Question

A) An infant weighing 20 lbs is to receive Gantricin 75 mg/kg po daily in 6 divided does. Gantricin is supplied as 0.5 g/5ml. How much will you administer with each dose?

B)The physician orders diflucan (Fluconazole) 300 mg I.V.P.B. q8h. The drug is supplied as 300 mg diluted in 100 ml of D5W (300 mg/100 ml) and it is to be infused over 60 minutes. The drop factor is 20 gtts/ml. Calculate the rate in ml/hr.

C)The doctor orders the following IVs for 24 hours to infuse at 80 mL/hr: (1) 1 L D5W with 20 mEq KCl; (2) 0.5 L NS; (3) 0.5 L lactated Ringer solution. The drop factor is 15 gtt/mL. Calculate the IV flow rate in drops/minute (gtt/min).

(Show using dimensional analysis, No cursive handwriting)

Answer 1

A. Weight of infant: 20 lbs= 9.07 kg
Ordered dosage: 75mg/kg = 75 × 9.07 = 680.25 mg
Available dosage: 0.5 g/5ml = 500 mg/ 5ml
1 ml = 100 mg
Formula: ordered dosage / available dosage = 680.25 / 100 = 6.80 mg
Frequency: 6 doses per day
Answer: 6.80 / 6 = 1.13 mg

B. Ordered dosage: 300 mg
Available dosage: 300 mg / 100 ml
Time: 60 minutes
Drop factor: 20 gtts/ml
Rate: ( volume/ time ) × drop factor = (100/60) 20 = 1.66 × 20 = 33 drops / min
Answer: 33 drops per min

C. Volume: 80 ml / hr
Time: 24 hours = 24 × 60 = 1440 mins
Drop factor: 15 gtts/ ml
Rate: (volume / time) × drop factor = (80/1440) × 15 = 0.055 = 0.83
Answer: 1 drop per min