Introduction

Using the oral route for medication administration is the safest and most frequently used means of administering medicines. Oral medications come in solid forms (such as tablets and capsules) and liquid forms. Variations of these solid forms, such as powders and granules, are dissolved in liquids for administration (see Chapters 8 and 9). Other advantages of administering medications orally include convenience for the patient, absence of damage to skin, and reduced cost of manufacturing the medication because the drug does not require the use of sterile technique, allowing the drug to be more economical.

Oral medications are absorbed in the gastrointestinal tract, primarily in the small intestine. Because of the differences in absorption rates due to age, gastric motility, gastric contents, and illnesses, the amount of medication that each patient receives may not be the same amount as the usually prescribed dose, therefore, a prescription or medical order is written to accommodate individual differences. These differences must be considered by the physician and are further checked and verified by the pharmacy professional as a means of checks and balances. Therefore, drug manufacturers often provide drugs in different strengths to meet the needs of each patient and to allow dispensing of the therapeutic dose necessary for each person. When the dose ordered is available in the needed dosage strength and form, fewer errors will occur with administration of the medication. The pharmacy technician must be aware of the various strengths of medications and take care in choosing the correct drug strength when preparing medications for dispensing.

Some medications may be irritating to the intestinal tract and may require eating a meal or snack to aid in absorption or to prevent irritation in the stomach. Others must have special instructions for taking the medicine, such as iron elixir, which can stain teeth and should be administered through a straw, or Fosamax, which requires the person receiving the drug remain in an upright position for at least 30 minutes after administration. Some tablets may be divided or crushed for ease in swallowing; the ability to divide the tablets is usually indicated by the tablet being scored. Remember, capsules should not be crushed or divided, although some may be opened and sprinkled on food for ease of administration after obtaining special permission from the physician.

Because solid oral medications are dispensed according to specific instructions for safety and for providing the correct doses, the pharmacy technician must be aware that calculation of exact dosages is an important factor in administering medications. Many drug dosages will be in the exact amounts that are found on medication labels, whereas others must be calculated to be sure the correct amount of medication is provided for administration. This chapter is designed to ensure that you can calculate doses and dosages from prescriptions and medication orders, using physician’s orders and drug labels.

Calculating Solid Oral Medication Doses

To provide the necessary medication for the administration of a solid oral dose, the label must be read carefully and the correct medication must be used in dispensing the drug. After choosing the appropriate medication, the pharmacy technician must be sure to calculate the amount of medicine to be given to the patient both in the individual dose and the entire amount of medication, or dosage. Care is necessary to supply the treatment prescribed for patient safety. The calculation of a dose depends on the amount of medicine that has been ordered at a given time, whereas dosage indicates the total amount of medicine that is necessary for the complete order or prescription. This chapter covers calculating both doses and dosages. Just as a reminder, the label on the medication provided and the prescribed medication must be either in the same measurement system or a form that can be converted to provide the prescribed medicine dose and dosage. Another important rule of thumb is that when converting among measurement systems, be sure the final conversion is in the same measurement system as that found on the label of the medication. In other words, if you are converting between milligrams and grams and the label on the medication is in grams per tablet, the final answer should be in grams per tablet or the number of tablets. Finally, be sure that the medication names are exactly the same, because many medications have sound-alike or look-alike names that are similar. If there is ever a doubt about the medicine to be used or if the calculation does not seem to be what you expected it to be, obtain clarification from the pharmacist before preparing the medicine, a practice that is always safe, important, and acceptable. The pharmacist—the person ultimately responsible for dispensing the medication—would prefer to answer questions before medication preparation rather than make a medication error by dispensing incorrect doses or medications.

More rules that should be considered when calculating medication dosage follow:

Drug calculations may be obtained by using one of three methods. The method that you feel the most comfortable using is the correct method for you to use. One method is using ratio and proportion (discussed in Chapter 2). Dimensional analysis is an extended form of ratio and proportion and may also be used for calculating a dose of medication. Finally, the following formula may be used for calculations:

< ?xml:namespace prefix = "mml" />DD(Dose desired)DH(Dose on hand)×Qty(Quantity or form)=Dose to be given(DG)

In the next section, each problem will be calculated using each of the three methods. Again, find the method with which you feel the most comfortable and use it for all your calculations. Always using the same methodology for calculations will assist in avoiding possible confusion during calculations.

