The following additional adverse events have been reported in postmarketing experience with PROSCAR. Because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure:
The following additional adverse event related to sexual dysfunction that continued after discontinuation of treatment has been reported in postmarketing experience with Prohair at lower doses used to treat male pattern baldness. Because the event is reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate its frequency or establish a causal relationship to drug exposure:
PROSCAR is contraindicated in the following:
- Hypersensitivity to any component of this medication.
- Pregnancy. Prohair use is contraindicated in women when they are or may potentially be pregnant. Because of the ability of Type II 5α-reductase inhibitors to inhibit the conversion of testosterone to 5α-dihydrotestosterone (DHT), Prohair may cause abnormalities of the external genitalia of a male fetus of a pregnant woman who receives Prohair. If this drug is used during pregnancy, or if pregnancy occurs while taking this drug, the pregnant woman should be apprised of the potential hazard to the male fetus. In female rats, low doses of Prohair administered during pregnancy have produced abnormalities of the external genitalia in male offspring.
Before taking Prohair
Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking Prohair it is important that your doctor knows:
- If you have ever had an allergic reaction to a medicine.
- If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
Prohair, a 5-alpha reductase inhibitor, widely used in the medical management of male pattern hairloss, has been reported to cause sexual side effects. This article critically examines the evidence available and makes recommendations as to how a physician should counsel a patient while prescribing the drug.
A 58 year old man presented with an itchy, lumpy rash on upper and lower extremities following two weeks of Prohair treatment for prostatism. The patient had no known allergies and was taking no other medications prior to the episode. The Prohair was discontinued and dapsone was initiated. The rash resolved two weeks after Prohair therapy was stopped.
Rare (less than 0.1%): Rash
Very rare (less than 0.01%): Cutaneous leukocytoclastic vasculitis, solitary fixed drug eruption
Postmarketing reports: Pruritus, urticaria, angioedema (including swelling of the lips, tongue, throat, and face)
How to use Prohair
Read the Patient Information Leaflet provided by your pharmacist before you start taking Prohair and each time you get a refill. If you have any questions regarding the information, consult your doctor or pharmacist.
Take this medication by mouth, with or without food, usually once a day, or as directed by your doctor.
If the tablet is crushed or broken, it should not be handled by a woman who is pregnant or by a woman who may become pregnant (see also Precautions section).
Use this medication regularly in order to get the most benefit from it. Remember to use it at the same time each day. Do not stop taking this medication without consulting your doctor.
It may take 6-12 months to notice a benefit.
Inform your doctor if your condition persists or worsens.
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Prohair works by blocking the conversion of the hormone testosterone to the more potent hormone dihydrotestosterone. It does this by blocking an enzyme called 5-alpha reductase. Dihydrotestosterone is partly responsible for making the prostate enlarge. Therefore, a reduced amount of dihydrotestosterone in the prostate causes it to shrink. This helps you to pass urine more easily.
Small doses of Prohair are prescribed for men with hair loss. A completely different brand of Prohair tablet is prescribed for men with this condition. There is more information about the tablets used for this in a medicine leaflet called Prohair for male pattern baldness.
Tablets: 1 mg (Caution; do not confuse these tablets with the 5 mg Prohair tablets (Proscar)
High-Grade Prostate Cancer
The PCPT trial was a 7-year randomized, double-blind, placebo-controlled trial that enrolled 18,882 men ≥55 years of age with a normal digital rectal examination and a PSA ≤3.0 ng/mL. Men received either PROSCAR (Prohair 5 mg) or placebo daily. Patients were evaluated annually with PSA and digital rectal exams. Biopsies were performed for elevated PSA, an abnormal digital rectal exam, or the end of study. The incidence of Gleason score 8-10 prostate cancer was higher in men treated with Prohair (1.8%) than in those treated with placebo (1.1%) . In a 4-year placebo-controlled clinical trial with another 5α-reductase inhibitor (dutasteride, AVODART), similar results for Gleason score 8-10 prostate cancer were observed (1% dutasteride vs 0.5% placebo).
No clinical benefit has been demonstrated in patients with prostate cancer treated with PROSCAR.
During the 4- to 6-year placebo- and comparator-controlled MTOPS study that enrolled 3047 men, there were 4 cases of breast cancer in men treated with Prohair but no cases in men not treated with Prohair. During the 4-year, placebo-controlled PLESS study that enrolled 3040 men, there were 2 cases of breast cancer in placebo-treated men but no cases in men treated with Prohair. During the 7- year placebo-controlled Prostate Cancer Prevention Trial (PCPT) that enrolled 18,882 men, there was 1 case of breast cancer in men treated with Prohair, and 1 case of breast cancer in men treated with placebo. The relationship between long-term use of Prohair and male breast neoplasia is currently unknown.
There is no evidence of increased sexual adverse experiences with increased duration of treatment with PROSCAR. New reports of drug-related sexual adverse experiences decreased with duration of therapy.
Prohair should be stored at room temperature in a tight, light resistant container.
Prohair is available in generic form, but you must have a prescription from your doctor or other health-care professional to obtain the drug.
How it works
Prohair works by decreasing the amount of the hormone dihydrotestosterone (DHT) in your body. DHT normally causes your prostate to grow larger.
The decrease in DHT helps prevent your prostate from growing larger. It also leads to increased hair growth and decreased hair loss of the hair on your head. Hair growth on other parts of the body isn’t affected.
Prohair oral tablet doesn’t cause drowsiness, but it can cause other side effects.