Please remember this is about 1/3 of the pharmacology exam. It may be beneficial for you to practice calculations and/or review a nursing math book to help prep. You may not have used all the calculation methods recently. Questions may include one or more type of calculation. Tips:
1. READ CAREFULLY. Always be sure you know what the end result should be (mg, pills, ml, etc.). This can help you select the correct formula and eliminate unnecessary information. 2. Double (and triple) check actual math. Did you clear the calculator correctly? 3. Does the answer make sense?
4. There are both adult and pediatric calculations.
5. Watch ‘per dose’, ‘per day’.
6. How you calculate the answer does not matter (desired over have, ratio : proportion, etc.); accuracy does.2Common calculations include (but are not limited to): 1. Kg to mg to mcg conversion (any which way)
L
K H D M D C M – – mcg
G
liter
(kilo – hecto – deca – meter – deci – centi – milli – skip – skip – micro) gram
2. Dosage calculations
a. Tablets
b. mg. to tablets
c. mg. to ml
d. units to ml
e. kg to ml
f. Half-life calculation
g. IV rate calculation (hourly infusion rate) AND adjustment h. IV rate dosage calculation (based on units per ml, etc.)
i. Macro- vs. micro-drop tubing
j. Calculating drops/minute (gtts/min)
Examples: (abbreviated to type of question; exam will add extra information)
1. Have 5 mg tablets; ordered dose 2.5 mg. How many tablets will the nurse administer? 2. Have 2 mg/2 ml; order is 1 mg. How many milliliters will the nurse administer? 3. Prepare a 20 mEq dose of a medication.
Available solution is 40 mEq/10 ml. How many ml will be administered? Note: calculation method is not different in examples 1 – 3, just the unit of measure (mg, units, mEq, etc.). BE SURE AVAILABLE AND HAVE ARE THE SAME UNIT OF MEASURE. 4. Half-life conversion: Half-life is known to be 2 hours. What percentage will be left in the body after six hours? 5. A person weighs 165 lbs. How many kg does the person weigh?6. The available medication has been reconstituted to 250 mg/5 ml.
The order is 5 mg/kg/daily in two evenly divided doses. Child weight 44 pounds. How many milliliters will be administered per dose? NOTE: More than one calculation method must be used to answer this question. 7. IV was ordered at 1000 ml over 8 hour period. After two hours, only 900 ml has infused. Calculate the new infusion rate for the medication to be administered within the original 8 hour period. 8. Order is for 3000 cc over a 24-hour period. What is the hourly flow rate? OR:
What will the pump be set at per hour? 9. Order is for antibiotic to be mixed in 50 ml NS and administered over 45 minutes. What is the hourly flow rate? OR: What will the pump be set at per hour? 10. Volume is 1000 ml. Ordered infusion time is 8 hours.
Have tubing of 15 drops/ml. How many drops need to be counted to deliver the identified milliliters per minute? 11. Available solution = 25,000 units in 250 ml NS. Order is to administer at 22 ml/hour. How many units will be given per hour? 12. Available solution = 25,000 units in 250 ml NS. Administer at 2000 units/hour. How many ml will be given be hour? OR: What will the pump be set at per hour? Principles of Pharmacology.
These include the basics! Review:
1. Routes of administration – benefits and problems
2. Sizes of needles and syringes for injections
3. Six Rights of Medication Administration; Three Checks
4. Side effects; adverse effects; paradoxical reactions; toxicity; antagonists 5. Half-life calculation
6. Allergic or hypersensitivity reactions
7. Absorption, metabolism, distribution and excretion
8. There may be questions on lab values as relevant.
9. There are pediatric and adult questions.
10. Immunosuppression precautions (due to meds for cancer, HIV/AIDS, etc.).