Finasteride: NHS prescribing information and patient guide

Finasteride is a 5-alpha reductase inhibitor. It reduces the production of dihydrotestosterone (DHT). DHT is a hormone from testosterone.

It is licensed in the UK for two conditions.

1. Male pattern hair loss (androgenetic alopecia) at 1 mg daily:

• Finasteride 1 mg slows hair loss. It can promote regrowth in men with male pattern baldness.
• It works best for hair loss at the crown and mid-scalp.
• Results take at least 3 to 6 months to appear. You must continue use to maintain benefits.
• If you stop treatment, hair loss returns within 6 to 12 months.

2. Benign prostatic hyperplasia (BPH) at 5 mg daily:

• Finasteride 5 mg shrinks an enlarged prostate gland. This relieves urinary symptoms.
• It lowers the risk of acute urinary retention. It also reduces the need for prostate surgery.
• You usually see benefits after 6 to 12 months of continuous use.
• Doctors often prescribe it with an alpha-blocker, like tamsulosin. This gives faster symptom relief.

How does finasteride work?

The enzyme 5-alpha reductase changes testosterone into DHT. In the scalp, too much DHT makes hair follicles shrink. This leads to hair thinning and loss. In the prostate, DHT causes the gland to grow.

Finasteride blocks this enzyme. It reduces DHT levels by about 65 to 70 per cent. This treats both conditions at their hormonal root.

Finasteride's NHS availability depends on why you need it.

For benign prostatic hyperplasia (5 mg):

• Finasteride 5 mg is available on NHS prescription. This is for men with symptomatic BPH.
• It is listed in the BNF. GPs and urologists widely prescribe it.
• Generic finasteride 5 mg is very cheap. It costs only a few pence per tablet.
• Standard NHS prescription charges apply. Many patients with long-term conditions may be exempt.

For hair loss (1 mg):

• Finasteride 1 mg for hair loss is not routinely available on the NHS.
• The NHS usually sees hair loss as a cosmetic concern. Funding is not provided.
• You will need a private prescription. You can get this from your GP. They may charge a private consultation fee. You can also get it from an online prescribing service.
• The cost of finasteride 1 mg is fairly low. It is usually around 10 to 30 pounds for a month's supply from online pharmacies.

Important notes:

• Some men ask their GP for 5 mg finasteride tablets on the NHS. They then cut them into quarters to treat hair loss. Some doctors may discuss this 'off-label' use. However, it is not officially recommended. The dose you get may not be consistent.
• The Medicines and Healthcare products Regulatory Agency (MHRA) has approved finasteride 1 mg for hair loss. It is sold under the brand name Propecia and various generic versions.

Your doctor should consider several things before prescribing finasteride. This ensures the medicine is right for you.

Before starting finasteride:

• You should discuss potential side effects. These include sexual side effects and a rare risk of mood changes.
• Your doctor will assess your mental health history. This is especially true for any history of depression or anxiety.
• For BPH, you may have a digital rectal examination and a PSA blood test. This is to rule out prostate cancer.
• Your doctor will confirm you are male. Finasteride is not licensed for women.

During treatment:

• For hair loss (1 mg), routine blood tests are not needed. However, your doctor should check for side effects at follow-up.
• For BPH (5 mg), regular PSA monitoring is advised. Finasteride lowers PSA levels by about 50 per cent. This must be considered in prostate cancer screening.
• Report any mood changes, sexual problems, or breast changes quickly.

PSA and prostate cancer screening:

• Finasteride halves PSA levels. So, any PSA result during treatment should be doubled. This gives an accurate interpretation.
• An unexpected rise in PSA while on finasteride needs investigation. This is true even if the value seems normal.
• The MHRA advises prescribers and patients to know about this effect.

Duration of treatment:

• For hair loss, treatment is ongoing. You lose the benefits within 6 to 12 months of stopping.
• For BPH, long-term use is common. Your symptoms and prostate size will be reviewed periodically.

Fertility is an important concern for men of reproductive age. This is true when considering finasteride treatment.

Effects on sperm:

• Finasteride can reduce sperm count, semen volume, and sperm movement in some men.
• These effects usually reverse after stopping the medicine.
• The BNF notes these changes are often not clinically important for most men.

If you are trying to conceive:

• Discuss finasteride use with your doctor if you plan to start a family.
• Some fertility specialists suggest stopping finasteride at least three months before trying to conceive. This allows sperm to return to normal.
• There is no proof that finasteride causes birth defects when taken by the father. However, the advice is to stop if possible, as a precaution.

Handling precautions:

• Pregnant women, or those who might be pregnant, must not handle crushed or broken finasteride tablets.
• Finasteride can be absorbed through the skin. It may harm a developing male foetus. It can affect genital development.
• Intact tablets with their coating are safe to handle.

Blood donation:

• Men taking finasteride should not donate blood during treatment. They should also wait for at least one month after stopping.
• This prevents the medicine from being given to a pregnant woman through a blood transfusion.

There are other options if finasteride is not right for you. You may also prefer to explore other choices.

For hair loss:

• Minoxidil (Regaine): This is a topical treatment. You can buy it over the counter without a prescription. It works differently from finasteride. You can use it alone or with finasteride.
• Hair transplant surgery: The NHS does not offer this for cosmetic hair loss. However, you can consider it privately.
• Camouflage techniques: Scalp micropigmentation and hair fibres are non-medical choices.
• Counselling and support: If hair loss greatly affects your mental health, your GP can refer you for NHS psychological support.

For BPH:

• Alpha-blockers (tamsulosin, alfuzosin, doxazosin): These relax muscles around the prostate and bladder neck. They give faster symptom relief than finasteride.
• Dutasteride: This is another 5-alpha reductase inhibitor. It blocks both type 1 and type 2 enzymes. It is available on NHS prescription for BPH.
• Combination therapy: Finasteride or dutasteride can be combined with an alpha-blocker. This is for men with larger prostates.
• Surgical options: Transurethral resection of the prostate (TURP), laser prostatectomy, and other procedures are available on the NHS. These are for men whose symptoms are not controlled by medicine.

Your GP or specialist can discuss the best option. This will depend on your symptoms, preferences, and medical history.