MHRA Alert – Thiopurines and Intrahepatic Cholestasis of Pregnancy

Safety Update: Thiopurine Use in Pregnancy

The MHRA has issued a safety update regarding a rare but serious risk associated with thiopurine medications in pregnant patients.

What You Need to Know

Intrahepatic cholestasis of pregnancy (ICP) has been rarely reported in patients treated with azathioprine and is believed to be a risk applicable to all drugs in the thiopurine class. ICP is a liver condition that can develop during pregnancy and may pose risks to both mother and fetus if not managed appropriately.

Affected Medications

• Azathioprine
• Mercaptopurine
• Other thiopurine-class drugs

Recommended Actions

For prescribers: Review the use of thiopurines in women of childbearing age and pregnant patients. Consider the risks and benefits carefully, and ensure appropriate monitoring and counselling.

For clinicians and responders: Be aware of this association when assessing pregnant patients on thiopurine therapy, particularly if presenting with symptoms consistent with cholestasis (pruritus, jaundice, or abnormal liver function).

Further Information

For the full MHRA safety update, visit the MHRA Drug Safety Update page.