Calculating Medications Using Ratio and Proportion

When using the proportional method of calculating doses, the dosage strength available (DA) and the dosage form (DF) must be one ratio, and the dose ordered (DO) and the dose to be given (DG) must be the second ratio in the proportion. Remember that in using a mathematical equation for ratio and proportion, the ratio shows the relationship between two numbers, and proportion shows the relationship between two ratios. When setting up a problem for calculation by ratio and proportion, the formula then appears as follows:

DA(Dosage available):DF(Dosage form)::DO(Dose ordered):DG(Dose to be given)

Remember that these relationships may also be written as fractional units if this is easier for your calculations. A fractional formula is as follows:

DADF=DODG

Tech Note

Note that the known dosage and the dosage form are on the left side of the proportion.

Also remember that when part of the ratio is missing, the unknown number is represented by “x”. If a calculation is necessary and one of the components of the proportion is missing, the missing part or x can be found by filling in the known parts of the proportion and then completing the problem as with any proportional problem. To use proportion, the dosage available (DA) and the dose ordered (DO) must be in the same measurement system. If the systems differ, conversion must be done to bring these components into the same system. (See Chapter 4 for help in remembering the measurement systems and Chapter 5 for help in converting among systems.) Later in this chapter you will calculate problems requiring conversion. Now you can begin performing calculations with medications in the same system.

Example 7-1

An order is written for 500 mg of medication, and the available medication strength is 250 mg/capsule.

In this proportion, if you know that 250 mg (DA) of a medication is found in 1 capsule (DF) and the order reads for the patient to be given 500 mg (DO), the ratio would look like this:

250mg(DA):1cap(DF)::500mg(DO):x(DG)

OR

250mg(DA)1cap(DF)=500mg(DO)x(DG)

Tech Note

DA and DO in this example are both in milligrams in the metric system so conversion to the same weight is not necessary.

Now multiply the means versus extremes or cross-multiply if in fractional components.

Drop the “mg” because this appears in both parts of the equation, and the equation now looks like this:

250x=500×1cap

x=500cap250

x = 2 cap, or the prescribed amount of medication to be given is 2 capsules

Tech Note

Remember that the dosage available and the dose ordered must be in the same measurement system or a conversion between measurement systems must be made so that the calculation is completed in the same measurements. The conversion should be to the dosage shown on the medication label.

Let’s try another medication order as an example, but this time we will use measurements in the apothecary system.

Example 7-2

A medication order is written for gr (DO) to be given, and dose available is gr (DA) in each tablet (DF). What is the dose to be given to the patient?

gr14(DA):1tab(DF)::gr34(DO):x(DG)

OR

gr1/4(DA)1tab(DF)=gr3/4(DO)x(DG)

As previously, drop the “gr” because this appears on both sides of the equation. Again, either multiply means and extremes or cross-multiply the fractional components. The resultant formula is as follows:

14x=34×1

x=34×41

x=31or3tablets

Tech Note

Remember that when a fraction crosses the = sign, it is inverted.

Calculating Medications Using Dimensional Analysis

Dimensional analysis is actually just an elongated form of ratio and proportion using multiple fractional units. To use dimensional analysis, ratios must allow for the cancellation of measurements from one ratio into the next. (See Chapter 5 for a review of dimensional analysis basics.)

Tech Note

Remember to place the known as the first fraction in the proportional equation. This will help you make the needed conversions to the desired answer.

Tech Note

Using dimensional analysis is especially helpful when conversions between measurement systems are necessary to arrive at the answer.

If the previous problems were calculated in dimensional analysis, the first problem would read as follows:

Example 7-3

An order is written for 500 mg of medication, and the available strength is 250 mg/capsule.

xcaps=1cap250mg×500mg1

xcaps=1×21×1orxcaps=21

xcaps=2capsules

Example 7-4

A medication order is written for gr (DO) to be given, and the dose available is gr (DA) in each tablet (DF). What is the dose to be given (DG) to the patient?

xtabs=1tabgr1/4=gr3/41

Dose to be given will be3tablets.

Calculating Medications Using the Formula Method

Many professionals use the formula method to calculate doses. Using the formula, replace each component of the formula with the correct information and then calculate the problem. This is the same means of replacement as is used with ratio and proportion, but the formula is used for placing the given amounts. The formula follows:

DD(Dose desired)DH(Dose on hand[DA])×Qty(Quantity[DF])=Dose to be given(DG)

Quantity in solid medications will appear as capsules or tablets, whereas in liquid form the quantity may be found in the number of mg, g, or other weight measurement in the volume of medication, or may be given mL, drops, or other liquid volume measurements.

