Final answer:
After converting Jacob's weight from pounds to kilograms, the calculated dose of Captopril is 32.658624 mg/day, which rounds to 33 mg/day. The closest provided option is 32 mg/day.
Step-by-step explanation:
To calculate the optimal dose of Captopril for Jacob, an 18 lb. infant, given the dosage of 4 mg/kg/day, we first need to convert Jacob's weight from pounds to kilograms. Since 1 pound is equal to 0.453592 kg, Jacob's weight in kilograms is 18 lb × 0.453592 kg/lb = 8.164656 kg.
Next, we calculate the daily Captopril dose by multiplying the weight in kilograms by the dosage rate:
8.164656 kg × 4 mg/kg/day = 32.658624 mg/day
When rounding to the nearest whole number, Jacob's optimal dose is 33 mg/day, which is not one of the options provided. However, the closest option to the calculated dose is 32 mg/day, which is option B.