Introduction

For some patients, solid medications such as tablets and capsules are difficult to swallow, and the physician will order oral liquid preparations. These preparations are usually stated in weight or strength/volume such as milligrams/milliliter. Because liquid medications may be dispensed in either drams from the apothecary system or teaspoons in the household measurement system, conversions among all three measurement systems are often required for dispensing or administering the prescription as written. As with solid medications, these conversions may be accomplished by either ratio and proportion or dimensional analysis. If ratio and proportion is used, then the formula method may be used for preparation of the medication for dispensing. If dimensional analysis is used, the conversion among systems may be accomplished by use of additional ratios for conversion in the equation. Thus the entire conversion and calculation may be completed with one elongated proportional step. (Examples are shown later in this chapter.) Some medications for oral administration are prepared in a powder form for reconstitution to a liquid form before dispensing—the subject of Chapter 9.

Injectable medications may be given when a person is unable to swallow solid medications or when a quicker effect is necessary. Parenteral medications are given by injection into body tissue and may also be given intravenously or directly into the bloodstream. Because solid medications cannot be injected under the skin except as special intradermal forms such as pellets, most injectable medications must be in liquid form. As with oral liquid medications, some parenteral medications come in powders for injection, requiring reconstitution before administration. These medications usually will not be stable in liquid form for an extended period, so they must be handled for stability at the time of administration (reconstitution of parenteral medications is discussed in Chapter 9).

Calculation Of Oral Liquid Medications

Oral medications are available in solid form as discussed in the previous chapter and in liquid form as discussed in this chapter. When oral medications are given in a liquid form, the absorption is usually faster because solids have to dissolve before absorption. The absorption of a medicine is controlled, in part, by the dosage form administered. Most oral medications are absorbed in the small intestine, although some are absorbed beginning in the mouth or stomach. These medications may be administered with oral syringes that are available in 1-mL, 5-mL, and 10-mL sizes (Figure 8-1), a medication cup (Figure 8-2), a dropper that is available in different measurements and is usually tailored by the manufacturer for a specific drug (Figure 8-3), dosage spoons (Figure 8-4), or by using household devices such as teaspoons and tablespoons. The newest form of administration of oral liquid medications is through a nipple or with a pacifier that will hold a measured amount of medication (Figure 8-5). The choice of administration implement for oral liquid medications depends on the volume of medication to be administered and the availability of supplies. Medication cups are found in institutional settings, whereas droppers and oral syringes may be used either in institutions or at home. Teaspoons and tablespoons are the measurements occasionally used for larger doses in the home setting or when the calibrated utensils are not available. The use of kitchen utensils is usually discouraged, because oral syringes and calibrated cups are more accurate.

Liquid medications may be found in tinctures, elixirs, suspensions, and syrups, some of which may be irritating to the gastric system and must be diluted before administration. Some medications such as cough syrups should not be diluted even after the administration; therefore the information about the medication and its use and proper administration is necessary before administering a dose or providing patient education.

Liquid drug preparations are labeled with the strength of the drug (such as milligrams) in the total volume (such as milliliters) of the liquid. Remember that liquid medications may be expressed in metric (milliliters, cubic centimeters, and liters), apothecary (drams and minims), and household (teaspoons, tablespoons, pints, and the like) measurement systems. Doses of medication are also calculated based on strength/volume. This fact is then used to prepare liquid medications for administration. For example, a physician may order amoxicillin 500 mg to be given to a child who requires a liquid dosage form. The medication on hand is amoxicillin 250 mg (weight or strength) per 5 mL (volume). In this case the known amounts will be placed into the formula, ratio and proportion, or dimensional analysis equations for preparing the correct amount of medication. If you need to review the formulas for any of these ways of ascertaining the correct dose to be given or if you need to review the safety measures necessary for medication preparation and administration, return to Chapter 7.

As with the previous chapter, you will calculate doses for competency. You must remember that dose is the amount of medication to be administered at a specific given time, whereas dosage (to be discussed in Chapter 14) is the total amount of medication that will be administered over a particular length of time. Again, as a reminder, the label on the medication must be in the same system of measurement as that found on the prescription or medication order. If these do not agree, conversion should be accomplished to the system found on the label. Also, be sure the medication names are exactly the same, because many drug names look and sound alike.

