section name header

Information ⬇

finasteride

fin-as-ter-ide

Trade Name(s): (Propecia, Proscar)

Do not confuse finasteride with furosemide, or Proscar with ProSom, Provera, or PROzac.

FIXED-COMBINATION(S)

Entadfi: finasteride/tadalafil (PDE5 inhibitor): 5 mg/5 mg.

Classification ⬆ ⬇

Uses ⬆ ⬇

Proscar: Treatment (monotherapy) of symptomatic benign prostatic hyperplasia (BPH) to improve symptoms, reduce risk of acute urinary retention, or reduce the need for surgery, including transurethral resection of the prostate (TURP) and prostatectomy. Used in combination with an alpha-blocker (e.g., doxazosin) to reduce risk of symptomatic progression. Propecia: Treatment of male pattern hair loss. OFF-LABEL: Treatment of female hirsutism.

Precautions ⬆ ⬇

Contraindications: Hypersensitivity to finasteride, pregnancy or women of child-bearing potential. Cautions: Hepatic impairment, urinary outflow obstruction, urinary retention. Women who are attempting to conceive should avoid exposure to crushed or broken tablets.

Action ⬆ ⬇

Inhibits 5-alpha reductase, an intracellular enzyme that converts testosterone into dihydrotestosterone (DHT) in prostate gland, resulting in decreased serum DHT. Therapeutic Effect: Reduces size of prostate gland.

Pharmacokinetics ⬆ ⬇

RouteOnsetPeakDuration
PO (reduction of DHT)8 hrs24 hrs

Widely distributed. Protein binding: 90%. Metabolized in liver. Half-life: 6–8 hrs. Onset of clinical effect: 3–6 mos of continued therapy.

Lifespan Considerations ⬆ ⬇

Pregnancy/Lactation: Physical handling of tablet by those who are or may become pregnant may produce abnormalities of external genitalia of male fetus. Children: Not indicated for use in children. Elderly: No age-related precautions noted.

Interactions ⬆ ⬇

DRUG: None significant. HERBAL: None significant. FOOD: None known. LAB VALUES: Decreases serum prostate-specific antigen (PSA) level, even in presence of prostate cancer. Decreases dihydrotestosterone (DHT). Increases follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone.

Availability ⬆ ⬇

Tablets:1 mg (Propecia), 5 mg (Proscar).

Administration/Handling ⬆ ⬇

PO
  • Do not break, crush, dissolve, or divide film-coated tablets.
  • Give without regard to food.

Indications/Routes/Dosage ⬆ ⬇

Benign Prostatic Hyperplasia (BPH)

PO: ADULTS, ELDERLY:(Proscar): 5 mg once daily. Use as single agent or in combination with an alpha-1 adrenergic antagonist (e.g., doxazosin) (6–12 mos of treatment usually needed to assess benefit).

Hair Loss

PO: ADULTS:(Propecia): 1 mg/day (continue for at least 12 mos to assess full benefit).

Dosage in Renal Impairment

No dose adjustment.

Dosage in Hepatic Impairment

Use caution.

Side Effects ⬆ ⬇

Rare (4%–2%): Gynecomastia, sexual dysfunction (impotence, decreased libido, decreased volume of ejaculate).

Adverse Effects/Toxic Reactions ⬆ ⬇

Hypersensitivity reaction, circumoral swelling, testicular pain occur rarely.

Nursing Considerations ⬆

  • BASELINE ASSESSMENT Digital rectal exam, serum prostate-specific antigen (PSA) determination should be performed in pts with benign prostatic hyperplasia (BPH) before initiating therapy and periodically thereafter. Assess usual urinary characteristics (frequency, ability to empty bladder, urinary flow). Assess degree of urinary retention with bladder scan. INTERVENTION/EVALUATION Diligently monitor urinary output, esp. in pts with large residual urinary volume, severely diminished urinary flow, or obstructive uropathy. Obtain periodic bladder scan to assess treatment effectiveness (or to assess for acute urinary retention). PATIENT/FAMILY TEACHING
  • Treatment may cause impotence, decreased volume of ejaculate.
  • May not notice improved urinary flow even if prostate gland shrinks.
  • Must take medication longer than 6 mos, and it is unknown if medication decreases need for surgery.
  • Because of potential risk to fetus, women who are or may become pregnant should not handle tablets or be exposed to pt's semen.
  • Immediately report inability to urinate or severe bladder pain.