Example 7-5

An order is written for 500 mg of medication, and the available strength is a 250 mg capsule.

500mg(DD)250mg(DA)×1cap(Qty[DF])=Dose to be given(DG)

Tech Note

Because “mg” is found in both the numerator and denominator, it may be canceled. Also notice the dosage form (a capsule in this example) has remained in place as the quantity in this formula.

500250×1cap=DG

500÷250=2

2×1=2capsules to be given

Example 7-6

A medication order is written for gr (DO) to be given and the dose on hand is gr (DH or DA) in each tablet (Qty or DF). What is the dose to be given (DG) to the patient?

gr3/4gr1/4×1tab=Dose to be given(DG)

Again, remember that “=” has been crossed and the fraction has been inverted

Dose to be given=3tabs

Please notice that both of these problems are done within the same measurement system. After the practice problems, you will begin working between measurement systems for calculating doses and dosages.

Practice Problems A

Calculate the practice problems below. Show all your calculations. Remember to use the method of conversion that is most comfortable for you. Indicate how the medication order would be shown on a prescription label.

Tech Note

Medications in tablets, capsules, syrups, elixirs, suspensions, and the like may or may not have “po” within the medication order or prescription; however it is assumed professionally that these forms of medications are to be taken by mouth.

NOTE: This chapter concerns oral medications so when interpreting orders for labels be sure to include that the medications are to be taken by mouth.

1. Order: Synthroid 175 mcg po daily in am

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

2. Order: ferrous sulfate gr po qam

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

3. Order: ciprofloxacin 1.5 gm po qam

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

4. Order: digoxin cap 0.1 mg po qam P ↑ 60 until changed by MD

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

5. Order: Lopid 1.2 gm qam am meal

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

6. Order: Dilantin 0.5 gm bid breakfast and evening meal

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

7. Order: metformin HCl 1 gm po bid meals. Ck BS before taking medication

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

8. Order: Biaxin 500 mg po bid food

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

9. Order: pravastatin 20 mg po daily hs*

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

10. Order: Ativan 0.5 mg po q6-8h or hs prn anxiety*

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

11. Order: Retrovir 200 mg po qhs*

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

12. Order: ASA gr x × po q4-6h prn aching; do not exceed 8 tab q24h

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

13. Order: cephalexin 0.75 gm po bid breakfast and hs

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

14. Order: Decadron 0.75 mg daily @ same time

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

15.  Order: promethazine 0.0375 gm q4-6h prn N&V

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

16. Order: Lotrel 5/20 daily in am

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

17. Order: isoniazid 250 mg tid meals

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

18. Order: Evista 0.12 gm po daily

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

19. Order: Voltaren 0.05 gm bid meals

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

20. Order: carbamazepine 0.2 gm qid with meals and hs*

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ___________________________________________________________________

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^*These abbreviations are found on the TJC Do Not Use List and ISMP’s List of Error-Prone Abbreviations, Symbols, and Dose Designations due to medication safety issues. They should not be used. You are being tested on them here because these abbreviations may still appear in the pharmacy setting.

^*These abbreviations are found on the TJC Do Not Use List and ISMP’s List of Error-Prone Abbreviations, Symbols, and Dose Designations due to medication safety issues. They should not be used. You are being tested on them here because these abbreviations may still appear in the pharmacy setting.

^*These abbreviations are found on the TJC Do Not Use List and ISMP’s List of Error-Prone Abbreviations, Symbols, and Dose Designations due to medication safety issues. They should not be used. You are being tested on them here because these abbreviations may still appear in the pharmacy setting.

Calculating Solid Medications Among Different Measurement Systems

Remember from Chapter 5 that conversions among measurement systems are approximates, and amounts are often not exact but as close as possible with the medications ordered and medications available. To figure the dose to be given, you must first convert so that the medication ordered (DO) and the medication on hand (DA) are in the same measurement system. (Solid medications taken orally do not require the use of conversions to the household system, so this is covered in Chapter 8.)

Example 7-7

The physician orders ASA gr daily for a patient with coronary disease. The medication on hand is labeled ASA 81 mg tab.

