Sarilumab (Kevzara): What You Need to Know

What is sarilumab?

Sarilumab (brand name Kevzara) is a biologic medication used to treat polymyalgia rheumatica (PMR) and rheumatoid arthritis (RA). It is the first and only biologic FDA-approved for PMR, where its primary role is helping patients taper off prednisone faster and with less risk of flare.

Sarilumab is an IL-6 receptor inhibitor. Interleukin-6 (IL-6) is one of the key inflammatory proteins driving the pain, stiffness, and elevated inflammatory markers in PMR and RA. By blocking the IL-6 receptor, sarilumab shuts down that inflammatory signal and allows your body to function without the constant support of corticosteroids.

How to take it

• 200 mg subcutaneous injection every 2 weeks — same dose for both PMR and RA
• Self-administered at home using a prefilled syringe or prefilled pen after training in our office
• Store in the refrigerator (36–46°F) in the original carton — do not freeze or shake
• Remove and let it warm to room temperature before injecting — about 30 minutes for the syringe, 60 minutes for the pen
• Rotate injection sites between the thigh and abdomen (at least 2 inches from the navel) — avoid areas that are bruised, red, hard, or scarred

For PMR, sarilumab is started alongside a tapering course of prednisone. The goal is to taper off steroids over roughly 14 weeks while sarilumab takes over as the primary treatment — then continue sarilumab alone.

What to expect when starting

Most patients notice improvement within the first 2–4 weeks, though you may not feel the full benefit until you’ve been on it for 2–3 months. The earliest sign that it’s working is often that your stiffness and inflammatory markers improve even as prednisone is being tapered down.

In the SAPHYR trial — the study that led to FDA approval for PMR — patients on sarilumab used roughly 60% less prednisone over a year compared to those without it. That reduction in steroid exposure is the main reason to use this medication: less prednisone means lower risk of weight gain, bone loss, elevated blood sugar, and the other side effects that accumulate with prolonged steroid use.

Lab monitoring

Sarilumab requires regular lab monitoring because it can affect your blood counts, liver enzymes, and cholesterol:

• Complete blood count (CBC) — monitors neutrophils (infection-fighting white blood cells) and platelets. Neutropenia is the most common lab abnormality with sarilumab. Low counts may require holding a dose or adjusting.
• Liver function tests (ALT/AST) — checked every 4–8 weeks initially, then every 3 months. Sarilumab can raise liver enzymes.
• Lipid panel — sarilumab commonly raises cholesterol levels, a class effect of IL-6 blockers. Checked 4–8 weeks after starting, then managed with a statin if needed.

Important: Like all IL-6 blockers, sarilumab suppresses CRP and can blunt fever. This means your usual warning signs during an infection may be masked. Don’t rely on “I don’t have a fever” or “my CRP was normal” as reassurance — contact us if you feel unwell.

Side effects to watch for

Common:

• Injection site reactions — redness, itching, or mild swelling at the injection site; usually mild and short-lived
• Upper respiratory infections — cold symptoms, sinus congestion
• Elevated cholesterol — monitored with blood work, treated if needed
• Neutropenia — low neutrophil count on labs, usually without symptoms; we monitor and adjust dosing accordingly

Contact us if you experience:

• Fever, chills, or signs of infection — persistent cough, burning with urination, wound that isn’t healing, or feeling generally unwell (remember, fever may be blunted)
• Severe abdominal pain — sarilumab may increase the risk of gastrointestinal perforation, particularly in patients with a history of diverticulitis
• Unusual fatigue, dark urine, or yellowing of the skin/eyes — signs of liver injury
• Easy bruising or unusual bleeding — could indicate low blood counts

Required screening before starting

Before your first dose, we will check:

• TB screening (QuantiFERON blood test) — biologics can reactivate latent tuberculosis
• Hepatitis B and C screening — to rule out chronic viral hepatitis
• Baseline labs — CBC with differential, metabolic panel, and liver function tests
• Lipid panel — to establish your baseline cholesterol levels
• Review of your vaccination history — certain vaccines should be given before starting

Things to avoid

• Live vaccines — including live shingles vaccine (Zostavax), live nasal flu spray, and MMR. Inactivated vaccines (flu shot, COVID, Shingrix) are safe and recommended.
• Other biologics — sarilumab should not be taken with another biologic medication. Combining biologics significantly increases infection risk.
• Don’t ignore infections — and remember that your usual warning signs (fever, elevated CRP) may be suppressed. When in doubt, call us.

Drug interactions to know about

IL-6 normally slows down certain liver enzymes (called CYP450 enzymes) that metabolize many common medications. When sarilumab blocks IL-6, those enzymes speed back up, which can lower the levels of some drugs in your blood. This matters most for medications with a narrow dosing window — particularly warfarin, theophylline, and oral contraceptives. Let us know about all your current medications so we can monitor and adjust if needed.

Frequently asked questions

How is sarilumab different from tocilizumab (Actemra)? Both are IL-6 receptor blockers and work through the same mechanism. The key difference is practical: sarilumab is subcutaneous only (no IV option), while tocilizumab comes in both IV and subcutaneous forms. Sarilumab is the only one with a specific FDA approval for PMR, though tocilizumab is sometimes used off-label for PMR as well.

Will I be on sarilumab forever for PMR? Not necessarily. PMR often burns out over 1–3 years. Once you’ve been in stable remission on sarilumab for a sustained period, we’ll discuss whether it’s reasonable to try spacing out doses or stopping. There’s no fixed timeline — we make that decision based on your symptoms and inflammatory markers.

Can I take sarilumab without methotrexate? Yes. For PMR, sarilumab is used as monotherapy — methotrexate is not part of the standard regimen. For RA, it can be used alone or combined with methotrexate or other conventional DMARDs, depending on your situation.

What if I miss a dose? If you miss your scheduled injection by a day or two, take it as soon as you remember and resume your regular every-2-week schedule. If it’s been significantly longer, call us for guidance on when to restart.

Can I take sarilumab during pregnancy? Data on sarilumab in pregnancy is limited. Current guidelines recommend stopping sarilumab before a planned pregnancy when possible. If you’re thinking about starting a family, let us know well in advance so we can plan a transition.

This handout is provided for educational purposes and does not replace individualized medical advice. Always follow the specific instructions given by your rheumatologist.