Important safety information
The CSM advice has warned that there have been reports of blood dyscrasias and liver cirrhosis with low dose methotrexate. A full blood count, renal function and LFTs should be done before starting treatment and repeated weekly until the patient is stabilised. Thereafter monitor 2-3 months. Patients should be advised to report all symptoms suggestive of infection, especially sore throat and also signs of liver toxicity, e.g. nausea, vomiting, abdominal discomfort, dark urine.
Drug safety update
December 2014: Mercaptamine and mercaptopurine: confusion between drug names
September 2020: Methotrexate once-weekly for autoimmune diseases: new measures to reduce risk of fatal overdose due to inadvertent daily instead of weekly dosing
NG100: Rheumatoid arthritis in adults: management, July 2018
CG153: Psoriasis: assessment and management, September 2017
Mercaptopurine/Methotrexate for inflammatory bowel disease should be initiated by a specialist and used according to NICE guidelines and local shared care guidelines listed below. Mercaptopurine for inflammatory bowel disease is an unlicensed use.
Shared care guideline: Mercaptopurine (Puri-Nethol®) for Inflammatory Bowel Disease
Shared care guideline: Disease Modifying Antirheumatic Drugs (DMARDs) including dermatology indications