A 1mg tablet preparation of finasteride has been licensed as a prescription only medicine for the treatment of male pattern hair loss. The product, called Propecia, has not yet been launched by its manufacturer, Merck Sharp & Dohme (MSD).
Propecia is licensed to increase hair growth and prevent further loss of hair in the treatment of male pattern hair loss. The drug is not indicated in women.
MSD says that it is in discussion with the Department of Health about the product's prescription status. A spokeswoman for MSD told The Journal on October 25 that the company would prefer the drug to be available only on private prescription but the decision regarding its classification was for the Government. According to MSD, the Secretary of State is expected to consult advisory committees before deciding whether Propecia should be categorised in Schedule 10 or 11 of the NHS (General Medical Services) Regulations 1992. Schedule 10 drugs (the "black list") may only be supplied on private, and not NHS, prescriptions. Schedule 11 drugs can be supplied on NHS prescriptions but only for defined conditions.
Finasteride, at a higher 5mg strength, is currently used to treat benign prostatic hyperplasia. Dr Julian Cole (medical affairs director, MSD) told The Journal on October 26 that MSD did not expect Propecia to cause any prostate problems. There were "marginal" decreases in levels of serum prostate-specific antigen (PSA) but these were not "relevant". (PSA increases with prostate size and is elevated in prostate cancer.) Dr Cole said that there was "no issue" of treatment with Propecia masking the diagnosis of prostate cancer through its effects on PSA levels.
Finasteride inhibits type II 5-alpha-reductase enzyme. This inhibition blocks the peripheral conversion of testosterone to dihydrotestosterone (DHT). Hair follicles contain type II 5-alpha-reductase. Increased levels of DHT result in miniaturisation of hair follicles which is seen in the bald areas of men with male pattern hair loss. Hair loss is not seen in men with a genetic deficiency of type II 5-alpha-reductase. MSD says that these factors suggest a link between male pattern baldness and the presence of DHT. Finasteride is reported to cause a rapid decrease in levels of DHT, producing a significant response within 24 hours.
Taking finasteride can stop further hair loss and, in some cases, allow re-growth of hair, the company says. It reports that in phase III clinical trials involving 1,879 men with mild to moderate hair loss, 86 per cent of men treated with finasteride 1mg daily for 12 months either maintained or showed an increase in the number of hairs on their head. At 24 months, dermatologists rated 66 per cent of those treated with Propecia to have increased hair growth compared with only 7 per cent of the control group. MSD says that the hair grown as a result of treatment with Propecia is normal and not downy. It adds that an improvement of the quality of hair was seen in year two of treatment, according to photographic and patient assessment.
The prescribing information for the drug notes that a small number of men have experienced minor side effects including decreased libido and erectile dysfunction (reported in less than 1 per cent of men). These effects are usually reversible on stopping treatment and sometimes stop when treatment is continued. The drug is reported to have no effect on the growth of body hair.
MSD says that once daily treatment for three to six months is required before evidence of stabilisation of hair loss can be seen. If treatment is stopped, the beneficial effects begin to reverse after six months and return to baseline by nine to 12 months. Treatment should be started when hair thinning has become apparent and would not be of use in men with severe hair loss.
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Hair growth at baseline (left), after one year of treatment with Propecia (centre) and after two years treatment (right) |