First, the order as written by the physician must be interpreted, and then the calculation of the dose must be completed. In this order, the physician wants the patient to take aspirin (ASA) grains daily. Now you know that the dose will be grains of medication, but you do not know the number of tablets that are to be administered or (DG). The order is written in the apothecary system, whereas the medication available is in the metric system. So, you must now make a conversion for this order to be filled. Under the general rule to convert to the available medications, in this case the conversion should be from apothecary to metric. In Chapter 5 you learned that one grain is equal to 60 mg, or the conversion necessary for this order. Also remember that the known equivalency should be placed on the left of the ratio and proportion formula with the unknown on the right of the equation.

Known Unknown

gr i:60mg::grI¯˙I¯˙ss¯:x

x=60×212

x=60×52or60×52or3002

x=150mg

Following the conversion, the amount necessary is 150 mg of ASA, so now the formula, ratio and proportion, or dimensional analysis calculation may be used to figure the number of tablets necessary for the dose ordered.

Ratio and Proportion Method

81mg(DA):1tab(DF)::150mg(DO):x(Dose to be given)

81x=150×1tab(150)

x=150÷81

x=1.85,rounded to1.9or2tablets(then round to the nearest whole number)

Dose to be given=2tablets.

Dimensional Analysis Method

Dimensional analysis will allow you to make the entire conversion in one proportional equation. Using dimensional analysis, the step of changing from apothecary to metric may be done as part of the equation in the following:

xtabs=(212×60×1)÷(1×1×81)or150÷81

xtablets=1.85round to1.9or2tabs

Tech Note

Remember that when converting, the answer may be approximate rather than exact. The exact answer is 1.85 or 1.9, which will be rounded to 2 tablets.

If you prefer, you can make your conversion from apothecary to metric before figuring the dose. Then calculate the dose by dimensional analysis as follows:

xtabs=1tab81mg×150mg1

xtabs=150÷81

xtabs=1.85round to1.9or2tablets(see Tech Note above)

Formula Method

150mg(DD)81mg(DA)×1tabs(DF)=Dose to be given(DG)

(150÷81)×1=Dose to be given(DG)

Dose to be given=1.85round to1.9or2tablets(see Tech Note above.)

In some cases you must convert within a system such as micrograms to milligrams or milligrams to grams or vice versa. If so, make the conversion within the system before converting between systems.

Tech Note

All the methods of conversion between systems are included, choose the method that is most comfortable for you to use and use it consistently.

Practice Problems B

Calculate the following problems, using the method that is most comfortable for you. Show all calculations. Indicate how the medication order would appear on the prescription label.

1. A physician orders ferrous sulfate gr v po bid. The available medication is labeled ferrous sulfate 325 mg tabs.

Interpret the order. __________________________________________________________________

Dose to be given: ____________________ tablet(s)

Prescription label: ___________________________________________________________________

2. A physician orders phenobarbital grtab po hs.* The medication available is labeled phenobarbital 60 mg tabs.

Interpret the order. __________________________________________________________________

Dose to be given: ____________________ tablet(s)

Prescription label: ___________________________________________________________________

3. A physician orders codeine sulfate 60 mg q4-6h prn pain. The medication available is labeled codeine sulfate gr tab.

Interpret the order. __________________________________________________________________

Dose to be given: ____________________ tablet(s)

Prescription label: ___________________________________________________________________

4. A physician orders Nitrostat gr 1/150 SL q5min up to 3 doses prn angina. The medication available is labeled Nitrostat 0.4 mg tab.

Interpret the order. __________________________________________________________________

Dose to be given: ____________________ tablet(s)

Prescription label: ___________________________________________________________________

5. The physician orders aspirin gr x po q4-6h prn high fever or aching for a patient with influenza. The medication available is labeled aspirin-DS 650 mg tab.

Interpret the order. __________________________________________________________________

Dose to be given: ____________________ tablet(s)

Prescription label: ___________________________________________________________________

6. A physician orders ferrous sulfate 650 mg bid breakfast and evening meal. The medication available is labeled ferrous sulfate gr v tab.

Interpret the order. __________________________________________________________________

How many tablets will be given with each dose? ____________________

Prescription label: ___________________________________________________________________

7. A physician orders codeine sulfate grpo q4h prn pain or cough. The medication available is labeled codeine sulfate 15 mg tab.

