Finasteride is a synthetic 4-azasteroid compound. Finasteride competitively binds to and inhibits steroid type II 5-alpha-reductase in the prostate gland, liver, and skin, thereby interfering with the enzymatic conversion of testosterone to 5-dihydrotestosterone (DHT) and reducing serum DHT levels. The reduction in serum DHT levels results in diminished stimulation of androgen receptors in the nuclei of prostate cells and, so, diminished prostate cell proliferation.
Finasteride, sold under the brand names Proscar and Propecia among others, is a medication used mainly to treat an enlarged prostate or scalp hair loss in men.[rx][rx][rx] It can also be used to treat excessive hair growth in women and as a part of hormone therapy for transgender women.[rx][rx] It is taken by mouth.[rx]
Mechanism of Action of Finasteride
Indications of Finasteride
- Treatment of benign prostatic hypertrophy
- For the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate to Improve symptoms, reduce the risk of acute urinary retention, reduce the risk of the need for surgery including transurethral resection of the prostate. Also used for the stimulation of regrowth of hair in men with mild to moderate androgenetic alopecia (male pattern alopecia, hereditary alopecia, common male baldness).
- Finasteride is a 5-alpha-reductase inhibitor used to treat symptoms of benign prostatic hypertrophy and male pattern baldness. Finasteride is associated with a low rate of transient serum aminotransferase elevations but has yet to be linked to instances of clinically apparent, acute liver injury.
- Benign Prostatic Hyperplasia
- Androgenetic Alopecia
Contraindications of Finasteride
- Finasteride may cause birth defects in a male fetus if a pregnant woman takes finasteride or is exposed to finasteride pill fragments.[rx][rx] [rx] Finasteride induces ambiguous genitalia in male fetuses when given to pregnant rhesus monkeys, whereas no abnormalities are observed in female fetuses. There is a single case report of accidental finasteride exposure during pregnancy, although in a female infant.[rx][rx]
- Malignant tumor of male breast
- Liver problems
- Pregnancy
- A mother who is producing milk and breastfeeding
- High-Grade Prostate Cancer
Allergies to
- 5-Alfa Reductase Inhibitor
- Azasteroids
- Finasteride
Dosage of Finasteride
Strengths: 1 mg; 5 mg
Benign Prostatic Hyperplasia
- 5 mg orally once a day
Androgenetic Alopecia
- 1 mg orally once a day
For the treatment of male pattern hair loss (androgenetic alopecia) in men only. (Safety and efficacy have been demonstrated in men between 18 to 41 years of age with mild to moderate hair loss of the vertex and anterior mid-scalp area)
Side Effects of Finasteride
The Most Common
- breast enlargement, tenderness, lumps, or nipple discharge
- continued ejaculation problems after stopping the medication
- decreased interest in sexual activity continuing after stopping the medication
- decreased sexual ability continuing after stopping the medication
- infertility or poor quality of semen
- muscle pain or weakness
- signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
- signs of an allergic reaction including (e.g., skin rash, itchiness, hives, swelling of the lips or tongue)
Common
- Chest pain or discomfort
- dilated neck veins
- extreme fatigue
- irregular breathing
- irregular heartbeat
- shortness of breath
- swelling of the face, fingers, feet, or lower legs
- weight gain
- wheezing
Rare
- Blistering, flaking, or peeling of the skin
- cough
- difficulty with swallowing
- dizziness
- fast heartbeat
- hives or welts
- itching skin
- large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
- puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
- redness of the skin
- skin rash
- tightness in the chest
- unusual tiredness or weakness
- wheezing
Drug Interactions of Finasteride
may interact with following drugs, supplements & may change the efficacy of the drug
- “azole” antifungals (e.g., fluconazole, itraconazole, ketoconazole)
- allopregnanolone from progesterone and hence may reduce or block the sedative, anticonvulsant, anxiolytic, and various other effects of progesterone,
- boceprevir
- chloramphenicol
- cimetidine
- ciprofloxacin
- clarithromycin
- conivaptan
- cyclosporine
- delavirdine
- diltiazem
- grapefruit juice
- macrolide antibiotics (e.g., clarithromycin, erythromycin)
- nelfinavir
- nicardipine
- propranolol
- protease inhibitors (e.g., indinavir, ritonavir, saquinavir)
- St. John’s Wort
- verapamil
Pregnancy Category
FDA Pregnancy Category – X
Pregnancy
When absorbed into the system of a pregnant woman, finasteride may cause abnormalities of the genitals in a male baby. Crushed or broken finasteride tablets should not be handled by women who are or may become pregnant because finasteride may be absorbed into their system through the skin.
Lactation
Finasteride should not be used by children.
References
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