Client with new-onset seizures of unknown cause is started on phenytoin. the health care provider has ordered a loading dose of 15 mg/kg iv to be given at a rate of 40 mg/min. what is the loading dose in milligrams if the client weighs 176 lb (80 kg)? record your answer using a whole number

Think about it in terms of ratios, i.e. the ratio of dosage to mass;
So if 15 mg is given for every kg of mass, the ratio is:
15:1

We know the client weighs 80 kg, so we need to adjust (by multiplication or division only) the right-hand side number (as this represents mass) to get 80;
So in order to turn 1 (i.e. the right-hand side) into 80, we multiply by 80;
We must ∴ also multiply 15 (i.e. the left-hand side) by the same number (i.e. 80) to get the correlating dosage;
So:
15 × 80 = 1200
Therefore, the ratio is:
1200:80
And so the leading dosage is 1200 mg for a person of 176 lb or 80 kg.