Question

The dose of a drug is 120 mg/kg/d, infused over 24 hours. What would be the infusion rate, in milliliters per hour, of a 2.5% (w/v) solution of the drug if administered to a patient weighing 176 lb? Round your final answer to the nearest tenth.

Answer 1

Solution:-

Given,

dose of a drug : 120 mg/kg/d, infused over 24 hours.

So, infusion time = 24 hr

patient weight= 176 lb

Now, 1 lb = 0.454 Kg

Or, 176 lb = 0.454 × 176 Kg

=79.90 Kg

Hence, patient's weight (kg) = 79.90 kg

Overall dose for the patient = dose × weight of patient

= 120 mg/Kg/day × 79.90 kg

= 9588 mg/day

= 9.588 g/day

Now, concentration of drug = 2.5 % (w/v)

It means 2.5 g of drug present in 100 ml solution.

Using unitary method:-

2 .5 g of drug present in 100 ml solution

1 g of drug present in =100/2.5 ml solution

9.588 g of drug present in = (100/2.5) × 9.588 ml solution

= 383.52 ml solution

Now, volume of solution = 283.52 ml

Infusion rate (ml/hr) = volume of solution in ml/ infusion time in hr

= 383.52 ml/24 hr

= 15.98 ml/hr

= 16.0 ml/hr [ rounded to nearest tenth]

Therefore, infusion rate = 16.0 ml/hr