Methotrexate and heartburn drugs alert
Health Canada says increase risk of side-effects from interaction 'very likely'
Labels for two types of medications — methotrexate, used to treat cancer and autoimmune disorders, and acid reducing proton pump inhibitors — will be updated to warn of a potential interaction, Health Canada says.
Using both drugs at the same time many increase the amount of methotrexate in the blood leading to side-effects, including kidney failure, low red blood cell count, inflammation of the digestive tract, irregular heartbeat, muscle pain, infections and diarrhea.
"While a definite association between PPI use and an increase in methotrexate has not been confirmed, there have been a number of studies suggesting a possible interaction between PPIs and methotrexate," the department said in a release on Friday.
"The potential for an increased risk of methotrexate side-effects is very likely, which is why Health Canada is informing Canadians and Canadian health care practitioners of this change in labelling."
Patients should not stop taking the medication unless a health care professional advises them to do so.
Proton pump inhibitors sold in Canada include:
- Dexlansoprazole (sold under the brand name Dexilant).
- Esomeprazole (sold under the brand name Nexium and its generic equivalent).
- Omeprazole (sold under the brand name Losec and its generic equivalents).
- Lansoprazole (sold under the brand name Prevacid and its generic equivalents).
- Pantoprazole (sold under the brand names Pantoloc and Panto IV, and their generic equivalent(s).
- Pantoprazole/magnesium (sold under the brand name Tecta).
- Rabeprazole (sold under the brand name Pariet and its generic equivalents).
Proton pump inhibitors are also available in combination with other drugs such as Vimovo (contains esomeprazole and naproxen).