Answer :
Final answer:
To determine the patient's dosage per dose, the weight in pounds is first converted to kilograms, and then multiplied by the prescribed mg/kg/day. This total is then divided by two since the medication is to be taken twice daily, resulting in 18.7107 mg per dose.
Explanation:
To calculate the dosage of isotretinoin for a patient weighing 165 pounds, we must first convert the patient's weight to kilograms, because the dosage is prescribed in milligrams per kilogram.
Since 1 pound is equal to 0.453592 kilograms, we multiply 165 pounds by 0.453592 to convert it to kilograms. 165 pounds * 0.453592 = 74.8428 kilograms.
Next, we calculate the daily dosage by multiplying the patient's weight in kilograms by the prescribed amount, 0.5 mg/kg/day: 74.8428 kg * 0.5 mg/kg = 37.4214 mg/day.
The prescription states the daily dose should be divided and given BID (which means twice a day), so we divide the total daily dose by 2 to find the dosage per dose: 37.4214 mg/day ÷ 2 = 18.7107 mg per dose.
