Question

Order: Cardizem ( diltiazem ) 150 mg in 100 mL D5W at 10 mg / hr IV .
Available: Infusion pump, vial of Cardizem labeled 5g / mL

What is the rate?

Answer 1

Ans. Part 1: Preparation of 150 mg in 100 mL D5W

Given, stock solution- 5.0 g/mL

Using, C1V1 = C2V2       -- equation 1

where

C1= Concentration of initial solution 1, V1= volume of initial solution 1      ;( stock solution)

C2= Concentration of final solution 2, V2= volume of final solution 2 ;(diluted solution)

5.0 g x V1 = 0.150 g x 100 mL                             ; [150 mg = 0.150 g]

Or, V2 = (0.150 g x 100 mL) / 5.0 g = 3.0 mL

Preparation: Add 3.0 mL of the stock solution to 97.0 mL D5W to make 100mL of 150 mg Cardizem.

Part 2: Flow rate of 10 mg/hr IV

            150 mg Cardizem is present in 100 mL

            Or, 1 mg           -           -           (100 /150) mL

            Or, 10 mg          --          -           (100 /150) x 10 mL

                                                            = 6.66 mL

So, 10 mg Cardizem is present in 10 mL diluted solution.

Thus, the desired flowrate = 6.66 mL / hr.