Men taking popular hair-loss drugs have been warned of their potential serious sexual and psychological side-effects by the UK’s drug safety watchdog.
The Medicines and Healthcare products Regulatory Agency (MHRA) said men taking finasteride – a daily pill used to treat male pattern baldness – need to be aware that the drug has been linked to sexual dysfunction and mood disorders.
Dutasteride, a similar drug used to treat symptoms of an enlarged prostate, has also been slapped with a precautionary warning.
In 2024, the watchdog ordered suppliers of finasteride to include a patient alert card in packs of the drug to raise awareness of the risks, which remain in place.
These cards highlight the potential risk of erectile dysfunction, loss of libido, depression and suicidal thoughts and advise hair loss patients to stop the drug immediately if they develop symptoms.
Those taking the drug for an enlarged prostate who experience symptoms should contact their doctor urgently.
Dr Alison Cave, chief safety officer, said: ‘Following an additional detailed review of the evidence, we have now strengthened product information for both finasteride 1mg and dutasteride to provide clearer guidance on these potential risks and to support informed discussions between healthcare professionals and patients.’
Finasteride, sold under the brand names Proscar and Propecia, is used to treat both conditions, but is only available on the NHS for enlarged prostate.
Men on popular hair-loss drug are being warned of sexual and psychiatric side effects
It works by blocking the sex hormone testosterone from turning into dihydrotestosterone (DHT), which can encourage the prostate to grow and hair to fall out.
An enlarged prostate is a common condition in men over the age of 50 and is not usually serious. But as the prostate swells it can put pressure on the urethra, causing difficulty urinating.
Common symptoms include a weak flow of urine, taking longer than usual to empty your bladder and needing to go more urgently, including in the night.
Finasteride has long been linked to mood disorders and sexual dysfunction, but now the MHRA has revised all available evidence to ensure patient safety.
Dr Cave added: ‘Patient safety is our top priority.
‘We expect prescribers to discuss the relevant safety information with patients so they can make informed decisions about their treatment, and we continue to encourage patients and healthcare professionals to report suspected side effects through the Yellow Card scheme.’
The regulator said its Yellow Card scheme, designed to allow patients to report adverse effects of medicines, had received 170 suicidal ideation and related terms for finasteride. Of these, 19 were fatal.
After reviewing all of the reports made to the scheme, experts have concluded that stopping the drug does not necessarily dissipate side-effects, with sexual dysfunction sometimes persisting after treatment is stopped.
Previously the MHRA encouraged patients to share the alert card with friends and family who may better notice changes in mood.
Prescribing data suggests more than 400,000 prescriptions per month are issued for finasteride 5mg and dutasteride containing medicines.
But finasteride 1mg is not currently prescribed on the NHS and is only available by private prescription, meaning accurate prescription numbers are not available.
