- Type of Drug: Alpha-reductase inhibitor.
- Prescribed for: Benign prostatic hypertrophy (BPH). Finasteride has also been studied as therapy following radical prostatectomy surgery and for the prevention of first-stage prostate cancer, male pattern baldness, acne, and unusual hairiness.
Finasteride (Proscar) General Information
Progressive enlargement of the prostate gland generally occurs in men over age 50 and is associated with a gradual reduction in urine flow. (The number of men affected by BPH increases with advancing age.) Finasteride works by interfering with the action of the enzyme alpha-reductase, which is essential in the process of converting testosterone into a much more potent androgenic substance called 5α-dihydrotestosterone (DHT). A single 5-mg dose of Finasteride produces a rapid drop in DHT levels, with the maximum reduction occurring 8 hours after taking the dose. DHT levels remain low for 24 hours and stay low as long as the drug is continued. Six to 12 months of Finasteride treatment may be needed to assess its effect.
There is no way to predict who will respond and who will not. In a clinical study of Finasteride, men experienced a significant regression in prostate size after 3: months, a reduction that was maintained throughout the 12-month study period. Also, study subjects experienced a significant improvement in urine flow. Extended studies showed that these improvements could be maintained up to 36 months.
Finasteride (Proscar) Cautions and Warnings
Do not take Finasteride if you are allergic to any component of the product. This drug is not meant to be taken by women or children.
Finasteride only works in BPH. Other conditions that can mimic BPH, such as infection, prostate cancer, bladder or nerve disorders, or physical obstruction of the urinary tubes, will not be improved by this medicine.
Finasteride must be used with caution by people with liver disease, because that is where it is broken down in the body.
Animal studies have shown that Finasteride may increase the chance of testicular cancer and reduce male fertility. Finasteride may mask prostate cancer by causing a reduction
In the level of prostate-specific antigen (PSA), an increasingly acknowledged indicator of prostate cancer. While a low PSA level-does not necessarily exclude the possibility of prostate cancer, a higher one is definitely cause for further investigation.
Possible Side Effects
Finasteride side effects are generally mild and well tolerated.
- Most common: impotence, loss of sex drive, and decreased amount of semen.
Finasteride (Proscar) Drug Interactions
Finasteride increases the rate at which Theophylline and Aminophylline are broken down in the liver. These changes may not affect the amount of Theophylline or Aminophylline you need to control your asthma.
You may take this drug with food if it upsets your stomach.
Adult and Senior: 5 mg once per day.
Woman and Child: do not use.
Finasteride (Proscar) Overdosage
People have taken single doses up to 400 mg and daily doses up to 80 mg for 3 months without any side effects. In animal studies, the drug was lethal at doses equal to 182 to 455 mg per pound of body weight. Call your local poison control center or hospital emergency room for more information. If you go to a hospital for treatment, ALWAYS bring the medicine bottle.
Crushed Finasteride tablets should not be handled by women who are, or might become, pregnant because small amounts of the drug could be absorbed into the blood, possibly affecting a developing fetus.
If your sexual partner is, or may become, pregnant and you start taking this medicine, you must wear a condom to avoid directly exposing her to Finasteride-containing semen. Other options are to avoid sexual contact or stop the drug.
Semen volume may be decreased while on Finasteride, but this should not interfere with normal sexual function. Impotence or reduced sex drive is a possibility.
If you forget to take a dose of Finasteride, take it as soon as you remember. If it is almost time for your next dose, skip the forgotten dose and continue with your regular schedule. Do not take a double dose. Call your doctor if you forget to take this medicine for 2 or more days.
Finasteride (Proscar) Special Populations
Pregnant or nursing women must not take this drug because of the harm it could cause (see Cautions and Warnings).
Seniors retain Finasteride in their bodies longer, but dosage adjustment is not required, nor is dose adjustment needed in people with kidney disease.