Finasteride is an azasteroid that inhibits the type-2 isoform of 5?-reductase, the enzyme responsible for conversion of testosterone to the more active dihydrotestosterone, and therefore has anti-androgenic properties. It is given by mouth in a dose of 5 mg daily in the management of benign prostatic hyperplasia to cause regression of the enlarged prostate and to improve symptoms; it may reduce the incidence of acute urinary retention and the need for surgery. Response may be delayed and treatment for 6 months or more may be required to assess whether benefit has been achieved.
In the treatment of male-pattern baldness (alopecia androgenetica) in men, finasteride is given by mouth in a dose of 1 mg daily. In general, use for 3 months or more is required before benefit is seen, and effects are reversed within 12 months of ceasing therapy.
Precautions of Using Finasteride in Kenya
Finasteride should be used with caution in hepatic impairment in Kenya. When used for benign prostatic hyperplasia, finasteride should be used with caution in men at risk of obstructive uropathy. Patients should be evaluated for prostatic carcinoma before and during therapy. Use of finasteride decreases concentrations of serum markers of prostate cancer such as prostate specific antigen (PSA) by up to 50% even when cancer is present, and reference values should be adjusted accordingly; the ratio of free to total PSA (percent free PSA) remains constant.
Studies in animals suggest finasteride could produce feminisation (hypospadia) of a male fetus if used in pregnant women; therefore, its use is contra-indicated in women who are or may become pregnant. In addition, it is recommended that women in this category should not handle crushed or broken finasteride tablets. Finasteride has been detected in semen, therefore use of a condom is recommended if the patient’s sexual partner is, or may become, pregnant.
Adverse Effects of Finasteride
The most commonly reported adverse effects of finasteride are decreased libido, impotence, ejaculation disorders, and reduced volume of ejaculate. Breast tenderness and enlargement (gynaecomastia) may occur, and there have been reports of hypersensitivity reactions such as swelling of the lips and face, pruritus, urticaria, and rashes. Testicular pain has also been reported.