Finasteride 5 mg is used to treat benign prostatic hyperplasia by lowering dihydrotestosterone levels, which shrinks the prostate and improves urinary flow. It should be taken once daily as prescribed and not stopped without medical advice. Common side effects include dizziness, chills, and confusion, while less common ones include swelling, breast tenderness, and skin reactions. 

The medicine is unsafe in pregnancy, children, and liver disease. It does not interact with food but alcohol may alter its effect. Store at room temperature, away from sunlight and children. Missed doses should be taken when remembered unless near the next dose, and overdose requires immediate medical attention. 

Finasteride 5 mg is an oral medicine belonging to the class of 5-alpha reductase inhibitors medicines. It is used for the treatment of enlarged prostate gland (prostatic hyperplasia).

1. Take finasteride exactly as prescribed by your doctor, regularly at the same time each day. 
2. Do not stop taking finasteride without your doctor’s approval, even if you feel better. 
3. If you forget to take the medicine, take it as soon as you remember, unless it’s almost time for the next one, then just skip it. 

More Common

1. Chills 
2. Cold sweats 
3. Confusion 
4. Dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position 

Less Common

1. Bloating or swelling of the face, arms, hands, lower legs, or feet 
2. Breast enlargement and tenderness 
3. Hives or welts, itching, skin rash 
4. Rapid weight gain 
5. Redness of the skin 
6. Swelling of the lips and face 
7. Tingling of the hands or feet 
8. Unusual weight gain or loss 

Finasteride 5 mg selectively inhibits type II and III 5-alpha reductase enzymes present in prostatic tissue, reducing dihydrotestosterone (DHT) level by up to 90%. This leads to shrinkage of enlarged prostate improvement in urinary flow and reduction of  benign prostatic hyperplasia symptoms. DHT levels return to normal within 14 days after stopping the therapy. 

Pregnancy

Pregnant women should avoid this finasteride as it may cause fetal abnormalities.

Children

Children should avoid this medicine as it may be harmful to their bodies. 

Liver Disease

Avoid this medicine if you have liver disease, as it may cause further liver damage.

Avoid taking Finasteride 5 mg with the following medicines, as it may increase or decrease the desired effect, or in worse cases, it could be fatal: 

Finasteride does not interact with any food products, but alcohol should be avoided before and after taking the medicine, as it can increase or decrease the effect of the medicine. 

1. The medicine should be stored at room temperature  
2. Keep away from sunlight and moisture  
3. Keep away from the reach of children 

IUPAC (International Union of Pure and Applied Chemistry)/ Chemical name

(1S,3aS,3bS,5aR,9aR,9bS,11aS)-N-tert-butyl-9a,11a-dimethyl-7-oxo-1,2,3,3a,3b,4,5,5a,6,9b,10,11-dodecahydroindeno[5,4-f]quinoline-1-carboxamide. 

Daily Dose

Take finasteride exactly as your doctor recommends. The dose may change based on your condition and how well you respond. Do not take more than prescribed without consulting your doctor.

Missed Dose

If you forget to take your medicine, take the medication soon as you remember. If it’s nearly time for your next dose, skip the missed one and continue with your regular schedule. Always consult the doctor before making any changes to your dosage.

Overdose

A dose exceeding 400 mg is considered toxic. Overdose symptoms include high blood pressure, dizziness, and vomiting. If someone taking finasteride experiences these symptoms, inform a doctor immediately.

Can finasteride cause erectile dysfunction? 

Yes, a study by Northwestern Medicine found that men who took finasteride or dutasteride for a longer duration had a higher risk of persistent erectile dysfunction, even after stopping the medication. In some cases, the condition lasted for months or even years. 

Can finasteride cause cancer? 

Finasteride lowers prostate cancer risk, but earlier studies suggested it might increase aggressive cases, leading to an FDA warning. Later research found this was likely due to better detection, and a 2019 study confirmed it doesn’t raise the risk of dying from prostate cancer. 

Will finasteride stop hair loss? 

Finasteride 1 mg daily slows down male pattern hair loss and helps maintain hair density, but it doesn’t stop or reverse hair loss permanently. Most men see benefits, especially in the first year. 

1. Paul M. Hair loss and prostate drugs linked to persistent erectile dysfunction in men [Internet]. Northwestern Now; 2017 Mar 9. Available from. 
2. National Cancer Institute. Prostate cancer prevention: findings clarify impact of finasteride. Cancer Currents Blog [Internet]. 2019 Jan 24 [cited 2025 Mar 12]. Available from. 
3. Midland Skin. Finasteride [Internet]. [cited 2025 Mar 12]. Available from. 
4. Aventus Clinic. Finasteride Shedding: What Is It & How Long Does It Last? [Internet]. [cited 2025 Mar 12]. Available from. 
5. Zito PM, Bistas KG, Patel P, et al. Finasteride. [Updated 2024 Feb 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from. 
6. Mayo Clinic. Finasteride (Oral Route) [Internet]. Rochester (MN): Mayo Foundation for Medical Education and Research; [cited 2025 Mar 12]. Available from.