Hyplafin (Finasteride)

Finasteride is used in conditions related to androgen‑dependent tissue growth.

• Benign prostatic hyperplasia: reduces prostate volume, lowers serum prostate‑specific antigen, and improves urinary flow and symptom scores in men with enlarged prostate.
• Male pattern hair loss (androgenetic alopecia): decreases hair shedding, increases hair density, and promotes regrowth on the scalp in male patients.
• Prostate enlargement (BPH): alleviates lower urinary tract symptoms such as hesitancy, weak stream, nocturia, and frequency, improving quality of life.
• Prostate cancer chemoprevention: lowers dihydrotestosterone levels, which may reduce the risk of developing low‑grade prostate cancer in certain men.

• Finasteride selectively inhibits the type II isoform of the enzyme 5‑alpha‑reductase. By blocking this enzyme, the conversion of testosterone to the more potent androgen dihydrotestosterone (DHT) is reduced in target tissues such as the prostate and scalp hair follicles. The resulting lower DHT concentrations diminish androgen‑driven cellular proliferation and miniaturization, leading to therapeutic effects in benign prostatic hyperplasia and androgenetic alopecia. The inhibition is dose‑dependent and reversible, allowing normal androgen activity to resume after discontinuation.

Finasteride may cause a range of adverse reactions, which are classified by frequency and severity.

Common Side Effects

• Decreased libido: a reduction in sexual desire that can affect personal relationships and overall wellbeing.
• Erectile dysfunction: difficulty in achieving or maintaining an erection sufficient for satisfactory sexual activity.
• Reduced semen volume: a noticeable decline in the amount of ejaculate produced during orgasm.
• Breast tenderness or enlargement: mild swelling, pain, or increase in breast size, usually reversible after discontinuation.

Serious or Rare Side Effects

• Allergic reactions: skin rash, urticaria, or angioedema that may require immediate medical evaluation.
• Breast cancer: isolated reports of malignant breast tissue development, considered a rare but serious potential risk.

When prescribing finasteride, several precautions should be observed to ensure patient safety.

• Pregnancy contraindication: finasteride is classified as pregnancy category X and must not be used by women who are pregnant or may become pregnant.
• Women of childbearing potential: should avoid handling crushed or broken tablets to prevent absorption.
• Prostate monitoring: regular assessment of prostate-specific antigen (PSA) levels is recommended during therapy.
• Liver function: evaluate hepatic function before initiation and monitor if liver disease is present.
• Drug hypersensitivity: discontinue if signs of allergic reaction such as rash or swelling appear.
• Store at below 25°C: keep tablets in the original packaging, protect from moisture and direct sunlight.

Finasteride can interact with other medicines, and interactions are grouped by clinical significance.

Major Interactions (Avoid)

• Concomitant use with other 5‑alpha‑reductase inhibitors (e.g., dutasteride) may increase the risk of hormonal side effects.
• Combined therapy with testosterone or other androgen supplements can diminish finasteride’s efficacy.

Moderate Interactions (Monitor Closely)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole) may raise plasma concentrations of finasteride.
• Antiretroviral agents such as ritonavir can alter finasteride metabolism and require monitoring.
• Warfarin: finasteride may affect coagulation parameters; INR should be checked regularly.