Interpret the order. __________________________________________________________________

How many tablets will be given with each dose? ____________________

Prescription label: ___________________________________________________________________

8. A physician orders phenobarbital 30 mg po tid and hs* for epilepsy. The medication available is labeled gr tab.

Interpret the order. __________________________________________________________________

How many tablets will be given with each dose? ____________________

Prescription label: ___________________________________________________________________

9. A physician orders Nitrostat 0.6 mg SL q5min × 3 doses prn angina; call 911 if no relief. The medication available is labeled Nitrostat gr 1/100 tab.

Interpret the order. __________________________________________________________________

How many tablets will be given with each dose? ____________________

Prescription label: ___________________________________________________________________

10. A physician orders codeine sulfate 90 mg po q4-6h prn pain in left hip. The medication available is codeine sulfate gr 3/4 tab.

Interpret the order. __________________________________________________________________

How many tablets will be given with each dose? ____________________

Prescription label: ___________________________________________________________________

---

^*These abbreviations are found on the TJC Do Not Use List and ISMP’s List of Error-Prone Abbreviations, Symbols, and Dose Designations due to medication safety issues. They should not be used. You are being tested on them here because these abbreviations may still appear in the pharmacy setting.

^*These abbreviations are found on the TJC Do Not Use List and ISMP’s List of Error-Prone Abbreviations, Symbols, and Dose Designations due to medication safety issues. They should not be used. You are being tested on them here because these abbreviations may still appear in the pharmacy setting.

Calculate Total Dosages Of Medication From Physician’s Orders

Physicians may state an order for a medication to be given so many times a day over a desired length of time. To be able to complete this order in an inpatient setting, the order will be dispensed on a daily basis for the desired time. If this same prescription is provided in a retail environment, the pharmacy technician will be required to calculate the number of doses that will be necessary for dispensing the complete prescription to the patient. This will require the pharmacy technician to find the number of doses in a specific day and then multiply this by the days that the medication is necessary.

Patient Safety When Calculating Doses And Dosages

As a pharmacy technician, you must always be aware that patient safety and accurate calculations are a necessity when preparing medications for dispensing. Medication orders or prescriptions are the physician’s determination of the medication and the amount that should be safe for the patient. The triangulation among the physician, pharmacist, and pharmacy technician or other health care team member is necessary to ensure this safety. In the center of the triangle is the patient, who is dependent on health care professionals to provide medications that are as risk-free as possible.

To be certain that the medication is correct and in the correct dosage, you should follow certain safety rules.

Review

When calculating solid oral medication doses, the amount of medication should be calculated to that of the physician’s order. Remember that the DA and the DO must be in the same system before calculating doses. When the medication label contains an amount of medication within one measurement system and the order does not agree with the measurement within the system for the available amount, you calculate the amount of medication necessary for the order by making conversions within the system. However, if the medication order and the available medications are in different measurement systems, you must use conversions as found in Chapter 5 to be sure the medications are converted to the same system. (See Chapter 4 for the measurement in the metric, household, and apothecary systems.) If a conversion must be made, it should be made to the measurement system found on the medication label.

Medication doses can be calculated using ratio and proportion (using the equation below):

DA(Dosage available):DF(Dosage form)::DO(Dose ordered):DG(Dose to be given)

OR

Medication doses can also be calculated using dimensional analysis in which the available medication should begin the ratios found in the proportional equation with the necessary conversions following your initial entry.

OR

The formula method, using the formula shown below may be used:

DD(Dose desired)DH(Dose on hand)×Qty(Quantity or form)=Dose to be given

As a pharmacy technician, you should find the method that is most comfortable for you and use it for all calculations.

A physician may give an order that requires the calculation of the total amount of medication necessary for dispensing a medication. To make this calculation, find the number of doses necessary in a day and then multiply this total amount by the total number of days that the prescription is to be taken.

Posttest

Before taking the Posttest, retake the Pretest to check your understanding of the materials presented in this chapter.

For the following problems, pick the correct label from the set below and put the label letter in the space indicated. Then, using the label, interpret the order and calculate the ordered medications. On the fourth line, indicate how the order would look on the prescription label. Figure the dose to be given in the dose form (i.e., tabs or caps) and indicate the form in the answer. Months are 30 days unless otherwise stated. Show all calculations.

