PROPECIA®(finasteride)Tablets, 1 mg
DESCRIPTION
PROPECIA* (finasteride), a synthetic 4-azasteroid compound, is a specific inhibitor of steroid Type II
5?-reductase, an intracellular enzyme that converts the androgen testosterone into
5?-dihydrotestosterone (DHT).
Finasteride is 4-azaandrost-1-ene-17-carboxamide,N-(1,1-dimethylethyl)-3-oxo-,(5?,17?)-. The
empirical formula of finasteride is C23H36N2O2 and its molecular weight is 372.55.
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INDICATIONS AND USAGE
PROPECIA is indicated for the treatment of male pattern hair loss (androgenetic alopecia) in MEN
ONLY. Safety and efficacy were demonstrated in men between 18 to 41 years of age with mild to
moderate hair loss of the vertex and anterior mid-scalp area (see CLINICAL PHARMACOLOGY, Clinical
Studies).
Efficacy in bitemporal recession has not been established.
PROPECIA is not indicated in women (see CLINICAL PHARMACOLOGY, Clinical Studies and
CONTRAINDICATIONS).
PROPECIA is not indicated in children (see PRECAUTIONS, Pediatric Use).
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OVERDOSAGE
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 reactions. Until further experience is obtained, no
specific treatment for an overdose with finasteride can be recommended.
Significant lethality was observed in male and female mice at single oral doses of 1500 mg/m2
(500 mg/kg) and in female and male rats at single oral doses of 2360 mg/m2 (400 mg/kg) and
5900 mg/m2 (1000 mg/kg), respectively.
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DOSAGE AND ADMINISTRATION
The recommended dosage is 1 mg orally once a day.
PROPECIA may be administered with or without meals.
In general, daily use for three months or more is necessary before benefit is observed. Continued use
is recommended to sustain benefit, which should be re-evaluated periodically. Withdrawal of treatment
leads to reversal of effect within 12 months.
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CLINICAL PHARMACOLOGY
Finasteride is a competitive and specific inhibitor of Type II 5?-reductase, an intracellular enzyme that
converts the androgen testosterone into DHT. Two distinct isozymes are found in mice, rats, monkeys,
and humans: Type I and II. Each of these isozymes is differentially expressed in tissues and
developmental stages. In humans, Type I 5?-reductase is predominant in the sebaceous glands of most
regions of skin, including scalp, and liver. Type I 5?-reductase is responsible for approximately one-third
of circulating DHT. The Type II 5?-reductase isozyme is primarily found in prostate, seminal vesicles,
epididymides, and hair follicles as well as liver, and is responsible for two-thirds of circulating DHT.
In humans, the mechanism of action of finasteride is based on its preferential inhibition of the Type II
isozyme. Using native tissues (scalp and prostate), in vitro binding studies examining the potential of
finasteride to inhibit either isozyme revealed a 100-fold selectivity for the human Type II 5?-reductase
over Type I isozyme (IC50=500 and 4.2 nM for Type I and II, respectively). For both isozymes, the
inhibition by finasteride is accompanied by reduction of the inhibitor to dihydrofinasteride and adduct
formation with NADP+. The turnover for the enzyme complex is slow (t1/2 approximately 30 days for the
Type II enzyme complex and 14 days for the Type I complex).
Finasteride has no affinity for the androgen receptor and has no androgenic, antiandrogenic,
estrogenic, antiestrogenic, or progestational effects. Inhibition of Type II 5?-reductase blocks the
peripheral conversion of testosterone to DHT, resulting in significant decreases in serum and tissue DHT
concentrations.
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CONTRAINDICATIONS
PROPECIA is contraindicated in the following:
Pregnancy. Finasteride use is contraindicated in women when they are or may potentially be
pregnant. Because of the ability of Type II 5?-reductase inhibitors to inhibit the conversion of testosterone
to DHT, finasteride may cause abnormalities of the external genitalia of a male fetus of a pregnant
woman who receives finasteride. 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. (See
also WARNINGS, EXPOSURE OF WOMEN - RISK TO MALE FETUS; and PRECAUTIONS, Information
for Patients and Pregnancy.) In female rats, low doses of finasteride administered during pregnancy have
produced abnormalities of the external genitalia in male offspring.
Hypersensitivity to any component of this medication.