Calculating Oral Liquid Medications Using Ratio and Proportion

As you learned in Chapter 7, when using the ratio and proportion method of drug calculation, the dose available (DA) and the dosage form (DF) must be one ratio, and the dose ordered (DO) and dose to be given (DG) must be the other ratio in the proportion. With liquids, DF and DG will be in volume, whereas DA and DO will be in strength or weight of drug.

Tech Note

When using this formula to calculate a dose of medication for an oral liquid order, the dose to be given will be in a liquid form such as milliliters (mL) or cubic centimeters (cc). Also remember that if the dose desired and the dose available or on hand are not in the same measurement system, a conversion to the system of the dose available should be made. (See Chapter 4 to review the measurement systems and Chapter 5 for help with conversions between systems.)

Example 8-1

A physician orders amoxicillin 500 mg oral suspension. The medication available is amoxicillin 250 mg/5 mL. How much medication would be administered to the patient for a single dose?

Remember the formula for using ratio and proportion appears as follows:

< ?xml:namespace prefix = "mml" />DA:DF::DO:DG

If you prefer using fractional units for the relationships between the ratios in the proportions, the formula to be used is as follows:

DADF=DODG

Now that you have reviewed the formula, you can calculate the problem given because all of the given measurements are in the metric system.

The DA is 250 mg in the DF of 5 mL. The DO is 500 mg. The proportion is set up as follows:

250mg(DA):5mL(DF)::500mg(DO):x(DG)

OR

250mg(DA)5 ml(DF)=500mg(DO)x(DG)

Either multiply the means versus the extremes or cross-multiply if using the fractional components.

As previously learned, drop the mg because it appears in both sides of the equation, so the equation now appears as follows:

250x=500×5mL

x=500×5 mL÷250or2500mL÷250

x=10 mLor10mL is the prescribed amount of amoxicillin to beadministered to the patient

Try another medication order as an example. Because most oral liquid medications must be calculated to the metric system, the examples are in the metric system.

Example 8-2

A physician orders Ceftin oral suspension 187 mg. The medication on hand is Ceftin 125 mg/5 mL. Because this prescription will be given at home, the medication order for the label should read the amount to be given in household measurements. Again, review Chapters 4 and 5 as needed.

125 mg(DA):5mL(DF)::187mg(DO):x(DG)

OR

Again, either multiply means and extremes or cross-multiply the fractional equivalents as previously accomplished. The resultant formula follows:

125×x=187×5 mLor125x=935 mL

x=7.48or7.5 mL after rounding

Tech Note

Round all doses to a measurable quantity for the utensil being used.

Now change this to the household measurement as requested by the physician.

5mL:1tsp::7.5 mL:x

5x=7.5

Remember that the “mL” designation may be removed because it appears in both equivalents following cross-multiplication.

xtsp=7.5÷5or112

Therefore the dose to be given in household measures is tsp. Remember that household measurements are in fractional units rather than decimal units.

Calculating Oral Liquid Medications Using Dimensional Analysis

Remember that dimensional analysis is really just an elongated form of ratio and proportion using fractional components. To review dimensional analysis as a means of calculating doses, please review Chapter 5. The problem in Example 8-1 would appear as follows for calculation with dimensional analysis:

Example 8-3

A physician orders amoxicillin 500 mg oral suspension. The dosage available is amoxicillin 250 mg/5 mL. How much medication would be administered to the patient for a single dose?

xmL=5mL×500250or2500 mL250 

x=10 mL

Example 8-4

A physician orders Ceftin 187 mg oral suspension. The medication on hand is Ceftin 125 mg/5 mL. Because this prescription will be given at home, the medication order for the label should read the amount to be given in household measurements. With dimensional analysis the problem will have an unknown in teaspoons (x = teaspoons). To obtain the answer in teaspoons, one step of fractional components is added to the calculation, thus eliminating the need for two separate calculations as was necessary with the ratio and proportion or formula methods.

x tsp=187mg1dose×5mL125mg×1tsp5mL

x tsp=187×1125×1

x = 1.49 tsp or 1.5 tsp after rounding to a measurable quantity

The dose to be given is tsp.

Calculating Oral Liquid Medications Using the Formula Method

Remember that the formula method is another means for calculating doses of medications. As with ratio and proportion methods of dosage calculations, the units in the formula are replaced with the desired and known factors. As a review, the formula is as follows:

DD(Dose desired)DH(Dose on hand)×Qty(Quantity/Volume or DF)=DG

Although quantity for oral solid measurements is in capsules or tablets, the quantity in oral liquid medications will be in liquid form, usually in milliliters (mL) in the metric system or teaspoons (tsp) or tablespoons (tbsp) in the household system. The use of dram () in the apothecary system may be used to write prescriptions, but this would not be used when providing the instructions on a medication label for home use. Now take the same problems seen before and calculate using the formula method.

