to consult your physician prior to use.

If you want to get into the bio-chemical details: testosterone is converted to DHT by the enzyme 5-alpha reductase. Finasteride (Propecia), the only FDA approved oral hair loss drug, works by blocking this enzyme, effectively decreasing the amount of DHT, thus decreasing hair loss. Testosterone can still act on other tissues without being converted to DHT.

Thank you Dr. Rassman for this incredibly helpful blog. It seems that the internet is FULL of snake-oil salesmen for men losing their hair, and your site is one of the few truly helpful sites.

My question:
I’m a younger man (25) and started using rogaine foam about 9 months ago at the first sign of my hairline receding. The rogaine did not help this, and my hairline continued to recede, so I finally spoke with my doctor and he gave me an Rx for Propecia which I have been taking for 2 weeks. My question is whether I should continue to use the Rogaine with the Propecia and what I what you have seen these (or just one) of these products have effect on the temple region.

Thanks!

Rogaine sometimes develops dependencies, but I can not tell you if you have developed them. I suspect not, just because you did not see a benefit. Nevertheless, I would continue the Propecia for 8 months, until most of the benefits from finasteride has been reached. If there are benefits from Propecia and you should stop it, you will lose all benefits fairly quickly. Both of these products will reduce hair loss, but Propecia is more certain in male genetic hair loss. Although it does happen on rare occasion, neither, I suspect, will regrow the frontal hair.

nice site. my question is i would like to go on propecia but i take an anti blood pressure pill in the morining and a depression pill around dinner time, is it safe to take propecia along with these drugs and when should i take propecia along with these drugs ?

thank you.

You should take the finasteride whenever you can remember to take it (no more than the daily recommend dosage, however). I would hope that you take your Propecia once a day and your blood pressure and antidepressant pills when they are scheduled.

What are the sever allergic reactions some people have to propecia? I have taken propecia for 2 years and then stopped for 3 years. I just started taking again, is it possible for me to have a severe allergic reaction after having no troubles the 1st time? I am not choking or having a reaction or anything, just curious.

A severe allergic reactive would be, as your describe, choking and throat swelling that could lead to death. Many drugs and foods can cause allergic reactions, but I have never heard of the aforementioned severe reaction with finasteride (Propecia/Proscar). The most common side effects of Propecia are:

1. increase or decrease in sex drive
2. decrease in fluid ejaculate at orgasm
3. breast tenderness

These side effects are reversible if you stop taking the medication, as the finasteride only lasts in your blood stream for about a day.