 1 Order: Tagamet 0.8 g bid

Correct label: ____________________

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ____________________

 2 Order: HydroDIURIL 100 mg qam pc am meal

Correct label: ____________________

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ____________________

 3 Order: Tylenol gr x q4-6h prn fever

Correct label: ____________________

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ____________________

 4 Order: ciprofloxacin HCl 0.5 g tid meals

Correct label: ____________________

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ____________________

 5 Order: cefaclor 0.75 g daily in 3 divided doses

Correct label: ____________________

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ____________________

 6 Order: diltiazem-SR 120 mg po stat then 60 mg po daily

Correct label: ____________________

Interpret the order. __________________________________________________________________

Total number of tablets needed for a 30-day supply: ____________________

Dose to be given stat: ____________________

Dose to be given daily: ____________________

Prescription label: ____________________

 7 Order: rifampin 300 mg po daily in 2 divided doses

Correct label: ____________________

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Dosage for a month’s supply in September: ____________________

Prescription label: ____________________

 8 Order: Lopressor 100 mg po bid today and then 50 mg po bid × 15 days then 50 mg po qam for the remainder of December. (Today is December 1.)

Correct label: ____________________

Interpret the order. __________________________________________________________________

Total dosage to be given today: ____________________

How many capsules are in each dose today? ____________________

Total daily dosage to be given starting tomorrow: ____________________

Number of capsules for each dose starting tomorrow: ____________________

Total capsules that should be dispensed to fill the order: ____________________

Prescription label: ____________________

Using the following labels, interpret the order and calculate the ordered medications. Figure the dose to be given in the dose form (i.e., tabs or caps) and indicate the form in the answer. Months are 30 days unless otherwise stated. Show your calculations.

 9 Order: tetracycline 500 mg qid × 5 d; then 500 mg bid × 5 d; then 500 mg daily × 5 d for acne

Interpret the order. __________________________________________________________________

Dose to be given with each administration: ____________________

Total number of capsules that will be given in the first 5 days: ____________________

Total number of capsules in days 6-10: ____________________

Total number of capsules necessary to fill the prescription: ____________________

What is the total dosage per day in the first 5 days? ____________________

What is the total dosage per day for days 6-10? ____________________

What is the total dosage per day for the last 5 days? ____________________

Prescription label: ____________________

 10 Order: codeine phosphate grpo stat and q4-6h prn pain

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ____________________

 11 Order: nitroglycerin gr 1/150 subl q5min × 3 doses as a maximum dose for chest pain or until ↓ pain

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ____________________

 12 Order: Urecholine 20 mg po bid meals × 10 d

Interpret the order. __________________________________________________________________

Choose the correct container of medication. ____________________

Dose to be given: ____________________

Dosage to be dispensed for the order: ____________________

Prescription label: ____________________

 13 Order: Benadryl 50 mg po tid prn itching

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ____________________

 14 Order: Cipro 0.75 g po bid × 10 days

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Dosage to be dispensed to fill the prescription: ____________________

Prescription label: ____________________

 15 Order: ampicillin 1 gm po stat, then 500 mg po qid × 12 d

Interpret the order. __________________________________________________________________

Dose to be given stat: ____________________

Dose to be given qid: ____________________

Dosage necessary to correctly dispense the medication: ____________________

Prescription label: ____________________

 16 Order: temazepam 0.015 g po hs* prn sleep

Interpret the order. __________________________________________________________________

Dose to be given prn: ____________________

Prescription label: ____________________

 17 Order: Strattera 0.05 g po daily breakfast

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

How many capsules should be included in the entire prescription for a month? ____________________

Prescription label: ____________________

Dosage of medication to be supplied for a 45-day supply: ____________________

 18 Order: Surfak i or ii cap po qhs* prn

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Total number of mg taken when ii cap are taken hs: ____________________

Prescription label: ____________________

 19 Order: Synthroid 0.1 mg qam

Interpret the order. __________________________________________________________________

Dose to be given: ____________________

Prescription label: ____________________

 20 Order: Aldomet 0.25 g po qam and 0.125 g po @ 5 pm

Interpret the order. __________________________________________________________________

Dose to be given in tablets in am: ____________________

Dose to be given in tablets @ 5 pm: ____________________

Total dosage to be dispensed for 30 days: ____________________

Prescription label: ____________________

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^*These abbreviations are found on the TJC Do Not Use List and ISMP’s List of Error-Prone Abbreviations, Symbols, and Dose Designations due to medication safety issues. They should not be used. You are being tested on them here because these abbreviations may still appear in the pharmacy setting.

^*These abbreviations are found on the TJC Do Not Use List and ISMP’s List of Error-Prone Abbreviations, Symbols, and Dose Designations due to medication safety issues. They should not be used. You are being tested on them here because these abbreviations may still appear in the pharmacy setting.