Tech Note

Remember that a dram () is approximately equal to a teaspoon or approximately 5 mL. When converting among systems, use the conversion factor that gives the closest accurate dose. (For further review of conversions among measurement systems, refer to Chapters 4 and 5.)

Example 8-5

A physician orders amoxicillin 500 mg oral suspension. The dosage available is amoxicillin 250 mg/5 mL. How much medication would be administered to the patient for a single dose?

500mg(DD)250mg(DH)×5 mL(Qty)=Dose to be given(DG)

DG=10mL as a single dose

Note that because “mg” is found in both the numerator and denominator, “mg” may be canceled. Also notice that the metric volume measurement has remained in place as the quantity in this formula.

Example 8-6

A physician orders Ceftin 187 mg oral suspension. The medication on hand is Ceftin 125 mg/5 mL. Because this prescription will be given at home, the medication order on the label should read the amount to be given in household measurements.

187 mg(DD)125 mg(DA)×5 mL(Qty)=Dose to be given(DG)

7.48 mL or7.5 mL=DG

Now, by ratio and proportion, complete the desired medication calculation in household measurements.

5xtsp=7.5

Remember that the “mL” designation may be removed because it appears in both equivalents following cross-multiplication.

x tsp=7.5÷5or112

Therefore the dose to be given in household measures is tsp.

Tech Note

Remember that an apothecary dram () is approximately 4 to 5 mL and is considered a teaspoon in the household measurement system because it is not possible to measure 4 mL in a household teaspoon. Always use the conversion that is measurable in the utensil to be used for dose administration.

Using a Medication Cup and Oral Syringe to Measure Oral Liquid Medications

When measuring oral liquid medications using a medicine cup, read the line of the medication to the meniscus at eye level. The meniscus is the curved line that develops on the cup when a medication is poured into the container (Figure 8-6). For medications that must be more accurately measured, an oral syringe should be used. With the oral syringe, the accurate dose is measured from 0.1 mL dose increments in the 1-mL syringe. In the 5-mL and 10-mL oral syringes the increments are in 0.2 mL.

 Tech Alert

Household measurement utensils are sources of potential errors and are not the ideal means of measuring doses. The abbreviations for teaspoon (tsp) and tablespoon (tbsp) can be easily confused, leading to errors in administration. Patient safety is better ensured if calibrated medication administration utensils are used. However, household utensils are used in some necessary instances and understanding these conversions is needed to assist people with proper dosing.

Tech Note

Remember that with oral liquid medication the quantity is given in either weight or strength per volume, not in single tablets or capsules as found with solid preparations. Therefore in most cases, the final volume of medication to be given will be in milliliters.

Practice Problems A

Calculate the following medication orders and answer the questions listed. If there is a dispensing device shown, draw the medication to the correct volume. Show your calculations.

Remember to use the method of calculation and conversion that is most comfortable for you. Choose one conversion system and continue to use it when doing drug calculations.

 1. Ordered medication: dicloxacillin suspension 100 mg po bid

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

2. Medication order: phenobarbital elixir 60 mg po qid

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

3. Prescribed: Diflucan suspension 35 mg po daily

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

4. Prescribed: cephalexin oral suspension 62.5 mg po tid food

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

How would this be administered using household measurements? ____________________

5. Prescribed: docusate sodium syrup 100 mg hs prn dry hard stools

Interpret the order. __________________________________________________________________

Volume of medication to be given with each dose in metric system: ____________________

Volume of medication to be given with each dose in household measurements: ____________________

6. Prescribed: ranitidine syrup 150 mg bid q12h

Interpret the order. __________________________________________________________________

Volume of medication to be given with each dose: ____________________

7. Prescribed: fluoxetine oral solution 10 mg po bid

Interpret the order. __________________________________________________________________

Volume of medication to be given in metric measurements with each dose: ____________________

Volume of medication to be given in household measurements: ____________________

What type of medication administration unit should be given for administration of this dose? ____________________

8. Prescribed: Vibramycin oral suspension 150 mg stat and then 75 mg q12h

Interpret the order. __________________________________________________________________

