Question to the Department of Health and Social Care:

To ask His Majesty's Government how many yellow card reports of Post 5-Alpha Reductase Inhibitor Syndrome the Medicines and Healthcare products Regulatory Agency has received each year since 2019; and what medications those reports were tied to.

The Medicines and Healthcare products Regulatory Agency (MHRA) is responsible for ensuring that medicines, medical devices, and blood components for transfusion meet applicable standards of safety, quality, and efficacy. The MHRA rigorously assesses available data, including from the Yellow Card scheme, and seeks advice from the Commission on Human Medicines, the MHRA’s independent advisory committee, where appropriate, to inform regulatory decisions including amending the product information.

The MHRA has received a total of four United Kingdom reports through the Yellow Card scheme associated with the reaction term Post 5-Alpha Reductase Inhibitor Syndrome from 1 January 2019 up to and including 4 February 2026. The following table shows a yearly breakdown of reports associated with Post 5-Alpha Reductase Inhibitor Syndrome:

In addition, the following table shows a yearly breakdown of reports received by substance associated with Post 5-Alpha Reductase Inhibitor Syndrome:

Please note that each report may list more than one suspect drug. Therefore, the total number of reports received cannot be accurately derived from the figures presented in the above table.

It is important to note that anyone can report to the MHRA’s Yellow Card scheme and the recording of these reports in the Yellow Card database does not necessarily mean that the adverse reactions have been caused by the suspect drug. Many factors must be considered in assessing causal relationships, including temporal association, the possible contribution of concomitant medication, and the underlying disease. We encourage reporters to report suspected adverse reaction reports, as the reporter does not have to be sure of a causal association between the drug and the reactions, a suspicion will suffice.

The number of reports received cannot be used as a basis for determining the incidence of a reaction, as neither the total number of reactions occurring, nor the number of patients using the drug, is known.