When your immune system goes haywire, it doesn’t just fight germs—it starts attacking your own tissues. That’s where complement inhibitors, drugs that block specific parts of the immune system’s complement cascade to prevent tissue damage. Also known as C5 inhibitors, they’re not your typical anti-inflammatories. They’re precision tools designed to shut down a specific pathway that, when overactive, destroys red blood cells, nerves, or kidney filters. Unlike broad immunosuppressants that weaken your whole defense system, these drugs target just one broken part—like turning off a faulty alarm without disabling your entire security system.
Complement inhibitors are now used for conditions you might not expect. For example, paroxysmal nocturnal hemoglobinuria (PNH), a rare blood disorder where the immune system destroys red blood cells, responds dramatically to these drugs. Patients who once needed frequent blood transfusions now live normal lives. Similarly, myasthenia gravis, a neuromuscular disease where antibodies attack nerve-muscle connections, sees fewer muscle weakness episodes when complement inhibitors are added to treatment. Even rare kidney diseases like C3 glomerulopathy and atypical HUS are now managed with these targeted therapies, reducing the need for dialysis.
These drugs don’t work for every autoimmune condition. They’re not used for rheumatoid arthritis or lupus—at least not yet. But for the diseases where the complement system is clearly the main culprit, they’re game-changers. The most common ones, like eculizumab and ravulizumab, are given by IV, while newer oral versions are in development. Side effects exist—mainly increased risk of meningococcal infections—which is why vaccination is required before starting. But for many, the trade-off is worth it: fewer hospital visits, less pain, and more control over their health.
What you’ll find in the posts below are real-world stories and data about how these drugs fit into broader treatment plans. You’ll see how they compare to older therapies, what patients actually experience, and why some doctors still hesitate to use them. You’ll also find connections to other immune-modulating drugs like ACE inhibitors and ARBs, which protect organs in different ways, and how newer biologics are reshaping how we think about immune system control. This isn’t just about one class of drugs—it’s about how medicine is shifting from blanket suppression to surgical intervention inside the immune system.
Myasthenia gravis is an autoimmune disorder causing muscle weakness. Learn the latest treatments - from pyridostigmine and thymectomy to FDA-approved biologics like FcRn inhibitors - and how to navigate cost, access, and long-term management.
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