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Further information on psychiatric and sexual side effects is to be added to product information for medicines containing finasteride and dutasteride, the Medicines and Healthcare products Regulatory Agency (MHRA) has announced.
In a drug safety update published on 11 May 2026, the MHRA said it had reviewed evidence for both drugs and recommended further measures to minimise risks.
Both finasteride and dutasteride are used in the treatment of benign prostatic hyperplasia. Finasteride is also used to treat male pattern hair loss, while dutasteride is used in the treatment of acute urinary retention.
In the drug safety update, the MHRA says that patients prescribed finasteride-containing medicines are known to experience depression, suicidal ideation and sexual dysfunction, which may persist after the treatment is stopped.
The MHRA confirmed that the summary of product characteristics and patient information leaflet for finasteride 1mg will be updated “with a warning that sexual dysfunction may contribute to mood disorders, which has been reported in some patients, and sexual dysfunction has also been reported without mood alterations”.
Owing to its similarity to finasteride, the MHRA said that warnings will be added to dutasteride’s product information “as a precaution” to note that depressed mood, depression or suicidal ideation have been reported with another medicine in the same class (i.e finasteride).
The drug safety update cited prescribing data that suggest that more than 400,000 prescriptions per month are issued for finasteride 5mg and dutasteride-containing medicines. Finasteride is only available privately, which means that accurate prescription numbers are not available.
In 2024, the MHRA issued a drug safety update on finasteride to remind healthcare professionals of the psychiatric and sexual side effects associated with the drug. It also introduced patient cards to be given to patients prescribed the treatment.
In April 2026, the MHRA reported that finasteride was among more than 130,000 doses of unauthorised medicines seized from a flat in Bolton, Greater Manchester, from which unauthorised medicines were being stored, packaged and distributed by mail order.
