Finasteride (marketed under the brand names
Propecia® and
Proscar®) is a prescription medicine that has been licensed for the following uses:
- Treatment of male pattern baldness.
- Treatment of enlarged prostate. An enlarged prostate is also known medically as benign prostatic hyperplasia, benign prostatic hypertrophy, or BPH.
Brand-name finasteride (Proscar or Propecia) is manufactured by Merck & Co., Inc.
Generic finasteride is made by several manufacturers.
Finasteride works by blocking the conversion of testosterone into DHT (dihydrotestosterone), which decreases the amount of DHT in the body. Since DHT is important for enlargement of the prostate, using finasteride to decrease DHT levels can treat an enlarged prostate. The medication helps to shrink the prostate in most men, helping with their BPH symptoms.
DHT is also important for male pattern baldness. By decreasing the amount of DHT, the medication can help stop hair loss and regrow hair.
There have been several studies looking at how well finasteride treats an
enlarged prostate. In particular, there has been one very large study that studied several of the effects of finasteride for men with
BPH, with the following results:
Symptoms of BPH
The men in this study were asked to rate the following symptoms of BPH:
- Decreased size and force of urine stream
- Feeling of incomplete bladder emptying when urinating
- Delayed or interrupted urination
- Having to get up to urinate frequently during the night
- Having to urinate frequently during the day
- Needing to strain or push the flow of urine.
The men who took finasteride had significant improvement in their BPH symptoms compared to the men who did not take finasteride. While some patients saw improvement right away, in general, it took about six months to see the improvement for most men. This improvement lasted throughout the entire study period (four years).
Acute Urinary Retention
This study also looked at how many men had acute urinary retention. If an enlarged prostate is very severe, a man may not be able to urinate at all. This is known medically as acute urinary retention and usually requires catheterization (inserting a small tube through the penis into the bladder in order to empty the urine). Of the men who took finasteride, 2.8 percent had acute urinary retention that required catheterization, compared to 6.6 percent of men who did not take finasteride.
Surgery
In this study, 4.6 percent of men who took finasteride needed to have BPH surgery, while 10.1 percent of men who did not take finasteride needed to have surgery.
Urine Flow
Men who took finasteride had an improvement in the rate of urine flow. This increased flow rate was seen as early as the fourth month after starting finasteride and continued throughout the entire study.
Effectiveness for Male Pattern Baldness
There have been several studies looking at how well the medication treats male pattern baldness.
Male Baldness
One study looked at using finasteride for vertex male pattern baldness (hair loss at the very top of the head) in men. At first, the men who took finasteride had new hair growth, while the men who did not take finasteride continued to lose hair. After about a year, the increase in new hair growth stopped for the men on finasteride, and these men started to slowly lose their hair again. However, the hair loss was much slower for the men taking finasteride than for the men who were not taking finasteride.
After five years of taking finasteride, 48 percent of men had increased hair growth, 42 percent had no change (the hair loss had stopped), and 10 percent had lost hair. For the men who were not on finasteride, 75 percent had lost hair after five years.
In a study looking at finasteride for hair loss treatment near the front of the head (in the center) in men, finasteride was effective in increasing hair growth. This study did not include men with hair loss near the temples.
Female Hair Loss
A small study looked at finasteride for postmenopausal women with female pattern baldness. This study did not show a difference for the women who took finasteride. This could mean that the medication is not effective for female hair loss, or it could mean that the study did not include enough women to be able to notice a difference.
When and How to Take Finasteride
Some general considerations for when and how to take the medication include:
- Finasteride comes in tablet form. It is taken by mouth once daily.
- It may take as long as three months to see results for hair loss with this drug and as long as six months to see results for BPH.
- It can be taken with or without food.
- It should be taken at the same time each day to maintain an even level of the drug in your blood.
- For the medication to work properly, it must be taken as prescribed. It will not work if you stop taking it. If you are taking finasteride for male pattern baldness, hair loss will return within one year after you stop taking it.
The dosage depends on which condition is being treated. The doses of finasteride are:
- BPH -- finasteride 5 mg daily
- Male pattern baldness -- finasteride 1 mg daily.
As with any medication, do not adjust your dose unless your healthcare provider specifically instructs you to do so.
Side Effects of Finasteride
As with any medicine, there are possible side effects. However, not everyone who takes the medicine will experience side effects. In fact, most people tolerate finasteride well. When side effects do occur, they are often minor and either require no treatment or can easily be treated by you or your healthcare provider. Serious side effects are less common.
The most common side effects of finasteride include:
(Click Finasteride Side Effects to learn about the specific side effects of this drug, including serious side effects to look out for.)
You can also read about other possible side effects by going to the following eMedTV articles:
There are no known drug interactions with finasteride.
What Should I Tell My Healthcare Provider?
You should talk with your healthcare provider before taking finasteride if you have:
- Liver disease or liver failure, including cirrhosis
- Any allergies, including allergies to foods, dyes, or preservatives.
Also, let your healthcare provider know if you:
Tell your healthcare provider about all other medicines you may be taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.
Overdose With Finasteride
In studies, large doses of finasteride did not cause any overdose symptoms.
If you happen to overdose, or if you are a pregnant woman who has taken finasteride, seek medical attention immediately.
The medication should be stored at room temperature away from moisture or heat. Finasteride tablets should be kept in an airtight container. Because this drug is so dangerous for pregnant women, women should not touch broken or crushed finasteride tablets if they are pregnant or may be pregnant.
Keep finasteride and all medications out of the reach of children.
What Should I Do If I Miss a Dose?
If you do not take your finasteride as scheduled, take your next dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take a double dose.
Finasteride tablets are available in two strengths:
- Finasteride 1 mg tablets (generic for Propecia)
- Finasteride 5 mg tablets (generic for Proscar).
While Proscar and Propecia cannot be used interchangeably, some healthcare providers may recommend cutting the 5 mg tablets in quarters to use instead of the 1 mg tablets
(see Propecia and Proscar for more information).
For the 5 mg strength, both brand-name and generic finasteride are licensed and available for sale. For the 1 mg strength, both brand-name and generic versions are licensed, but the generic version is not yet available in pharmacies.
