1. Oral Dosage of Drugs
Chapter 10
MAT 119

2. Medication Administration
Medication administration is the way that a drug is introduced into the body.
The route of administration is chosen according to the speed of absorption desired and the site of action of the medication.
Some medications are formulated for a specific route only and must be given in that manner. It is important that medicines be administered as directed by the manufacturer.

3. Oral Medication Administration
Oral and enteral administration require that the medication not be destroyed by the environment of the stomach and digestive enzymes.
It is too slow if rapid absorption is required, and cannot be used if the patient is vomiting.
Rectal administration in the form of liquids or suppositories circumvents this problem in enteral administration.

4. Oral Medications
Oral drug forms are generally the easiest for the patient to take and the most convenient for the nurse to administer.

5. Oral Medications Oral medications come in a variety of forms Tablets
Powered drugs compressed or molded into solid shapes. Plain tablets may be crushed for easier swallowing.
Scored tablets
Have a line down the center so the tablet can be broken into halves
Unscored tablets should not be broken because there is no certainty that the drug is evenly distributed.

6. Pill Cutter & Pill Crusher

7. Oral Medications Capsules
Gelatin containers holding a drug in solid or liquid form.
For patients with difficulty swallowing, the nurse can open and put the semisolid in applesauce or custard – should check to see if medication is available as a liquid.
Some are enteric-coated or contain particles of the drug that are coated to dissolve at different times. These are long-acting and should NOT be opened (time-release or sustained-release). (Can not crush or open to put in applesauce.)

8. Oral Medications Coated tablets (film-coated) Enteric-coated tablets
Smooth and easy to swallow because of their coating. Some tablets may be crushed.
Enteric-coated tablets
Dissolve in the more alkaline secretions of the intestine rather than in the highly acidic stomach juices.
Reduces the chances of gastric mucosa irritation.
Should NOT be crushed!

9. Oral Medications Prolonged-release or extended-release tablets
Disintegrate more slowly and have a longer duration of action.
Decreases the number of doses of tablets
Should NOT be crushed!

10. Oral Medications Sublingual tablets Coded tablets
Dissolve quickly under the tongue
Medication is absorbed through capillaries and reaches the circulation without passing through the GI tract.
Coded tablets
Have a number or letters, or both, that make them easily identifiable.

11. Oral Medications Syrups Elixirs Solutions
Solutions of sugar in water that disguise the medication’s unpleasant taste – contraindicated in patients with DM
Elixirs
Clear hydro-alcoholic liquids that are sweetened – contraindicated in patients with a history of alcoholism
Solutions
Clear liquids that contain a drug dissolved in water.

12. Oral Medications Powders
Dry, finely ground drugs that need to be reconstituted (dissolved) according to manufacturer’s instructions.
In liquid form, becomes an oral
suspension.
Oral antibiotics are often supplied in this form.

13. Dosage Calculations
In dosage calculations, you need 3 pieces of information:
The doctor’s or healthcare provider’s order
The quantity or strength of drug on hand
The solid or liquid form of the supply drug
Find a method that works for you
Three-step approach (formula method)
Ratio/Proportion
Expressed as ratios or fractions

14. Three-Step Approach Estimate before attempting to calculate dosage
Memorize approach
Use for every dosage calculation

15. Three-Step Approach D represents desired dosage or doctor’s order
H represents the dosage on hand per a quantity
Both H and Q represent the supply dosage found on the label of the drug available

16. Three Steps to Dosage Calculations Formula Method
Step 1. Convert
Ensure all measurements are in the same system of measurement and the same size unit of measurement.
If not, convert before proceeding.
Step 2. Think
Estimate what is a reasonable amount of the drug to be administered.

17. Three Steps to Dosage Calculations Formula Method
Step 3. Calculate Apply the formula

18. Ratio: Proportion
What you have : What you need Dosage on hand = Dosage desired Amount on hand X amount desired Supply = Dosage Have X amount

19. Three Step Approach Doctor’s order: Aricept 10 mg po daily
Convert
No conversion is necessary. Units are in same system (metric) and the same size (mg).
Think
Wanting to give 10 mg and you have 5 mg in each tablet. You want to give twice the equivalent of each tablet or 2 tablets per dose.

20. Doctor’s order: Aricept 10 mg po daily
Ratio/Proportion:
Step 3-Calculate:

21. Doctor’s order: Verapamil SR 240 mg po daily
Convert – none needed
Think – What I need is what I have
Calculate – no calculation needed

22. Ordered: Flagyl 0.75 g po tid How many tablets per dose should be administered?
Convert
Think
Calculate

23. Ordered: Flagyl 0.75 g po tid How many tablets per dose should be administered?
Convert: g to mg = 750 mg
Think: Am I going to give more or less
than I have on hand?
Calculate:

24. Oral Liquids
Oral liquids are supplied in solution form and contain a specific amount of drug in a given amount of solution.
The supply container label indicates the amount of drug per 1 milliliter or per multiple milliliters of solution.
10 mg per 2 mL
125 mg per 5 mL
1.2 g per 30 mL

25. Doctor’s Order: Ceclor 250 mg po q 8h
Convert
Think
Calculate

26. Doctor’s Order: Ceclor 250 mg po q 8h
Convert: No Conversion necessary
Think: I need to give 2 times the amount
I have on hand
Calculate:

27. Order: Potassium 40 mEq po daily
Convert: No conversion is necessary
Think: you want to give more
than 20 mEq, actually twice
as much.
Calculate:

28. Conversions If the dosage is not in the same size unit of measurement
You must convert to the same system or same size units
Metric to metric is most often used
Usually go to smaller unit
Household Measurements
Convert to metric equivalents
Metric system is predominant system of measurement for drugs

29. Converting to Same System
Math Tip
In most cases, it is more practical to convert to smaller unit
Usually eliminates decimal or fraction, keeping calculation in whole numbers

30. Math Tip
When solving dosage problems for drugs supplied in tablets or capsules
Q (quantity) is always one, because the supply dosage is per one tablet or capsule
Q = One tablet or capsule

31. Remember Do not always rely on a formula.
Always estimate what is a reasonable amount of the drug to be administered.
This helps to identify if the dosages calculated are reasonable and sound.

32. Problem
The physician ordered Amoxil (amoxicillin) 0.5 g p.o. q 8 h. Available is Amoxil (amoxicillin) oral suspension 250 mg/5mL, total volume of bottle is 180 mL.
a. How many mL of Amoxil will you administer? __________ or __________ t
b. How many full doses are available? ______
c. If the physician’s order is for 5 days, is this an adequate total volume? __________
10 mL 2 18

33. Problem
The physician ordered Prozac (fluoxetine hydrochloride) 40 mg p.o. at 0730 and Available is Prozac oral solution of 20 mg/5mL.
a. How many mL of Prozac will you administer? _______________
b. If the bottle contains 120 mL, how many days will this last? _________________
10 mL
6 days

34. Problem
The order states Zithromax oral suspension 600 mg p.o. 1 hr ac in am. Available is Zithromax 200 mg/5 mL.
a. If breakfast is served at 0800, when should the nurse administer the medication? ______
b. How many mL will you administer? ___
____ or ________ t________ T
0700
15 mL 3 1

35. Problem
The order reads K-Lor (potassium chloride) oral solution 60 mEq in equally divided doses p.o. tid pc (30 min – 1 hr) a. How many mEq should you administer per dose? ___ b. If K-Lor solution is available 20 mEq/15 mL, how many mL will you administer daily? c. What times would you schedule the medication if breakfast is 0800, lunch is 1200, and dinner is 1700?
20 mEq
, ,