Proscar
enUKfinasteride
Pharmacologic class: Androgen inhibitor
Therapeutic class: Sex hormone, hair regrowth stimulant
Pregnancy risk category X
Action
Suppresses dihydrotestosterone levels by inhibiting the hepatic enzyme 5-alpha reductase, which converts testosterone to dihydrotestosterone in prostate, liver, and skin
Availability
Tablets: 1 mg (Propecia), 5 mg (Proscar)
Indications and dosages
➣ Symptomatic benign prostatic hypertrophy (BPH)
Adults: 5 mg P.O. daily
➣ To reduce risk of progression of BPH symptoms
Adults: 5 mg P.O. daily (Proscar) given with doxazosin
➣ Male-pattern baldness
Adults: 1 mg P.O. daily
Off-label uses
• Acne in women
• Hirsutism
Contraindications
• Hypersensitivity to drug or its components
• Pregnant patients, women who may potentially be pregnant
Precautions
Use cautiously in:
• hepatic impairment, obstructive uropathy, increased risk of high-grade prostate cancer, decrease in serum prostate-specific antigen (PSA) level
• women (not indicated)
• children (not indicated).
Administration
• Give with or without food.
• Know that female patients who are or may be pregnant shouldn't handle crushed or broken tablets. (Tablets are coated, so handling of intact tablets doesn't pose a problem.)
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Adverse reactions
CNS: dizziness, headache, asthenia
EENT: lip swelling
GU: erectile dysfunction, decreased ejaculate volume, decreased libido, testicular pain, gynecomastia
Musculoskeletal: back pain
Skin: rash
Interactions
Drug-drug. Theophylline: increased theophylline clearance
Drug-diagnostic tests. PSA: 50% decrease
Patient monitoring
• Carefully evaluate sustained PSA increases during therapy.
• Monitor fluid intake and output closely.
Patient teaching
• Tell patient he may take drug with or without food.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Inform patient that he may experience erectile dysfunction and decreased ejaculate. Advise him to discuss these issues with prescriber.
• Caution female caregiver or companion who is or may be pregnant not to handle crushed or broken tablets.
• Tell patient he may need at least 6 months of therapy for BPH treatment and at least 3 months to see improvement in male-pattern baldness.
• Inform patient with BPH that he'll undergo periodic digital rectal exams.
• Instruct patient not to donate blood for at least 1 month after last dose.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs and tests mentioned above.