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HEAL-105 — Learning Activity Module Lesson 2 One-step conversions between systems

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HEAL-105 — Learning Activity Module Lesson 2 One-step conversions between systems.   You may want to print out this module overview and read it before proceeding with the learning activities.  Print the activity pages, complete your work on them, scan your work and submit electronically. Module Summary The approximate amount of time required to complete this module is 1 hour. Learning Goals After completing this module, you will be able to     1)   Use a calculator to solve problems involving fractions and get an appropriate fractional answer     2)   To do a one step conversion using dimensional analysis that converts units between two different systems of measurement. Learning Activities To complete this module successfully, you must complete the following learning activities. There are two parts to this assignment (How to read a medication label and Converting between systems). There are practice problems for both. However, you are not submitting the practice problems for part 1. You are submitting the practice problems and graded assignments for part 2.   Read all of Lesson 2 (How to read medication labels and Converting between systems) Complete the Examples and Practice Problems for Converting Between Systems and check your answers. Complete the graded section of Assignment #2 and submit both online   Updated: 28-Oct-22                                        Howard Community College

 

 

Lesson 2 Part 1: How to read a medication label

 

 

Image: This is a medication box for Atropine.

 

Medication packaging has a wealth of information. It is important to read the packaging carefully however as sometimes a piece of information is expressed several ways and if you are not reading this carefully you can make mistakes. There are some consistent features provided on labels, but there is not an industry standard except for stating the drug name, dose, lot number and expiration date which is required.

Typical Information on each label

• Drug names
  • Trade name/Brand Name (same thing) - The brand name is then name the manufacturer uses for their version of the drug. The standards of purity and consistency, etc. apply for their formulation, but this is where the company gets to use its own name. Often these names are so well known that they become a surrogate for the generic name. An example of this is Tylenol, which is a trade name for acetaminophen (generic name).
  • Generic name – This is often not alphabetized on the label, but it can be. Often inside parentheses. Often you find the letters USP or NF after the drug name. These indicate where the information on the drug is officially listed in pharmaceutical references and includes the United States Pharmacopeia and the National Formulary.
• Dosage
  • This can be written several ways so read this carefully!
    • Dosage may be listed per unit (tablet, capsule, etc.)
    • Is this packaging meant for a single or multiple doses? (this one states single dose- can you find it on the label?)
    • Dosage per entire container  (atropine 1 mg/10mL- can you find that?)
    • Final concentration dosage (atropine 0.1 mg/1mL- can you find that?)
• Form the medication is in in this container
  • Just because it is a liquid that does not mean it can be injected. It should say “for injection” or something similar on the packaging. The atropine label has “Inj” between the generic name and USP identification. Also, this is packaged in a prefilled syringe so there is that big clue as well!
• Manufacturer Information
  • Expiration date. ALWAYS CHECK THIS DATE. We will talk more on expiration date.
  • Lot number. This is generally recorded by the pharmacy when dispensed for tracking purposes. This is not generally logged when used by the end-users outside of the pharmacy (nurse, paramedic, tech, etc.) but in some cases, such as with a double blind experiment, it may be logged when used as well.
  • Special precautions (if any). These may include storage concerns, temperature for storage, need to keep out of direct sunlight, etc.
    • Temperatures may include needing refrigeration (some insulin preps for example)
  • Special handling instructions (if any). For example: Wear gloves and respiratory protection when handling, etc. You see this with drugs such as chemotherapy agents, nitrates, or some hormone medications. You also frequently see precautions on getting things into the eyes or splashing or absorbing it through the skin.

Medication Expiration Date

Every drug should have an expiration date listed on it somewhere but there is more to this than a date.

• The expiration date is set well in advance of the actual date the medication expires. There is a formula used in the manufacturing business that takes into account how stable the med is in different temperatures and forms (solid, liquid, etc.) and determines the optimal date to set for expiration. In first world nations such as ours you find medications are often set to expire with a large window for safety. Often these “expired” medications are collected and shipped to 3^rd world countries for immediate use because they are still safe to use and administer. These medications are tested before being distributed and there are precautions taken to ensure that they are still safe to use. When there are shortages of medication in the US you may see “expired” medications remaining in circulation for a while after their expiration date. This process and any policies pertaining to this practice should be driven by pharmacists.
• Storage methods include focusing on lighting conditions, optimal temperature ranges (not too hot, too cold, or freezing) and if the medication is being agitated frequently (such as if being carried on an ambulance that is driving around). All of these things can affect the medication in subtle, or not so subtle ways which can result in shortened expiration dates or altered efficacy. There are now standards applied to storage concerns on ambulances which were not addressed until the last 20 or so years.
• When a medication truly expires it may lose potency, gains potency or changes to a different drug altogether. For example, aspirin will take on a strong order of vinegar when it degrades due to chemical changes within the medication and it should no longer be used when you detect this odor whether or not the expiration date has been reached.
• For medications with just a month and year for the expiration date the convention in the pharmacy world is to use it until the last day of that month. For example: your aspirin bottle says “use by 12/2020” so that means you should use it or discard it by December 31, 2020.
• For medications which require reconstitution prior to use, there will be information stating the use by date as well as the date to set once you reconstitute it. For example, many of the oral antibiotics such as the penicillin family of meds will state to throw it out 14 days after reconstituting and also to store it in the refrigerator.

