The Medicines and Healthcare products Regulatory Agency (MHRA) has published a Drug Safety Update for May 2025.
This update warns clinicians of an increased risk of intrahepatic cholestasis of pregnancy (ICP) associated with thiopurines (azathioprine, mercaptopurine and tioguanine). ICP has rarely been reported in association with azathioprine therapy but the risk is believed to apply to other thiopurines. ICP may occur earlier in pregnancy when thiopurines are in use. Stopping or reducing the dose of the thiopurine drug may improve liver function tests but a case-by-case assessment is required to determine the appropriate course of action. Patients should be advised to report symptoms of ICP which include intense itching without a rash, nausea, and loss of appetite.
Action: Clinicians should be aware of this month's new guidance and implement any necessary changes to practice.