Pharmacology · patient case question
What is the mechanism of action of adalimumab?
Patient case: Rheumatoid Arthritis and a Needed Extraction
Patient: 56-year-old female
Chief Complaint: “My back bottom left tooth has been aching for two weeks.”
Background: Rheumatoid arthritis for 12 years, currently in partial remission. Reports hives after amoxicillin as a teenager. No other systemic disease.
Medications: Methotrexate 15 mg weekly · Adalimumab (Humira) 40 mg subcutaneous every 2 weeks · Folic acid 1 mg daily
Vital Signs: BP 124/76 mmHg · HR 78 bpm · RR 16 · T 98.6°F
Findings: Maximum interincisal opening 32 mm with bilateral TMJ crepitus. Ulnar deviation of the fingers with metacarpophalangeal swelling. Tooth #18 with a grossly carious crown, non-restorable; extraction planned.
Show answer and explanation
Correct answer: B. Binds and neutralizes tumor necrosis factor-alpha
- A. Incorrect. IL-6 receptor blockade describes tocilizumab and sarilumab, different biologics used in rheumatoid arthritis.
- B. Correct. Adalimumab is a fully human monoclonal antibody that binds TNF-α and prevents it from engaging its receptors. This interrupts a central driver of synovial inflammation and joint destruction in rheumatoid arthritis.
- C. Incorrect. That is the mechanism of methotrexate, her other medication. Folate antagonism impairs purine and thymidylate synthesis and reduces lymphocyte proliferation — which is exactly why folic acid is co-prescribed to limit toxicity.
- D. Incorrect. CD20-directed B cell depletion describes rituximab, another biologic option but a different target entirely.
Note: The TNF-α inhibitors share the suffix -mab or the fusion-protein name etanercept: infliximab, adalimumab, golimumab, certolizumab, etanercept.