Pharmacology · patient case question
What is the mechanism of action of adalimumab?
Patient case: Rheumatoid arthritis on a biologic agent
Patient: Female, 35 years old
Chief Complaint: “I need a filling replaced.”
Background: Rheumatoid arthritis of seven years. Adalimumab (Humira) every other week, plus weekly methotrexate with folate. No corticosteroids currently.
Vital Signs: BP 118/74 mmHg · HR 76 bpm · T 98.3°F
Findings: Symmetric swelling of the small joints of the hands with reduced dexterity. Limited opening 34 mm with bilateral TMJ crepitus. Generalized plaque accumulation, moderate gingivitis.
Show answer and explanation
Correct answer: B. It binds TNF-alpha and blocks its interaction with cell surface receptors
- A. JAK inhibition is the mechanism of the oral agents tofacitinib, baricitinib and upadacitinib — a different class with a different route.
- B. CORRECT. ADALIMUMAB is a fully human monoclonal antibody that binds TUMOUR NECROSIS FACTOR ALPHA and prevents it engaging the p55 and p75 cell surface receptors, interrupting the inflammatory cascade that drives synovitis and joint destruction. The class also includes infliximab, etanercept, golimumab and certolizumab.
- C. That describes METHOTREXATE, the other drug this patient takes. The two are frequently combined, which is why they get confused — but the mechanisms are entirely separate.
- D. CD20-directed B-cell depletion is the mechanism of RITUXIMAB, used in refractory rheumatoid arthritis and in lymphoma.
Note: The dental consequence of TNF-alpha blockade is IMMUNOSUPPRESSION. TNF-alpha is central to granuloma maintenance, so these agents raise the risk of serious infection and of TUBERCULOSIS REACTIVATION — patients are screened before starting. For dentistry: treat oral infection promptly and definitively, expect slower healing after surgery, and discuss timing with the rheumatologist before major procedures. Routine care needs no drug interruption.