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Pharmacokinetics
| Indication
& Dosage | Action
| Interaction
Adverse
Effect & Precautions |
Brands available in Market
Pharmacokinetics
Finasteride is absorbed following
oral administration, and peak plasma concentrations are achieved in 1 to
2 hours. The mean bioavailability has variously been reported as 63% and
80%. It is about 90% bound to plasma protein. Finasteride is metabolised
in the liver and excreted in urine and faeces as metabolites. Mean
half-life is 6 hours in patients under 60 years of age but may be
prolonged to about 8 hours in those 70 years of age or older.
Indication
& Dosage
Oral
SYMPTOMATIC BENIGN PROSTATIC
HYPERPLASIA: 5mg once daily. 6-12 months therapy may be necessary in
some patients before a beneficial effect is seen. No dose adjustment
required in patients with renal impairment.
Action
Competetive inhibitor of
the enzyme 5-alpha reducates which converts testosterone to
dihydrotestosterone (DHT). It has no affinity for androgen
receptors. Cnoversion of testosterone to DHT by 5 alpha reductase is
essential for prostatic hyperplasia. Finasteride has no significant
effect on circulating levels of several hormones. the hypothalamus-hypophysis-gonad
axis is not affected
Interaction
Theophylline increased
theophylline clearance and decreased its half life.
Adverse
Effect & Precaution
Increased libido, breast tenderness,
impotence and hypersenitivity reactions.
Precaution: Hepatic dysfunction, patients with large residual urine
volume, increase in PSA level.
Man: May be used