A word about discarding medications

Your clinical practice area should have a policy on how to discard medications. Pharmacies often will take back medications for disposal as well. It is not a good idea to flush medications or run them down the sink as this can introduce contaminants into the environment.

 

 

 

 

Practice Problems (ungraded)

 

The answers are provided after the questions. Cover up the answers and answer the questions without peeking! No need to submit these practice problems.

 

1. Study this label and answer the 3 questions below:

 

1.            What is the generic name?

2.            What form does this medication come in?

3.            Why does it list 10mg/400mg? What does this mean?

Answers:

1. What is the generic name? This is a combination medication containing hydrocodone bitartrate and acetaminophen. These are the generic names of the medications found in the tablet.
2. What form does this medication come in? This is a tablet. This label shows a picture of the tablet which is helpful. You would use the shape, color, and any information stamped into the pill to identify it using some of the commercial medication guides if you have a pill with no label or prescription bottle.
3. Why does it list 10mg/400mg? What does this mean? This medication is a combination of 2 medications. If you read the right side of the label it tells you which is which dose, but you could also infer that by the order it is written in.

NOTE: Do you see the large C with the III (Roman numeral 3) inside it on the label? This is the official image for controlled medications on the “schedule” for narcotics and drugs capable of addiction or being abused. Drugs are placed on schedule I through V based upon class, family they belong to, and addictive capabilities. Schedule I are generally only used in research and have the tightest level of control. All the rest can be distributed but because they are “controlled substances” and there will be strict regulations requiring handing, distributing and prescribing of these medications. Your supervisor or employer will have additional information you are following in your clinical practice with these medications.

NOTE: The image R_x appears on some medication packaging labels and boxes as well. All it means is that this medication is available only by prescription. An absence of this image does not indicate it can be gotten without a prescription, or over the counter.

 

2. Study this label and answer questions 4-8.

 

4.            What is the trade name?

5.            Is the final concentration listed on this label?

6.            How would you determine final concentration for this medication?

7.            What special information/precautions do you see on this label?

8.            Can this liquid be injected?

Answers:

4. What is the trade name? Augmentin
5. Is the final concentration listed on this label? No it is not. A concentration of 125 mg / 5 mL is listed on the label, but remember, final concentration inform you of the weight (amount) of medication that is found in 1 mL of fluid.
6. How would you determine final concentration for this medication? You would have to calculate this. If you divide 125 (mg) by 5 (ml) you get the answer: 25 mg/1 ml
7. What special information/precautions do you see on this label? Instructions on reconstituting which breaks it into a couple steps, it tells you to break up the powder before reconstituting, the amount of water to use to reconstitute (67 ml), the need for refrigeration once mixed, and instructions to discard after 10 days of being reconstituted. It also refers you to the package insert (which likely has more information for you to give to the family).
8. Can this liquid be injected? No it cannot. It specifically says oral suspension. Also, because it is an oral suspension it will need to be shaken before measuring out each dose.

 

3. Look carefully at these two labels. Note that these vials contain the same medication. They look almost the same size but one contains less volume than the other despite the packaging similarities. Answer questions 9-13.

9. What schedule is this medication?

 

10. What is the amount of medication in each vial?

 

11. What is the final concentration for each vial?

 

12. What precautions do you see?

 

13. Is the name of this drug a generic or trade name? How do you know?

 

Answers:

9. What schedule is this medication? Schedule III (3). You can see the label clearly on the vial to the right.

10. What is the amount of medication in each vial? Each vial contains a total of 500 mg of medication. The upper left hand corner of each label shows you how many total mL are in each vial. Left has 10 mL and right has 5 mL. Not also that both vials are labeled as multi-dose vials so they can be used for multiple times, and in some settings they will be used for more than 1 patient.

11. What is the final concentration for each vial? The Left vial final concentration is 50 mg / mL and the right vial has 100 mg / mL.

12. What precautions do you see? Both vials have the schedule listed, and messages on the route the drug can be used (IM, IV, etc.) as well as the precaution to inject the medication slowly. The vial on the right also states it must be diluted prior to giving it IV.

