Trade Names:Propecia- Tablets 1 mg
Trade Names:Proscar- Tablets 5 mg
Inhibits conversion of testosterone into 5-alpha-dihydrotestosterone, a potent androgen.
Mean bioavailability is 65% (range, 26% to 170%). C max at steady state is 4.9 to 13.7 ng/mL (mean, 9.2 ng/mL) ( Propecia ). C max is 37 ng/mL (range, 27 to 49 ng/mL) ( Proscar ). T max is 1 to 2 h. AUC 0-24 is 20 to 154 ng•h/mL (mean, 53 ng•h/mL).
Vd ss is 44 to 96 L (mean, 76 L) and is about 90% bound to plasma proteins. The drug crosses the blood-brain barrier but does not appear to distribute preferentially to the CSF.
Extensively metabolized in the liver, primarily via the CYP-450 3A4 enzyme subfamily. Two metabolites have been identified: t-butyl side chain monohydroxylated and monocarboxylic acid; each possesses no more than 20% activity.
Plasma Cl is 70 to 279 mL/min (mean, 165 mL/min). Mean t ½ is 4.8 h (range, 3.3 to 13.4 h) ( Propecia ). Mean t ½ is 6 h (range, 3 to 16 h) ( Proscar ); 32% to 46% is excreted in the urine as metabolites, and 51% to 64% is excreted in the feces.
Mean t ½ increases to 8 h (70 yr of age and older). Mean AUC 0-24 increases 15%.
Treatment of male pattern hair loss (androgenic alopecia) in men only.Proscar
Treatment of symptomatic benign prostatic hyperplasia (BPH) in men with enlarged prostate; in combination with doxazosin to reduce the risk of symptomatic progression of BPH.
Use during pregnancy; use in women or children.
PO Propecia : 1 mg daily. Proscar : 5 mg daily.
None well documented.
Decreased prostate-specific antigen levels.
Postural hypotension (9%); hypotension (1%).
Decreased libido (2%).Proscar
Decreased libido (10%); dizziness (7%); headache, somnolence (2%).
Erectile dysfunction, ejaculation disorders (1%); breast tenderness/enlargement in men (postmarketing).Proscar
Impotence (19%); abnormal ejaculation (7%); decreased volume of ejaculate (4%); abnormal sexual function (3%); breast enlargement in men (2%).
Pruritus, urticaria, swelling of lips and face, testicular pain (postmarketing).
Peripheral edema (1%).
Category X .
Safety and efficacy not established.
Use with caution.
Based on animal studies, may have carcinogenic or mutagenic potential.
Minimum 6 mo therapy may be necessary to see effect ( Proscar ). Minimum 3 mo therapy may be necessary to see effect ( Propecia ).
Carefully monitor patients with large residual urine volume or severely diminished urinary flow.
Carefully evaluate any increase in PSA level, consider noncompliance with therapy.
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