# 02.07 Interactive Pharmacology Practice

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## Outline

### Overview

Pharmacology is hard! So let’s practice some problems together!

### Nursing Points

#### General

1. Tips and Tricks for success
1. See what the question is asking
1. Unit of measurement
2. What’s the order?
1. Dose
2. Frequency
3. Is there a conversion needed?
1. Example: g to mg, lbs to kg
2. Keep everything labeled!
1. Unit of measurement
4. Double-check that the answer is labeled
5. Is this what the question is asking for?
6. Did you round correctly?
2. Oral and IM medications
1. Oral medications
1. Pill
2. Liquid
2. IM medications
1. Intramuscular
2. Given in
1. Deltoid
1. Do not exceed 2ml
2. Ventrogluteal
1. Midway between the hip and head of femur
2. Do not exceed 2.5ml
3. Vastus lateralis
2. Do not exceed 5ml
4. Dorsogluteal
1. Gluteus maximus
2. Not recommended
1. Sits close to sciatic nerve and gluteal artery
3. Do not exceed 4ml
3. Dosage calculation
1. Basic formula
1. Desired/Have x Vehicle = Amount to give
1. Desired = ordered dose
2. Have = what’s on hand
3. Vehicle = how the drug comes
1. Tablet
2. Liquid
3. Capsule
2. Example
1. Solve
1. Order: Erythromycin 0.5g po q8h. Available: Erythromycin 250mg. How many tabs does the patient get per dose?
2. See units of measurement
1. Don’t match!
1. Convert!
1. Always convert to what’s on hand
2. 0.5g to mg = 500mg
3. Use basic formula
1. D/H x V = 500mg/250mg x 1 tab
2. Answer: 2 tabs per dose
2. Formulas using body weight
1. Convert lbs to kg or vice versa
2. Find dose per body weight
1. Multiply dose x body weight x frequency
3. Use basic formula
4. Example
1. Solve
1. Order: Cefaclor 20mg/kg/day in three divided doses. Available: Cefaclor 125mg per 5ml. How many mls should the patient get per dose with a weight of 20 lbs?
2. See units of measurement
1. Weights don’t match
1. Convert!
1. Convert to desired weight
2. Remember 1kg = 2.2lbs
1. When you’re given pounds, divide DOWN!
3. 20 lbs/2.2lbs/kg = 9 kg
3. Find dose per body weight
1. Dose x body weight x frequency
1. 20mg x 9kg x 1 day = 180mg per day
4. Check the question again
1. We are looking for each dose, not daily
5. Use basic formula
1. Desired/Have x Vehicle
1. 60mg/dose/125mg x 5ml = 300mg/ml/125mg
2. Final Answer: 2.4 ml TID
3. Intramuscular calculations
1. Follow same basic formula rules
2. Example
1. Solve
1. Order: Gentamycin 60mg IM. Available drug: Gentamycin 80mg/2ml in a vial. How many mls will the patient receive?
2. Check doses and conversions
3. Use basic formula
1. Desired/Have x Vehicle
2. 60mg/80mg x 2ml = 120mg/ml/80mg
2. Solve
1. Order: Naloxone 0.5mg IM STAT. Availalbe Naloxone 400mcg/ml. How much should you give?
2. Check doses and conversions
1. Don’t match!
1. Change to what’s on hand
1. 0.5mg = 500mcg
3. Basic formula
1. Desired/Have x Vehicle
2. 500mcg/400mcg x 1ml
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## Transcript

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Today we’re going to be doing some interactive pharm practice. You will hear the problem and do your math and then we will check it together.

We are going to go over some basic tips for success and do some practice problems together. You will hear the problem, pause and do your math and meet me back to go over the math.

Let’s take a quick look at the medication routes we’ll be working with. Oral medications we know are usually pill or liquid form. Pretty cut and dry there. Intramuscular injections is where things can get a little tricky, particularly when we’re talking about maximum doses to give in the syringe. So here are the 3 recommended sites. We have the deltoid, ventrogluteal and vastus lateralis. Simply put, your upper arm, midway between the hip and femur and the quads, in that order. We also have the dorsogluteal muscle, which is the buttocks, but it’s not an ideal spot because it sits so close to the sciatic nerve and the gluteal artery. The biggest thing you want to know is the maximum amount of medication you are allowed to give in each place.  In the deltoid, we cannot inject more than 2ml of medication. In the ventrogluteal, do no exceed 2.5ml, and in the vastus lateralis, don’t exceed 5ml. If you must use the dorsogluteal muscle, the max is 4ml.

So enough of the technical stuff, let’s do some math! First we will work with basic formula. There are several different methods out there but basic formula is exactly as advertised: basic and straightforward. It’s simply Desired over Have times Vehicle (D/H x V) equals the amount to give. Desired is the ordered dose, Have is what you have on hand and Vehicle is how the drug comes so tablet, liquid or capsule. Most of what we do in this lesson is going to use this formula at some point.