Finasteride is for men only. It must not be taken by women, children or adolescents.
Take one tablet each day.
Your symptoms may start to improve within a few weeks, although it can take up to six months for you to notice the full benefit.
|Type of medicine||5-alpha reductase inhibitor|
|Used for||Enlargement of the prostate gland in men|
The prostate gland commonly becomes larger in older men. Prostate gland enlargement is also called benign prostatic hyperplasia (BPH). The prostate gland is situated close to the bladder, so its enlargement can cause problems with passing urine. Common symptoms that are experienced are having to wait before your urine starts to flow, taking longer at the toilet, dribbling urine, and a feeling that your bladder is not quite empty.
Finasteride works by blocking the conversion of the hormone testosterone to the more potent hormone dihydrotestosterone. It does this by blocking an enzyme called 5-alpha reductase. Dihydrotestosterone is partly responsible for making the prostate enlarge. Therefore, a reduced amount of dihydrotestosterone in the prostate causes it to shrink. This helps you to pass urine more easily.
Small doses of finasteride are prescribed for men with hair loss. A completely different brand of finasteride tablet is prescribed for men with this condition. There is more information about the tablets used for this in a medicine leaflet called Finasteride for male pattern baldness.
Before taking finasteride
Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking finasteride it is important that your doctor knows:
- If you have ever had an allergic reaction to a medicine.
- If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
How to take finasteride
- Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about finasteride and will provide you with a full list of the side-effects which you may experience from taking it.
- Take finasteride exactly as your doctor tells you to. Take one 5 mg tablet each day.
- You can take the tablet either before or after a meal, but try to take it at the same time of day each day. This will help you to remember to take your doses regularly.
- If you forget to take a dose on time, take it when you remember. If you do not remember until the following day, skip the missed dose. Do not take two doses together to make up for a forgotten dose.
Getting the most from your treatment
- Your symptoms may start to improve within a few weeks although it can take up to six months for you to notice the full benefit. This is because it takes time for the prostate gland to gradually shrink. Because of this, it is important that you continue to take the tablets regularly, even if you don't feel a benefit straightaway.
- Remember to keep your regular appointments with your doctor. This is so your doctor can check on your progress.
- Consider reducing or stopping the amount of caffeine you drink (commonly found in tea, coffee and cola) and alcohol. These can make your symptoms worse, so drinking less of these things may benefit you.
- If you are a smoker, stopping smoking may significantly improve your symptoms. This is because nicotine irritates the bladder. Ask your doctor for advice on quitting.
- Each time you collect a new supply of tablets from your pharmacy, make sure they look to be the same as you have had before. This is because there is a low-dose brand of finasteride tablet available for the treatment of a different condition. If you are unsure that you have the correct tablets, ask your pharmacist to check for you.
- Finasteride may cause harm to an unborn baby. Because of this, women who are pregnant should not handle the tablets. Also, small amounts of finasteride will be in your semen while you are taking this medicine, and it is therefore recommended that you use a barrier method of contraception (such as a condom) if your partner could become pregnant. If you need further advice about this, speak with your pharmacist or doctor.
- If you are having an operation or any medical treatment, tell the person carrying out the treatment that you are taking finasteride. This is because it can interfere with a blood test used to detect prostate cancer, so you must tell your doctor about taking finasteride if you need this test.
Can finasteride cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with finasteride. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.
|Common finasteride side-effects (these affect less than 1 in 10 men)||What can I do if I experience this?|
|Reduced desire to have sex, inability to get an erection, breast tenderness||If any of these become troublesome, speak with your doctor|
Important: if you develop any pain or lumps in your breast area, or any discharge from your nipples, you should tell your doctor. This is because there have been a few rare reports of breast cancer in men taking 5-alpha reductase inhibitors like finasteride.
In addition, there have been reports of depression in men taking finasteride, and in rare cases, thoughts of self-harming. If you develop any signs of depression whilst being treated with finasteride, stop taking it and make an appointment to see your doctor.
If you experience any other symptoms which you think may be due to the medicine, speak with your doctor or pharmacist for further advice.
How to store finasteride
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.
Important information about all medicines
Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.
If you buy any medicines, always check with a pharmacist that they are safe to take alongside your prescribed medicines.
This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
If you have any questions about this medicine ask your pharmacist.
Further reading and references
Manufacturer's PIL, Proscar® 5 mg film-coated Tablets; Merck Sharp & Dohme Limited, The electronic Medicines Compendium. Dated July 2017.
British National Formulary, 75th Edition (Mar 2018); British Medical Association and Royal Pharmaceutical Society of Great Britain, London.