A 120-pound patient has received three cartridges of 4% prilocaine, 1:200:000 epinephrine. How many more milligrams of prilocaine can this patient receive before reaching the MRD?
A) 72 mg
B) 216 mg
C) 432 mg
D) 600 mg

Question

Quizplus · Accepted Answer

The maximum recommended dose (MRD) of prilocaine is 8 mg/kg. For a 120-pound patient (which is approximately 54.5 kg, since 1 kg = 2.2 pounds), the MRD is 54.5 kg x 8 mg/kg = 436 mg. Each cartridge of 4% prilocaine contains 40 mg of prilocaine per milliliter (ml), and each cartridge is 1.8 ml, so three cartridges contain 3 x 1.8 ml x 40 mg/ml = 216 mg. Therefore, the patient can receive 436 mg - 216 mg = 220 mg more prilocaine. However, since 220 mg is not an option and the calculation was meant to find the closest option, 216 mg (option B) is the closest correct choice.

A 120-Pound Patient Has Received Three Cartridges of 4% Prilocaine