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1mg Tablet
A tan octagonal convex tablet embossed with a P logo on one side and PROPECIA
on the other.
Diameter: 7.14mm.
PROPECIA (finasteride, MSD) is a synthetic 4-azasteroid compound that is a specific inhibitor of type II 5α-reductase , an intracellular enzyme that metabolises the androgen testosterone into dihydrotestosterone (DHT)
The recommended dosage is one 1-mg tablet daily. PROPECIA may be taken with or without food.
|In general, daily use for 3 months or more is necessary before increased hair growth and/or prevention of further hair loss is observed. Continued use is recommended to obtain maximum benefit. Withdrawal from the treatment leads to reversibility of effect within 12 months.
In clinical studies with PROPECIA in men 18-41 years of age, the mean value of serum prostate-specific antigen (PSA) decreased from 0.7 ng/mL at baseline to 0.5 ng/mL at Month 12. When PROPECIA is used for treatment of male pattern hair loss in older men who also have benign prostatic hyperplasia (BPH), consideration should be given to the fact that, in older men with BPH, PSA levels are decreased by approximately 50%.
PROPECIA is contraindicated for use in women when they are or may potentially be pregnant.
Because of the ability of Type II 5α-reductase inhibitors to inhibit conversion of testosterone to DHT in some tissues, these medicines, including finasteride, may cause abnormalities of the external genitalia of a male foetuses when administered to a pregnant woman.
Women should not handle crushed or broken tablets of PROPECIA when they are or may potentially be pregnant because of the possibility of absorption of finasteride and the subsequent potential risk to a male foetuses. PROPECIA tablets are coated and will prevent contact with the active ingredient during normal handling, provided that the tablets have not been broken or crushed.
PROPECIA is not indicated for use in women.
It is not known whether finasteride is excreted in human milk.
PROPECIA is not indicated for use in children.
Clinical studies with PROPECIA have not been conducted in elderly men with male pattern hair loss.
No evidence of a tumorigenic effect was observed in a 24-month study in rats receiving doses of finasteride up to 320 mg/kg/day (16,000 times the recommended human dose of 1 mg/day).
In a 19-month carcinogenicity study in mice, a statistically significant (p≤ 0.05) increase in the incidence of testicular Leydig cell adenoma was observed at a dose of 250 mg/kg/day (12,500 times the recommended human dose of 1 mg/day); no adenomas were seen in mice given 2.5 or 25 mg/kg/day (125 and 1,250 times the recommended human dose of 1 mg/day, respectively).
In mice at a dose of 25 mg/kg/day and in rats at a dose of ≥40 mg/kg/day (1,250 and ≥2,000 times the recommended human dose of 1 mg/day, respectively), an increase in the incidence of Leydig cell hyperplasia was observed.
A positive correlation between the proliferative changes of the Leydig cells and the increase in serum LH levels (2-3 fold above control) has been demonstrated in both rodent species treated with high doses of finasteride. This suggests the Leydig cell changes are secondary to elevated serum LH levels and not due to a direct effect of finasteride.
No medicine-related Leydig cell changes were seen in either rats or dogs treated with finasteride for one year at doses of 20 mg/kg/day and 45 mg/kg/day (1,000 and 2,250 times the recommended human dose of 1 mg/day, respectively) or in mice treated for 19 months at a dose of 2.5 mg/kg/day (125 times the recommended human dose of 1 mg/day).
No evidence of mutagenicity was observed in an in vitro bacterial mutagenesis assay, a mammalian cell mutagenesis assay, or in an in vitro alkaline elution assay. In an in vitro chromosome aberration assay, when Chinese hamster ovary cells were treated with high concentrations (450-550 (mol) of finasteride, there was a slight increase in chromosome aberrations. These concentrations correspond to 18,000-22,000 times the peak plasma levels in man given a total dose of 1 mg. Further, the concentrations (450-550 (mol) used in the in vitro studies are not achievable in a biological system. In an in vivo chromosome aberration assay in mice, no treatment-related increases in chromosome aberration were observed with finasteride at the maximum tolerated dose (250 mg/kg/day; 12,500 times the recommended human dose of 1 mg/day).
In sexually mature male rabbits treated with finasteride at 80 mg/kg/day (4,000 times the recommended human dose of 1 mg/day) for up to 12 weeks, no effect on fertility, sperm count, or ejaculate volume was seen.
In sexually mature rats treated with the same dose of finasteride, there were no significant effects on fertility after 6 or 12 weeks of treatment; however, when treatment was continued for up to 24 or 30 weeks, there was an apparent decrease in fertility and fecundity, and an associated significant decrease in the weights of the seminal vesicles and prostate. All these effects were reversible within 6 weeks of discontinuation of treatment.
