A new study has found people taking methotrexate, a common rheumatoid arthritis medicine, are not at increased risk of liver damage if they stick to fourteen units of alcohol a week or less (University of Manchester, 2017).

Methotrexate is a drug taken, often over long periods of time, to limit or prevent joint damage and disability. People who take methotrexate are often advised to abstain from alcohol as both methotrexate and alcohol are known to increase the risks of liver damage. However, it is not known whether drinking modest amounts of alcohol is safe during methotrexate therapy.

The new study by the University of Manchester, published in Annals of the Rheumatic Diseases and funded by Arthritis Research UK, has drawn upon the medical records of almost 12,000 people with rheumatoid arthritis taking the drug who had a record of the levels of alcohol they drank and who had routine blood monitoring test results. The researchers found that increased use of alcohol did indeed correspond to increased liver damage, but at fourteen units or less there was no heightened risk.

Dr Natalie Carter, Head of Research Liaison and Evaluation at Arthritis Research UK, said “We know that methotrexate can be an effective drug for treating arthritis. As it can interact with other medicines and alcohol it is important that people with arthritis have information about their medication in order to manage their arthritis safely and effectively. Arthritis Research UK invests in exceptional science to find treatments and information that let people push back the limits these conditions cause. This research adds to the knowledge we have around methotrexate and its effects in people with rheumatoid arthritis, which can help people make informed decisions about their treatment. We would recommend that people who take methotrexate to speak to their rheumatologist for advice about drinking alcohol whilst on this drug.”

Dr Jenny Humphreys, an NIHR Clinical Lecturer at the University of Manchester’s Arthritis Research UK Centre for Epidemiology, led the study. She said “In the past there’s not been clear guidance on what effects different amounts of alcohol have on these people, so doctors often err on the side of caution and recommend abstinence. As a result, some people choose to decline methotrexate so they can continue to enjoy a drink, thereby missing out on the possible benefits of the medication. Alternatively, some people may go totally without alcohol after starting methotrexate: if they like to drink in moderation, the quality of their life may be affected.”

With a pint of 5.2% ABV beer containing three units and a 250ml glass of 14% ABV wine containing 3.5 units, the findings show that people can drink in moderation, while still benefitting from the drug.

The data used in the study came from the Clinical Practice Research Datalink, a UK GP database. The researchers identified 11,839 people with rheumatoid arthritis who were taking methotrexate and had at least six liver function test results per year. Of these, five hundred and thirty developed abnormal liver function tests. Although there was no increased risk associated with drinking fourteen units or less compared to people who drank no alcohol, those who drank fifteen to twenty one units had a 33% increased probability of liver damage and this rose to 81% in the group that drank more than twenty one units.

Professor Will Dixon, Director of the Arthritis Research UK Centre for Epidemiology at the University of Manchester, who is also a rheumatologist at Salford Royal NHS Foundation Trust, believes that the results can provide important guidance for doctors who are prescribing methotrexate. He said “This is the first study to provide estimates of risk of liver damage for different levels of alcohol consumption in this drug. It also quantifies the risk for doctors so they can be clear about the extent to which different levels of alcohol will cause problems across a population of patients taking methotrexate.”