Therapeutic: hair regrowth stimulants
Pharmacologic: androgen inhibitors
Benign prostatic hyperplasia (BPH); can be used with doxazosin. Androgenetic alopecia (male pattern baldness) in men only.
Inhibits the enzyme 5-alpha-reductase, which is responsible for converting testosterone to its potent metabolite 5-alpha-dihydrotestosterone in prostate, liver, and skin; 5-alpha-dihydrotestosterone is partially responsible for prostatic hyperplasia and hair loss. Therapeutic Effects: Reduced prostate size with associated decrease in urinary symptoms. Decreases hair loss; promotes hair regrowth.
Adverse Reactions/Side Effects
GU: decreased libido, decreased volume of ejaculate, erectile dysfunction.
PHYSICAL THERAPY IMPLICATIONS
Examination and Evaluation
When treating BPH, monitor signs such as difficulty starting a urine stream, painful urination, weak urine flow, feeling that the bladder is not completely empty, frequent nighttime urination, and an urge to urinate again soon after urinating. Document any change in BPH symptoms to help assess the effects of drug therapy.
When treating BPH, advise patient that urinary symptoms (retention, dribbling, hesitancy, urgency) should improve, and to contact the physician if these symptoms continue to worsen.
Instruct patient to report other bothersome side effects such as decreased libido or erectile dysfunction.
Absorption: Well absorbed after oral administration (63%).
Distribution: Enters prostatic tissue and crosses the blood-brain barrier. Remainder of distribution not known.
Metabolism and Excretion: Mostly metabolized; 39% excreted in urine as metabolites; 57% excreted in feces.
Half-life: 6 hr (range 6–15 hr; slightly increased in patients >70 yr).
TIME/ACTION PROFILE (reduction in dihydrotestosterone levels*)
|ROUTE ||ONSET ||PEAK ||DURATION |
|PO ||rapid ||8 hr ||2 wk |
Contraindicated in: Hypersensitivity; Women.
Use Cautiously in: Patients with hepatic impairment or obstructive uropathy.
PO (Adults): BPH—5 mg once daily (Proscar); androgenetic alopecia—1 mg/day (Propecia).
Availability (generic available)
Tablets: 1 mg (Propecia), 5 mg (Proscar).