Does methotrexate increase the risk of infections?
Methotrexate can increase infection risk because it suppresses parts of the immune system, making it harder to fight off germs. That means people taking methotrexate—especially at higher doses or with other immune-suppressing medicines—may get infections more easily and can sometimes get more serious infections.
What kinds of infections are most associated with methotrexate?
Clinically, the infections seen in people on methotrexate are usually those caused by common bacteria and viruses (like respiratory and urinary infections). More serious opportunistic infections are less common, but they can happen, particularly when methotrexate is combined with other immune-suppressants (for example, corticosteroids or biologic agents).
How much does the risk depend on the dose and your overall treatment?
Risk tends to be higher when:
- Methotrexate is used at higher doses (compared with low doses used for some inflammatory conditions).
- You also take other drugs that affect immunity (such as steroids).
- You have other factors that already increase infection risk, such as older age, diabetes, chronic lung disease, kidney disease, or prior serious infections.
When should someone on methotrexate contact a clinician urgently?
Get medical advice promptly if you develop signs of infection, such as fever, chills, shortness of breath, worsening cough, burning with urination, significant sore throat, or rapidly worsening symptoms. Serious infections can progress quickly in people whose immune response is suppressed.
Can you reduce infection risk while taking methotrexate?
Common risk-reduction steps include:
- Staying up to date on recommended vaccinations (using non-live vaccines when appropriate).
- Practicing routine hygiene and avoiding close contact with people who are actively sick.
- Monitoring blood counts and liver/kidney function as clinicians recommend, since abnormal results can affect how safely methotrexate is continued.
Do patients ask about “methotrexate and tuberculosis” or other rare infections?
Because methotrexate suppresses immune function, clinicians often screen for certain latent infections before starting it or when risk factors exist (for example, tuberculosis testing is commonly considered in patients with relevant history). The goal is to prevent reactivation when immune defenses are weakened.
What’s the bottom line?
Yes. Methotrexate can increase the risk of infections by lowering immune defenses. The likelihood and severity of infections depend on dose, other medications used alongside methotrexate, and individual health risk factors.