Question

In a medication order for Phenobarbital 100 mg p.o. b.i.d., with Phenobarbital available as 50 mg per 5 mL, how many teaspoons should be administered?

Answer 1

To administer a 100 mg dose of Phenobarbital when the concentration is 50 mg per 5 mL, the patient needs 10 mL of the solution, which equals 2 teaspoons per dose, taken twice a day.

Step-by-step explanation:

To calculate the correct dosage of Phenobarbital to be administered, first establish the amount of medication needed per dose. The given medication order is for 100 mg p.o. (by mouth) b.i.d. (twice a day). The available medication concentration is 50 mg per 5 mL, which is the same as 10 mg/mL. Therefore, to administer a 100 mg dose, we need 10 mL of the Phenobarbital solution, as the calculation is 100 mg ÷ 10 mg/mL = 10 mL.

Since 1 teaspoon equals approximately 5 mL, we divide the total milliliters needed by 5 to convert to teaspoons. This results in 2 teaspoons per dose, because 10 mL ÷ 5 mL/teaspoon = 2 teaspoons. As the dosage is required twice a day, the patient will need 2 teaspoons of the Phenobarbital solution given twice daily.