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Finasteride (for Benign Prostatic Hyperplasia)

Medication Information Leaflet

What is this medication for?

It is used to treat benign prostatic hyperplasia (enlarged prostate), a non-cancerous growth of the prostate gland, caused by overproduction of a hormone called dihydrotestosterone. It lowers dihydrotestosterone, and thus shrinks the prostate and relieves the symptoms. Therefore, this medication is for use in men only. It may take up to 6 months or more for you to notice an effect.

As the prostate enlarges, it can lead to urinary problems such as difficulty in passing urine and frequent visits to the toilet. It can also cause the flow of urine to be slower and weaker. If left untreated, there is a risk that the urine flow may be completely blocked (acute urinary retention) and this requires immediate medical treatment.

This medication may also be used for other conditions. Check with your healthcare professional if you are unsure why you are given this medication.

How should I take or use this medication?

Do not stop taking your medication without checking with your healthcare professional.
You may take this medication with or without food.
This medication should be swallowed whole.
This medication should not be touched or handled by pregnant women or women who are of childbearing age as the active ingredient of the medication (Finasteride) can be absorbed through the skin. If contact with the tablet occurs, wash the area immediately with soap and water as the medication may negatively affect the development of the fetus.

What should I do if I forget to take or use this medication?

If you forget to take a dose, take it as soon as you remember. Then take your next dose at the usual time. Do not take two doses to make up for the missed dose.

What precautions should I take when taking or using this medication?

Use a condom during sexual intercourse as your semen could contain the medication. If your partner is or may be pregnant, you must avoid exposing her to your semen as it may affect the normal development of the baby’s sex organs.
Avoid donating blood during treatment or for 1 month after you stopped the treatment as there may be a risk that your blood may be given to a pregnant female transfusion recipient.

Inform your healthcare professional if:

You are allergic to this medication or any of the other ingredients of this medication
You have heart or liver problem
You are taking this medication as it may affect prostate specific antigen (PSA), a lab test to monitor the effectiveness of the medication as well as the condition.

What are some common side effects of this medication?

Unable to get or keep an erection firm enough to have sexual intercourse
Decreased libido (sex drive); less desire to have sex
Difficulty with ejaculation

These side effects may disappear after a while if you continue to take the medication. If not, they usually go away after stopping the medication. Discuss with your doctor if you are unsure or these side effects become bothersome to you.

What are some rare but serious side-effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following:

Swollen face/eyes/lips/tongue
Difficulty in breathing
Itchy skin rashes over your whole body

Changes in your breast tissue such as lumps, pain, enlargement or nipple discharge.
Pain in your testicle

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What food or medication should I avoid when I take or use this medication?

Inform your healthcare professional if you are taking or intend to take any other medication, supplements, traditional medications or herbal remedies.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children, pregnant women and women who are of childbearing age.

How do I throw away this medication safely?

Pack this medication into a black trash bag and seal it tightly before throwing into the rubbish chute or bin.

Disclaimer

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on September 2019

This article was last reviewed on Wednesday, June 16, 2021