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WARNINGS
PROPECIA is not indicated for use in pediatric patients (see INDICATIONS AND USAGE; and
PRECAUTIONS, Pediatric Use) or women (see also WARNINGS, EXPOSURE OF WOMEN - RISK TO
MALE FETUS; PRECAUTIONS, Information for Patients and Pregnancy; and HOW SUPPLIED, Storage
and Handling).
EXPOSURE OF WOMEN - RISK TO MALE FETUS
Women should not handle crushed or broken PROPECIA tablets when they are pregnant or may
potentially be pregnant because of the possibility of absorption of finasteride and the subsequent
potential risk to a male fetus. PROPECIA tablets are coated and will prevent contact with the active
PROPECIA® (Finasteride) Tablets, 1 mg 9636001
ingredient during normal handling, provided that the tablets have not been broken or crushed. (See also
CONTRAINDICATIONS; PRECAUTIONS, Information for Patients and Pregnancy; and HOW
SUPPLIED, Storage and Handling.)
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PRECAUTIONS
General
Caution should be used in the administration of PROPECIA in patients with liver function
abnormalities, as finasteride is metabolized extensively in the liver.
Information for Patients
Women should not handle crushed or broken PROPECIA tablets when they are pregnant or may
potentially be pregnant because of the possibility of absorption of finasteride and the subsequent
potential risk to a male fetus. 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. (See also
CONTRAINDICATIONS; WARNINGS, EXPOSURE OF WOMEN - RISK TO MALE FETUS;
PRECAUTIONS, Pregnancy; and HOW SUPPLIED, Storage and Handling.)
Physicians should instruct their patients to promptly report any changes in their breasts such as
lumps, pain or nipple discharge. Breast changes including breast enlargement, tenderness and neoplasm
have been reported (see ADVERSE REACTIONS).
See also Patient Package Insert.
Physicians should instruct their patients to read the patient package insert before starting therapy with
PROPECIA and to read it again each time the prescription is renewed so that they are aware of current
information for patients regarding PROPECIA.
Drug/Laboratory Test Interactions
Finasteride had no effect on circulating levels of cortisol, thyroid-stimulating hormone, or thyroxine, nor
did it affect the plasma lipid profile (e.g., total cholesterol, low-density lipoproteins, high-density
lipoproteins and triglycerides) or bone mineral density. In studies with finasteride, no clinically meaningful
changes in luteinizing hormone (LH), follicle-stimulating hormone (FSH) or prolactin were detected. In
healthy volunteers, treatment with finasteride did not alter the response of LH and FSH to gonadotropinreleasing
hormone indicating that the hypothalamic-pituitary-testicular axis was not affected.
In clinical studies with PROPECIA (finasteride, 1 mg) 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.
Further, in clinical studies with PROSCAR (finasteride, 5 mg) when used in older men who have benign
prostatic hyperplasia (BPH), PSA levels are decreased by approximately 50%. These findings should be
taken into account for proper interpretation of serum PSA when evaluating men treated with finasteride.
Drug Interactions
No drug interactions of clinical importance have been identified. Finasteride does not appear to affect
the cytochrome P450-linked drug-metabolizing enzyme system. Compounds that have been tested in
man include antipyrine, digoxin, propranolol, theophylline, and warfarin and no clinically meaningful
interactions were found.
Other concomitant therapy: Although specific interaction studies were not performed, finasteride
doses of 1 mg or more were concomitantly used in clinical studies with acetaminophen, acetylsalicylic
acid, ?-blockers, analgesics, angiotensin-converting enzyme (ACE) inhibitors, anticonvulsants,
benzodiazepines, beta blockers, calcium-channel blockers, cardiac nitrates, diuretics, H2 antagonists,
HMG-CoA reductase inhibitors, prostaglandin synthetase inhibitors (also referred to as NSAIDs), and
quinolone anti-infectives without evidence of clinically significant adverse interactions.
Carcinogenesis, Mutagenesis, Impairment of Fertility
No evidence of a tumorigenic effect was observed in a 24-month study in Sprague-Dawley rats
receiving doses of finasteride up to 160 mg/kg/day in males and 320 mg/kg/day in females. These doses
produced respective systemic exposure in rats of 888 and 2192 times those observed in man receiving
the recommended human dose of 1 mg/day. All exposure calculations were based on calculated
AUC(0-24 hr) for animals and mean AUC(0-24 hr) for man (0.05 ?g•hr/mL).
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