The decrease in fertility in finasteride-treated rats is secondary to its effect on accessory sex organs (prostate and seminal vesicles) resulting in failure to form a seminal plug. The seminal plug is essential for normal fertility in rats and is not relevant in man who do not form copulatory plugs. No medicine-related effect on testes or on mating performance has been seen in rats or rabbits.
Dose-dependant development of hypospadias was observed in the male offspring of pregnant rats given finasteride at doses ranging from 100 mg/kg/day to 100 mg/kg/day (5 to 5,000 times the recommended human dose of 1 mg/day) at an incidence of 3.6 to 100%. Additionally, pregnant rats produced male offspring with decreased prostatic and seminal vesicular weights, delayed preputial separation, and transient nipple development when given finasteride at doses ≥30 mcg/kg/day (≥1.5 times the recommended human dose of 1 mg/day), and decreased anogenital distance when given finasteride in doses 3 mcg/kg/day (approximately one-fifth the recommended human dose of 1 mg/day). The critical period during which these effects can be induced has been defined in male rats as Days 16-17 of gestation.
The changes described above are expected pharmacological effects of Type II 5α-reductase inhibitors. Many of the changes, such as hypospadias, observed in male rats exposed in utero to finasteride are similar to those reported in male infants with a genetic deficiency of Type II 5α-reductase. No effects were seen in female offspring exposed in utero to any dose of finasteride.
Administration of finasteride to rats during the late gestation and lactation period resulted in slightly decreased fertility in first generation male offspring (3 mg/kg/day; 150 times the recommended human dose of 1 mg/day). No developmental abnormalities have been observed in first generation male or female offspring resulting from mating finasteride-treated male rats (80 mg/kg/day; 4,000 times the recommended human dose of 1 mg/day) with untreated females.
No evidence of malformations has been observed in rabbit foetuses exposed to finasteride in utero from Days 6-18 of gestation at doses up to 100 mg/kg/day (5,000 times the recommended human dose of 1 mg/day).
The in utero effects of finasteride exposure during the period of embryonic and foetal development were evaluated in the rhesus monkey (Gestation Days 20-100), a species more predictive of human development than rats or rabbits. Intravenous administration of finasteride to pregnant monkeys at doses as high as 800 ng/day (at least 750 times the highest estimated exposure of pregnant women to finasteride from semen of men taking 1 mg/day) resulted in no abnormalities in male foetuses. In confirmation of the relevance of the rhesus model for human foetal development, oral administration of a very high dose of finasteride (2 mg/kg/day; 100 times the recommended human dose of 1 mg/day or approximately 12 million times the highest estimated exposure to finasteride from semen of men taking 1 mg/day) to pregnant monkeys resulted in external genital abnormalities in male foetuses. No other abnormalities were observed in male foetuses and no finasteride-related abnormalities were observed in female foetuses at any dose.
There are no data to suggest that PROPECIA affects the ability to drive or use machinery.
PROPECIA is generally well tolerated. Adverse effects, which usually have been mild, generally have not required discontinuation of therapy.
Finasteride for male pattern hair loss has been evaluated for safety in clinical studies involving more than 3,200 men. In three 12-month, placebo-controlled, double-blind, multicenter studies of comparable design, the overall safety profiles of PROPECIA and placebo were similar. Discontinuation of therapy due to any clinical adverse experience occurred in 1.7% of 945 men treated with PROPECIA and 2.1% of 934 men treated with placebo.
In these studies, the following medicine-related adverse experiences were reported in ≥1% of men treated with PROPECIA: decreased libido (PROPECIA, 1.8% vs. placebo, 1.3%) and erectile dysfunction (1.3%, 0.7%). In addition, decreased volume of ejaculate was reported in 0.8% of men treated with PROPECIA and 0.4% of men treated with placebo. Resolution of these adverse effects occurred in men who discontinued therapy with PROPECIA and in many who continued therapy. In a separate study, the effect of PROPECIA on ejaculate volume was measured and was not different from that seen with placebo.
The incidence of each of the above adverse effects decreased to ≤ 0.3% by the fifth year of treatment with PROPECIA.
The following adverse experiences have been reported in postmarketing use: ejaculation disorder; breast tenderness and enlargement; hypersensitivity reactions including rash, pruritus, urticaria, and swelling of the lips and face; testicular pain.
No medicine interactions of clinical importance have been identified. Finasteride does not appear to affect the cytochrome P450-linked medicine metabolising enzyme system. Compounds that have been tested in man have included antipyrine, digoxin, glyburide, propranolol, theophylline, and warfarin and no interactions were found.
