UK regulator tightens finasteride warnings and adds precaution for dutasteride over psychiatric and sexual side effects

The U.K.’s medicines regulator has tightened safety warnings for finasteride and added a new precautionary warning for dutasteride over psychiatric side effects and sexual dysfunction, telling prescribers to discuss the risks with patients and monitor them during treatment.

In updated advice published Monday, the Medicines and Healthcare products Regulatory Agency said product information for finasteride will be strengthened to reflect the medicine’s association with depression, suicidal ideation and sexual dysfunction, which may persist after treatment stops. For finasteride 1 mg, which is used for androgenetic alopecia, or male pattern hair loss, the Summary of Product Characteristics and patient leaflet will be updated to clarify that sexual dysfunction may contribute to mood disorders and has been reported both with and without mood changes. For dutasteride 0.5 mg, the regulator will add precautionary wording stating that mood alterations have been reported with finasteride, a medicine in the same class.

The MHRA told prescribers to discuss those risks when starting treatment, review patients’ medical and psychiatric history, and monitor patients while they are taking the medicines. It also gave different advice depending on the product. People taking finasteride 1 mg should stop treatment immediately if they develop depression or suicidal thoughts, the agency said. People taking finasteride 5 mg or dutasteride should contact a health care professional if they develop those symptoms.

The agency said Yellow Card reports of suspected side effects from 1994 through May 31, 2025, included 170 reports of suicidal ideation and related terms for finasteride, covering both 1 mg and 5 mg tablets, and five such reports for dutasteride 0.5 mg. It also recorded 19 fatal reports of suicide for finasteride and none for dutasteride. The MHRA stressed that Yellow Card reports do not prove causation and require careful analysis. The medicines are widely used: prescribing data suggests more than 400,000 prescriptions a month are issued for finasteride 5 mg and dutasteride-containing medicines. The regulator said finasteride 1 mg is not routinely prescribed on the NHS and is mostly supplied privately, so exact use of the hair-loss dose is not available from NHS prescribing data.

The update follows MHRA consideration of a European regulatory review carried out under Article 31. That review concluded that suicidal thoughts should be listed as a side effect of finasteride tablets, but it did not establish a direct causal link for dutasteride. The MHRA’s action is a label-warning and risk-mitigation update, not a withdrawal, and both medicines remain authorized for their approved uses.

“The MHRA has taken significant action to raise awareness of the risks of sexual dysfunction, depression and suicidal thoughts associated with finasteride, including issuing a Drug Safety Update and introducing patient alert cards in 2024. … 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,” said Dr. Alison Cave, the MHRA’s chief safety officer. The patient alert cards introduced for finasteride in 2024 will remain in place, and 1 mg packs will continue to include a patient card.