Calculate the volume (mL)

Question

She is prescribed 0.15 mg/kg of morphine. The concentration on the bottle is 5mg/mL. Calculate the volume (mL) of morphine to be administered.

Answer 1

We need the weight of the patient. Let us assume it is the same patient as before and the weight = 54.55 kg.

Use dimensional analysis and end up with volume in mls.

54.55 kg x 0.15 mg / kg x 1 ml / 5 mg = 1.64 mls = 2 ml (1 sig. fig. based on 5 mg/ml)

... note that kg units cancel; mg units cancel; left with mls ...