Although specific interaction studies were not performed, in clinical studies finasteride doses of 1 mg or more were used concomitantly with ACE inhibitors, acetaminophen, alpha blockers, benzodiazepines, beta blockers, calcium-channel blockers, cardiac nitrates, diuretics, H2 antagonists, HMG-CoA reductase inhibitors, prostaglandin synthetase inhibitors (NSAIDs), and quinolones, without evidence of clinically significant adverse interactions.
In clinical studies, single doses of finasteride up to 400 mg and multiple doses of finasteride up to 80 mg/day for three months did not result in adverse effects.
No specific treatment for overdosage with PROPECIA is recommended.
Finasteride is a competitive and specific inhibitor of Type II 5α-reductase with which it slowly forms a stable enzyme complex. Turnover from this complex is extremely slow (t½ ~30 days). Finasteride has no affinity for the androgen receptor and has no androgenic, antiandrogenic, estrogenic, antiestrogenic, or progestational effects. Inhibition of this enzyme blocks the peripheral conversion of testosterone to the androgen dihydrotestosterone (DHT), resulting in significant decreases in serum and tissue DHT concentrations. Finasteride produces a rapid reduction in serum DHT concentration, reaching significant suppression within 24 hours of dosing.
Hair follicles contain Type II 5α-reductase. In men with male pattern hair loss, the balding scalp contains miniaturised hair follicles and increased amounts of DHT. Administration of finasteride decreases scalp and serum DHT concentrations in these men. In addition, men with a genetic deficiency of Type II 5α-reductase do not suffer from male pattern hair loss. These data and the results of the clinical studies confirm that finasteride inhibits the process responsible for miniaturisation of the scalp hair follicles, leading to reversal of the balding process.
Relative to an intravenous reference dose, the oral bioavailability of finasteride is approximately 80%. The bioavailability is not affected by food. Maximum finasteride plasma concentrations are reached approximately two hours after dosing and the absorption is complete after 6-8 hours.
Protein binding is approximately 93%. The volume of distribution of finasteride is approximately 76 litres.
There is modest accumulation of finasteride in plasma after multiple dosing. At steady state following dosing with 1 mg/day, maximum finasteride plasma concentration averaged 9.2 ng/mL and was reached 1 to 2 hours postdose; AUC (0-24 hr) was 53 ng•hr/mL.
Finasteride has been recovered in the cerebrospinal fluid (CSF) but the medicine does not appear to concentrate preferentially to the CSF. A very small amount of finasteride has also been detected in the seminal fluid of subjects receiving finasteride.
Finasteride is metabolised primarily via the cytochrome P450 3A4 enzyme subfamily. Following an oral dose of 14C-finasteride in man, two metabolites of finasteride were identified that possess only a small fraction of the 5α-reductase inhibitory activity of finasteride.
Following an oral dose of 14C-finasteride in man, 39% of the dose was excreted in the urine in the form of metabolites (virtually no unchanged medicine was excreted in the urine) and 57% of total dose was excreted in the faeces.
Plasma clearance is approximately 165 mL/min.
The elimination rate of finasteride decreases somewhat with age. Mean terminal half-life is approximately 5-6 hours in men 18-60 years of age and 8 hours in men more than 70 years of age. These findings are of no clinical significance and hence, a reduction in dosage in the elderly is not warranted.
No adjustment in dosage is necessary in nondialysed patients with renal impairment.
Store below 30°C . Keep container closed and protect from moisture.
Prescription Medicine.
PROPECIA is available in packs of 28 tablets.
Finasteride is described chemically as: N-(1,1-dimethylethyl)-3-oxo-4-aza-5α-androst-1-ene-17β-carboxamide.
Its empirical formula is C23H36N2O2 and its structural formula is:
Finasteride is a white, crystalline solid with a molecular weight of 372.55. It is freely soluble in chloroform and in lower alcohol solvents but is practically insoluble in water.
Each film-coated tablet of PROPECIA contains 1 mg of finasteride.
Each film-coated tablet contains the following inactive ingredients: lactose monohydrate, microcrystalline cellulose, pregelatinised starch, sodium starch glycolate, docusate sodium, magnesium stearate, hydroxypropyl methylcellulose 2910, hydroxypropyl cellulose, titanium dioxide, talc, yellow ferric oxide, and red ferric oxide.
Merck Sharp & Dohme (New Zealand) Limited
P O Box 99 851
Newmarket
Auckland
Tel: 0800 500 673
14 February 2005
DP-PPC-0205(140205)
® Registered Trademark of Merck & Co., Inc., Whitehouse Station, NJ USA