Proscar

Proscar contains finasteride 5 mg, a 5-alpha reductase inhibitor prescribed for the treatment of benign prostatic hyperplasia (BPH).

It reduces the size of the enlarged prostate gland, improves urinary flow, and lowers the risk of acute urinary retention and the need for surgical intervention.

Finasteride inhibits the type II 5-alpha reductase enzyme, which converts testosterone to dihydrotestosterone (DHT) in the prostate. DHT is the principal androgen responsible for prostate growth.

By reducing intraprostatic DHT levels by approximately 70-80%, finasteride causes gradual shrinkage of the gland over several months.

Clinical Evidence

Large-scale trials have shown that finasteride 5 mg reduces prostate volume by about 20-30% over six to twelve months, improves symptom scores, increases urinary flow rate, and reduces the relative risk of acute urinary retention by approximately 57% and the need for BPH-related surgery by about 55%.

Distinction from Propecia

Proscar (finasteride 5 mg) is specifically for BPH. Propecia (finasteride 1 mg) is licensed for male-pattern hair loss. The two doses should not be interchanged without medical advice.

How to Take Proscar

Swallow one tablet daily with water, with or without food. Take it at the same time each day.

Duration

Proscar requires at least six months of continuous use before the full benefit on urinary symptoms becomes apparent.

Some improvement may be felt within the first few months, but early discontinuation prevents the full therapeutic effect.

PSA Monitoring

Finasteride approximately halves the serum PSA level. When interpreting PSA results for prostate cancer screening, your doctor must double the measured value to estimate the true PSA level.

Inform any new doctor or laboratory that you take finasteride.

Women and Children

Women of childbearing potential and children must not handle crushed or broken Proscar tablets, as finasteride can be absorbed through the skin and may cause birth defects in a male foetus.

Adults (Men Only)

• 5 mg once daily

Duration

• Minimum 6 months before assessing benefit
• Long-term (years) treatment is typically needed, as BPH recurs on stopping

Renal Impairment

• No dose adjustment required (minimal renal excretion)

Hepatic Impairment

• No formal studies; use with caution in significant liver disease

Not For Use In

• Women or children
• Men using finasteride 1 mg (Propecia) concurrently

Common (up to 1 in 10 patients, especially in the first year)

• Decreased libido
• Erectile dysfunction
• Reduced ejaculate volume

Uncommon (up to 1 in 100 patients)

• Breast tenderness or gynaecomastia (breast enlargement)
• Rash
• Ejaculation disorder

Rare (up to 1 in 1,000 patients)

• Depression
• Allergic reactions (pruritus, urticaria, angioedema)

Very Rare / Post-marketing

• Persistent sexual dysfunction after stopping the drug (reported anecdotally; causality debated)
• Male breast cancer (very rare; causal link unconfirmed)
• Testicular pain

Sexual side effects are the most commonly reported reason for discontinuation. They resolve in most men after stopping treatment, though a small number report persistent effects.

Sexual Side Effects

Decreased libido and erectile dysfunction occur in a small proportion of men and usually reverse on stopping treatment.

However, there are post-marketing reports of persistent sexual dysfunction after discontinuation. Discuss this with your prescriber before starting.

PSA and Prostate Cancer Screening

Finasteride reduces PSA by approximately 50%. Any sustained rise in PSA during treatment, even if within the normal range, should be investigated, as it may indicate prostate cancer.

Exposure in Women

Pregnant women or women who may become pregnant must not handle crushed or broken tablets. Finasteride can cause abnormalities of the external genitalia in a male foetus.

Intact tablets have a coating that prevents contact during normal handling.

Mood Changes

Monitor for depression or low mood, especially in the first year of treatment. Report changes to your prescriber.

Do not take Proscar if you have:

• A known hypersensitivity to finasteride or any excipient
• You are a woman (Proscar is not indicated for women)
• You are a child or adolescent

Women of childbearing potential must not handle crushed or broken tablets due to the risk of foetal harm.

Proscar should not be used together with finasteride 1 mg (Propecia).