Question

A hospital pharmacist prepared thirty 100mL epidural bags containing 0.125% of bupivacaine HCL and 1mcg/mL of fentanyl citrate in 0.9% NaCl injection. How many 30mL vials of 0.5% bupivacaine HCl? How many 20mL vials of 50mcg/mL of fentanyl citrate and how many 1L bags of 0.9% NaCl were required?

Answer 1

0.125% of bupivacaine means 0.125 unit is present in 100 ml solution.

total vol = 30 x 100 = 3000 ml, so, total bupivacaine present in 3000 ml solution = 0.125/100 x 3000 = 3.75 unit

now, in 30 ml vial bupivacaine present = 30 x 0.5/100 = 0.15 unit

so, no of vial required = 3.75/0.15 = 25

fentanyl citrate:

total amount of fentanyl citrate in 3000 ml of stock is 3000 x 1 mcg

per vial fentanyl citrate present 20 x 50 = 1000 mcg,

so fentanyl citrate vial required = 3000/1000 = 3,