Equations

Celsius to Fahrenheit Equation

((9/5) * C) + 32 = F

Fred’s Rule

(Infant age [months] / 150) * (average adult dose) = dose for infant

Young’s Rule

(Age of child [years] / Age of child [years] +12) * (avg adult dose) = dose for child

Clark’s Rule

(Weight of child [pounds] / 150 lbs) * (avg adult dose) = dose for child)

mg/kg/day:
A patient is to receive gentamicin at a dose of 5 mg/kg/day. What is the total daily dose if the patient weighs 150 lbs?

Solve the problem by understanding that we need to convert 150 lbs to kg, so do 150/2.2 to get ~68. If you then multiply 5 (mg/kg)/day by the ~68 kg, then you end up with 341 mg/day.

Dilution equation

M₁V₁=M₂V₂

Alligations:
Assuming you have a 70% solution and a 15% solution and you want to mix them to create a 30% solution. What ratios of each solution would you need?

Make a grid with 70% on the upper left, 15% in the bottom left, 30% in the middle, 15% in the upper right, and 40% in the bottom right. Use this information to do (15/(15+40)) to get the first ratio of 3/11 70% solution. Do the same for the bottom right (40/(15+40)) to get the second ratio of 8/11 15% solution. You can then multiply these ratios by a desired tangible amount to get real values.

Strange equation:
The pharmacy receives an order for 280 mL of a 5% salicylic acid solution. How much salicylic acid powder is needed to make the solution?

(Final amt grams or mL) * (% strength decimal form) = Amount of Active Ingredient

• 280 mL final solution

• 5% salicylic acid = 0.05

280 mL * 0.05 = 14 g salicylic acid powder needed.

Flow Rate

Volume / Time