Medical MathMs. Ryan

MCATC

Dimensional Analysis for Dosage Calculations

Dimensional Analysis involves setting up a series of fractions.All information is in one

problem Students do not have to

remember multiple steps

Students ask four simple questions to set up their dimensional analysis problem.

Dimensional Analysis

Review of basic math functions – Fractions and decimalsAdding SubtractingMultiplicationDivision

Students must memorize equivalents

Necessities for Student Success in Dosage Calculations

1. What is the order?

2. What do you have on hand?

3. What are you being asked to give? What is the vehicle?

4. Do you need any conversions?

The 4 Questions

The doctor has ordered the medication

Hydrochlorothiazide.The strength is 12.5 mg

The form is capsulesThe route is oral

QUESTION #1

WHAT IS THE

DOCTOR’S ORDER?

You have capsulesEach capsule is 12.5 mgThere are a total of 100 capsules in this bottle

BUT YOU ARE ONLY CONCERNED WITH WHAT YOU

NEED TO GIVE RIGHT NOW!

QUESTION #2WHAT DO YOU HAVE

ON HAND? What form

and strength of medicine is available for you to give?

You are being asked to give a capsule.

The capsule is the form of medication and the vehicle for it to get into the body!

QUESTION #3

WHAT ARE YOU BEING ASKED TO

GIVE? HOW IS IT GETTING INTO THE

BODY

The medication is ordered in mg.The medication

comes in mg.

QUESTION #4 DO YOU NEED

ANY CONVERSIONS?

Which is the most important question????

What should I pack?

How will I get there?

Who is going with me?

You are going on vacation…..

I hope you chose “How will I get there?”

1. When you set up your problem you want to know how will the medicine get to the desired location first.

In other words set the problem up by asking question 3 first.

The doctor ordered HCTZ 12.5 mg capsule to be given to the patient each morning.

How is it getting there?

? caps=

Order: Augmentin 12.5mg/kg PO every 12 hours. Child weighs 22 lbs. Pharmacy sends a 75 ml bottle of Augmentin labeled 125mg/5ml. How many milliliters will you pour from the bottle?

Complex Problems

Physicians order Daypro 1200 mg bid.

Order: Estratab 1250mcg daily

Your patient may receive Dilaudid 3 mg IM q3h for pain. Dilaudid is supplied in 1-ml ampules containing 4 mg. How many milliliters will you administer?

The physician orders heparin 2500U subq. You have heparin, 5000U per ml. How many ml will you administer?