Initial volume of medication to be given with each initial dose in metric system: ____________________

Initial volume of medication to be given with each initial dose in household measurements: ____________________

Subsequent volume with each subsequent dose to be given in metric system: ____________________

Subsequent volume with each subsequent dose to be given in household measurements: ____________________

9. Prescribed: Lanoxin elixir 75 mcg bid if P ↑ 60

Interpret the order. _____________________________________________________________________

Volume of medication to be given: ____________________________________________

Should this medication be administered with household utensils? ____________________________________________

10. Prescribed: Mellaril oral solution 45 mg bid q12h

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

11. Prescribed: amoxicillin oral suspension 375 mg tid q8h

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

12. Prescribed: Vancocin HCl oral solution 250 mg bid for bacterial infection

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

13. Prescribed: loracarbef oral suspension 160 mg bid for acute bronchitis

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

14. Prescribed: cefaclor oral suspension 250 mg tid food

Interpret the order. __________________________________________________________________

Of the labels provided, which container of cefaclor should be selected for ease of accurate administration for this prescription? ____________________

What is the volume of the medication from the selected medication bottle? __________

15. Prescribed: Duricef oral suspension 0.5 g q6h food

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

16. Prescribed: amoxicillin/clavulanate potassium oral suspension 0.75 g daily in three divided doses

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

17. Prescribed: cephalexin oral suspension 0.375 g tid

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

18. Prescribed: acetaminophen 60 mg q4h prn fever and aching

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

What would the dose be if the physician ordered the medication using the label for a child weighing 33 lb? ____________________

19. Prescribed: V-Cillin K oral suspension 100,000 Units qid food

Interpret the order. __________________________________________________________________

Volume to be given as a dose in metric system: ____________________

How many milligrams of medication are being administered with each dose? ____________________

20. Prescribed: Lorabid oral suspension 50 mg bid

Interpret the label. __________________________________________________________________

Which bottle of medication would be used to prepare this medication for a more accurate administration? ____________________

Volume of medication per dose from the bottle selected in metric system: ____________________

Volume of medication for the above dose from the bottle selected in household measurement: ____________________

Volume of medication for the above dose as found on the label not selected: ____________________

Calculating Parenteral Medications In Vials And Ampules

Parenteral medications are those administered outside the gastrointestinal tract and are usually considered to be those given by injection. These medications may be given directly into the bloodstream (intravenous), into the muscle (intramuscular), beneath the skin (subcutaneous or intradermal) through appropriate parenteral routes. When medications are administered by these means, absorption is typically faster than with most oral medications, with the exception of some slow-release or depot injectables. For the person who cannot swallow medications taken orally or for medications that cannot be administered orally because of absorption incompatibilities, the parenteral route of administration may be used.

Parenteral medications are available in ampules and vials (Figure 8-7) and are most often prepared as a liquid either in an aqueous or oil base by the drug manufacturer. Other medications that are not stable in the liquid form come in powders and crystals that must be reconstituted to a liquid form before being given parenterally. (Chapter 9 discusses the reconstitution of medications.)

As with oral liquid medications, parenteral medications are identified on the container as the strength of the medication in a specific volume of liquid. The strength is usually provided in the metric system—milligrams, grams, and micrograms—and usually in milliliters for volume. The apothecary system’s units of grains per milliliter may also be used, although this is not as common today as previously. (International units are found with some medications, and this unit of measurement is discussed in Chapter 11.)

Some parenterals will also be expressed in percentage strength, but they will usually also have the drug strength per volume in metric measures included on the label. Large doses of parenteral medications may be drawn into syringes holding larger volumes such as 5 mL, 10 mL, 20 mL, and 50 mL per syringe. Tuberculin syringes are calibrated in 0.01-mL increments. Three-milliliter syringes have increments of 0.1 mL. Five-milliliter syringes may have indications for 0.1 or 0.2 mL, whereas the larger syringe volumes are usually marked with 0.2-mL increments except in syringes holding more than 20 ML and depending on the total volume that can be measured in the specific syringe. The choice of syringe size is based on the amount of medication that is to be administered.

