From the Research
Yes, hypocomplementemia, specifically low C4, can be caused by medication side effects, particularly multiple immunosuppressants used to treat autoimmune diseases. The most recent and highest quality study, 1, suggests that medications such as rituximab can suppress normal immune responses, potentially affecting complement levels, including C4. This occurs because these drugs can either directly suppress complement production in the liver, increase complement consumption through immune complex formation, or alter the regulatory mechanisms of the complement system. Some key points to consider include:
- Medications like rituximab, cyclophosphamide, mycophenolate mofetil, and high-dose corticosteroids can potentially affect complement levels, including C4.
- The use of multiple immunosuppressants can increase the risk of adverse effects, including hypogammaglobulinemia and infection, as noted in 1.
- Regular blood tests to check complement levels are typically part of the standard monitoring for patients on immunosuppressive therapy for autoimmune conditions.
- It is essential to discuss low C4 levels with a healthcare provider, as it could indicate disease activity rather than medication effects, and adjustments to the medication regimen or monitoring may be necessary. Other studies, such as 2, 3, 4, and 5, provide additional information on the use of immunosuppressive drugs in autoimmune diseases, but 1 is the most recent and highest quality study relevant to the question.