Rheumatoid Arthritis and a Needed Extraction

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.

Correct answer: C. Creatinine clearance

• A. Incorrect. A lipid panel is relevant to cardiovascular risk management, not to methotrexate or adalimumab safety.
• B. Incorrect. Prothrombin time evaluates the extrinsic pathway and is used to monitor warfarin or assess hepatic synthetic function. Neither of her medications affects it.
• C. Correct. Methotrexate is cleared almost entirely by the kidney, so declining renal function causes drug accumulation and severe myelosuppression. Renal function assessment, alongside a complete blood count and liver enzymes, is the appropriate baseline before surgery and before prescribing any drug with renal clearance.
• D. Incorrect. Serum amylase is used to investigate pancreatitis or salivary gland disease and has no bearing on her therapy.

Note: Avoid or use caution with NSAIDs in a patient on methotrexate. NSAIDs reduce renal clearance of methotrexate and can precipitate toxicity, which makes acetaminophen the safer analgesic choice here.

Correct answer: A. Increased susceptibility to infection and impaired wound healing

• A. Correct. Both methotrexate and TNF-α blockade suppress immune function. The combination raises the risk of postoperative infection, delays healing, and can reactivate latent tuberculosis or fungal infection. Coordinate timing with her rheumatologist and consider perioperative antimicrobial coverage.
• B. Incorrect. Gingival hyperplasia is associated with phenytoin, cyclosporine, and calcium channel blockers — none of which she takes.
• C. Incorrect. Neither methotrexate nor adalimumab causes hypertensive crisis. Her blood pressure is normal.
• D. Incorrect. Neither drug produces osteosclerosis. Osteoporosis from chronic corticosteroid use would be a more plausible skeletal concern in rheumatoid arthritis.

Correct answer: C. Pseudomembranous colitis caused by Clostridioides difficile

• A. Incorrect. Tendinopathy and tendon rupture are the recognized fluoroquinolone adverse effect — ciprofloxacin and levofloxacin.
• B. Incorrect. Aplastic anemia is classically associated with chloramphenicol, which is essentially never used in dentistry.
• C. Correct. Clindamycin suppresses normal colonic flora and permits overgrowth of toxin-producing C. difficile. The result is severe watery diarrhea with abdominal cramping, which can progress to toxic megacolon. Any patient developing persistent diarrhea on clindamycin should stop the drug and seek medical care.
• D. Incorrect. Ototoxicity is characteristic of aminoglycosides such as gentamicin, and of high-dose loop diuretics.

Note: Any antibiotic can cause C. difficile colitis. Clindamycin has the strongest historical association, but broad-spectrum cephalosporins and fluoroquinolones account for more cases in absolute terms today.