Once the parenteral medication has been calculated, the correct syringe must be chosen according to the volume of medication to be administered. If the volume of medication has a dose of less than 0.1 mL or is in increments of tenths of a mL, such as 0.25 mL, it should be measured with a tuberculin syringe (Figure 8-8). Syringes for larger volumes are chosen by the amount of medication to be either administered or added to intravenous fluids. A 3-mL syringe is the usual choice for medication volumes between 1 mL and 3 mL or when medications can be measured in tenths of milliliter above 0.1 mL, such as 0.3 mL or 1.9 mL (Figure 8-9). As seen in this figure, on some syringes that are manufactured with the needle attached, the needle has a safety cap as required by Occupational Safety and Health Administration regulations. The measurement of medications in larger syringes is not as accurate and is shown in 0.2 mL (Figure 8-10). The selection of the correct syringe depends on the volume of medication dose and the precision of the accurate dose. Note that medication volumes are measured with the bottom of the rubber stopper of the plunger placed at the calibration mark of the syringe for the correct fluid level of the medication. For example, in Figure 8-11 the volume would be 1.7 mL and in Figure 8-12 the volume would be 2.3 mL.

Drugs in vials—those sealed with a rubber-top—are for single- or multiple-dose use, whereas ampules—sealed glass containers—are for single doses. Powders for reconstitution may be in either multiple-dose or single-dose vials or even in Act-O-Vials (Figure 8-13). Ampules contain only single doses of medications and should never be “saved” for future use because no means are available to ensure maintenance of sterility. Liquids used for reconstitution may be supplied in either vials or ampules as designated by the manufacturer.

When looking at the label for liquid injectable medications in vials, you will find that the labels appear similar to the labels for oral liquid medications, but the total dose amount of medication for administration will generally be a smaller volume or the solution will be more concentrated. Because medications given by injection under the skin or into muscle can be only small amounts, the total volume of medication for injectables will most likely be 0.5 mL to 3 mL. Larger volumes of medication (>3 mL) are not easily absorbed in the muscle or subcutaneous tissue; therefore these amounts must be divided into smaller individual doses that require multiple injection sites.

The rules for calculating parenteral doses are the same as those for oral liquid medications. The same formulas are used, and the calculations are the same except usually the dose volume is not as large. Importantly, when parenteral medications are calculated, the correct strength of medication per volume is used in the calculation, not the total volume of the container unless the container is a single-use ampule or vial.

Practice Problems B

The following problems are designed to help you correctly read a syringe.

1. The amount in the syringe is ________________________________________________________

2. The amount in the syringe is ________________________________________________________

3. The amount in the syringe is ________________________________________________________

4. The amount in the syringe is ________________________________________________________

5. Indicate 3.6 mL.

6. Indicate 0.64 mL.

7. Indicate 6.8 mL.

8. Indicate 1.8 mL.

9. Indicate 2.4 mL.

Should this syringe be used for accurate measurement for this amount of medication? ____________________

Explain your answer. ________________________________________________________________

10. Indicate 8.6 mL.

Practice Problems C

Use the method of calculation with which you are most comfortable to complete these problems. Refer to the formulas found with oral liquid medications as needed, but use only one method until proficiency has been met. If you need assistance converting within a measurement system or among measurement systems, refer to Chapters 4 and 5. As always, show your calculations.

1. Prescribed: morphine sulfate 15 mg IM q4h prn pain

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

2.  Prescribed: prochlorperazine 10 mg IM q6h prn N&V

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

3. Prescribed: tobramycin 60 mg IM q8h

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

4. Prescribed: vitamin B₁₂ 0.2 mg IM qwk

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

Can the medication vial shown be used to fulfill the order? ____________________

Explain your answer: ____________________

5. Prescribed: meperidine 75 mg IM q4-6h prn pain

Interpret the order. __________________________________________________________________

Which vial of meperidine is the best choice to be used? ____________________

Why did you choose the vial that is to be used? ____________________

Volume of medication to be given with the dose of the medication chosen: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

6. Prescribed: benztropine mesylate 1 mg IM daily

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

Show the amount of medication on the syringe supplied.

