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Anesthesia · single question

What is the maximum number of cartridges of 4% articaine with 1:100,000 epinephrine that can be administered to a 7-year-old child weighing 25 kg?

  1. 3
  2. 2
  3. 4
  4. 1
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Correct answer: B. 2

Articaine maximum dose: 7 mg/kg (safe pediatric dose). Child weight = 25 kg. Maximum dose = 7 × 25 = 175 mg. Each 1.8 mL cartridge of 4% articaine = 4% × 1800 mg/100 mL = 72 mg per cartridge. Number of cartridges = 175 ÷ 72 = 2.43 → round DOWN = maximum 2 cartridges (144 mg, well within 175 mg limit).
  • A. INCORRECT. Three cartridges = 216 mg, which exceeds the 175 mg maximum for a 25 kg child.
  • B. CORRECT. Maximum calculation: 7 mg/kg × 25 kg = 175 mg maximum. Each cartridge of 4% articaine = 72 mg. 175 ÷ 72 = 2.43 → maximum = 2 cartridges (144 mg total, within the 175 mg limit).
  • C. INCORRECT. Four cartridges = 288 mg — grossly exceeds the safe maximum dose and risks local anesthetic toxicity.
  • D. INCORRECT. One cartridge (72 mg) is safe but not the MAXIMUM. The child can safely receive up to 2 cartridges.

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