13. Is the name of this drug a generic or trade name? How do you know? The drug name is generic. You can tell because of the ,USP after the name.

 

 

Lesson 2 Part 2: Converting between systems

1. Converting other systems are done the same way as converting within the metric system.

Example: 

1. Start by writing the fraction in traditional form with the units in the numerator.  
2. Multiply by the needed conversion.   

3. Cancel matching units
4. Complete calculations.   [Ans. 4 floz]

 

II.   Converting between the Systems (one-step only)   

Go over the total conversion sheet.  Reminder: You will need to memorize these conversions for the tests.    Many students find they do this just by doing the homework; others need techniques like writing note cards and reciting the conversions aloud.

Chapter 5 in the text provides examples on converting between the systems.  The textbook has many more conversions in their tables then we do.  You only need to memorize the conversions in your information packet.  Pay particular attention to the measuring cups in figure 5.1 on page 118.  This is a great aide for visualizing comparable amounts.   Being able to convert between the systems is very important. 

       Essential steps

1. Start with the order or initial piece of information.   
2. Write the information in terms of a fraction such as
3. Now, check for the expectant or end unit you will need to end up with.
4. Figure out what conversion is the best.
5. Multiply by the conversion fraction so that the original units cancel out and you have the answer units in the numerator.        

 

 

More Examples:

Example #1.        120 gr = ______ g

Students frequently confuse grains (gr) from the apothecary system with grams (g or G) from the metric system.  What is the conversion factor for grains and grams?   Write the fraction so that grains will cancel out.

  complete the division ;  120 / 15 =  8 g

  

Example #2.        200 gr = _____ mg

 What is the conversion factor for grains to milligrams? 

Write the fraction so that gr will cancel out, then complete the arithmetic.

                                              (Answer: 1200 mg)    

 

Example #3.       The doctor ordered gr  _1/600    of atropine sulphate for a patient.    What is the equivalent in milligrams?

    Start with the order;  then put in the appropriate conversion:    

     

Notice again that the <<grain>> units cancel out and leave only mg.    (Answer:  0.10 or 0.1 mg)

Reminder:  Metric units should be left in decimal form; non-metric units are left in fractional form.

 

Which conversion should you use?  If the problem begins with grams, use the grain to grams conversion.  If the problem includes milligrams and grains, then use that conversion.  Remember that both conversions are approximations so you may not get the same answer if you introduce additional steps.  

   Practice Problems for Lesson 2 (ungraded)

When converting "between" the systems use the conversion sheet.  You will need to memorize these conversions before the test.  Solutions are at the bottom of this page. Remember to follow the rules on notation found at the end of chapter 4 in the summary. 

 

1.      15 mL =______ t                              2.           3 fl oz      =  ______ mL

 

 

 

 

 

3.      120 gr    =  ______g                                       4.           200 gr =  ________mg      

 

 

 

 

 

 

5. The doctor ordered gr ¹/₆₀₀ of atropine sulphate for a patient.  What is the equivalent in mg?

 

 

 

 

 

 

 

 

 

 

Solutions to Practice Problems:

   1.     3t               2.  90 mL              3.   8 g                  4.     12,000 mg                  5.  0.1 mg

 

Print and submit the assignment pages.  Include detailed work.

 

HEAL 105  DRUG CALCULATIONS

Assignment 2 (graded)                                                                                        Student Name:

ONE-STEP CONVERSIONS

Show the set-up for each problem.

 

1.           5 T = ________t                                            2.           80 mL  = ________L

 

 

 

 

 

3.           16 gr  = ________mg                                                    4.           ¾ fl oz.   = ________T

 

 

5.           4  t  =  ________mL                                                      6.           2 qt  = pt ________

 

 

7.           2 t = ________ T                                            8.           gr ⁵/₈  = ________ mg

  

 

9.           5 mg = gr ________                                                      10.         gr ¹/₈ = ________ g

 

 

 

________11.        The order reads 0.5 g of chloramphenicol.  What is the equivalent in mg?

 

 

________12.        The order reads 80 mg of Inderal.  How many grams would you administer?

 

 

________13.   How many milliliters are contained in 3 tablespoons of a drug?

 

 

Assign #2        cont.                                                                Student Name:

 

 

________14.        The physician ordered 8 fl oz. of citrate of magnesia.  How many tablespoons would you administer?

 

 

 

________15.        The order reads 30 mL of a solution.  How many teaspoons is this?

 

 

 

________16.        The order is ¼ pint of fluid.  How many ounces are contained in this order?

 

 

 

________17.        The doctor ordered gr 4 of a drug.  Change this order to grams.

 

 

                 

________18.        Change 500 mg to grains.