7. Prescribed: Cogentin 1.5 mg IM daily

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

8.  Dose ordered: AquaMEPHYTON 2 mg stat

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

9. Prescribed: Amikin 250 mg IM q8h

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

10. Prescribed: Kantrex 125 mg IM q12h until discontinued

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

11.  Prescribed: Vistaril 75 mg and meperidine 50 mg IM q6h prn pain

Interpret the order. __________________________________________________________________

Volume of Vistaril that will be given in a dose: ____________________

Volume of meperidine to be given in a dose: ____________________

Show the amount of combined medication on the syringe supplied:

12.  Prescribed: Cleocin phosphate 0.25 g IM stat then q8h

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

13. Prescribed: lincomycin 0.45 g IM stat

Interpret the order. __________________________________________________________________

Volume of medication needed for the order: ____________________

14. Prescribed: Solu-Cortef 125 mg IM stat

Interpret the order. __________________________________________________________________

Volume of medication needed for a dose: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

15. Prescribed: Depo-Provera 0.3 g IM qmo

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

16. Prescribed: Luminal gr IM prn rest

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose: ____________________

Strength of medication to be given in the metric system: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

17. Prescribed: codeine phosphate gr IM prn pain

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

Strength of medication to be given in the metric system: ____________________

18. Prescribed: phenobarbital sodium gr IM q4h prn agitation

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose: ____________________

Strength of medication in metric system: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

19. Prescribed: aminophylline 125 mg IV q6h

Interpret the order. __________________________________________________________________

Volume of medication to be given with a single dose: ____________________

20. Prescribed: Tagamet 75 mg IM q6h

Interpret the order. __________________________________________________________________

Volume of medication to be given with a single dose: ____________________

Choose the correct syringe(s) and show the amount of medication on the syringe(s).

Review

As with the previous chapter, on the calculation of oral solid medications, this chapter shows how to calculate the dose desired for parenteral and oral liquid medications. The same methods for calculation—ratio and proportion, dimensional analysis, and formula methods—are used for these calculations. These medications are then dispensed in the measurements for liquids in the three systems—metric, household, and apothecary. Conversions for the correct volume of medication depend on the measurement system to be used for administration. The household system is often used for home delivery of oral medications: when a more accurate utensil for administration is not provided. The metric and apothecary systems are most often used with inpatient settings, especially with parenteral medications. If the medication is to be given parenterally, the correct syringe and needle must be chosen. Liquid oral medications may be administered from a medicine cup, dose spoon, dose syringe, medicine dropper, or medication pacifier depending on the volume of medication and the age and ability to take medication of the patients. In some instances, liquid medications may be combined with oral or with parenteral administration. In those instances the correct dose amount for each medication must be properly calculated and prepared in the appropriate administration container. As with all medications, the proper calculation and appropriate containers for parenteral and oral liquid medications are important for patient safety. Patient safety should always be the utmost concern when preparing and delivering medications.

Posttest

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

Using the following labels, interpret the orders and calculate the ordered medications. Figure the dose to be given in the dose form and indicate the form in the answer. Show all calculations. Round to the nearest tenth after completing all calculations, unless marked with an asterisk, and then round to the nearest hundredths. Always be sure the answer is a measurable volume.

1. Prescribed: Stadol 1 mg stat then q4h

Interpret the order. __________________________________________________________________

Volume of medication to be given as a single dose: ____________________

Choose the correct syringe and show the amount of medication on that syringe.

2. Prescribed: phenobarbital elixir gr q4h for epilepsy

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose in metric system: ____________________

Volume of medication to be given in apothecary system: ____________________

3. Prescribed: penicillin V potassium oral solution 0.25 g po qid

Interpret the order. __________________________________________________________________

Volume of medication to be given with a dose in metric system: ____________________

Volume of medication to be given in household measurements with each dose: ____________________

Indicate the amount of medication in the medication cup.

4. Prescribed: Keflex oral suspension 32 mg q6h

Interpret the order. __________________________________________________________________

Volume of medication to be given in metric units for each dose: ____________________

Indicate the amount of medication in the correct utensil for administration.

5. Prescribed: Garamycin 0.06 g IM q8h

Interpret the order. __________________________________________________________________

Volume of medication to be given in metric system for each dose: ____________________

Indicate the correct amount of medication on the appropriate syringe.

6. Prescribed: scopolamine gr 1/150 subcutaneously 30 min before surgery

Interpret the order. __________________________________________________________________

Volume of medication to be given in metric system: ____________________

7. Prescribed: Solu-Medrol 37.5 mg IM stat

Interpret the order. __________________________________________________________________

Volume of medication to be given: ____________________

Indicate the correct amount of medication on the appropriate syringe.

8. Prescribed: Mellaril oral solution 45 mg bid

Interpret the order. __________________________________________________________________

Volume of medication to be given with each dose: ____________________

Indicate the amount of medication in the correct utensil for administration.

9. Prescribed: diazepam 2 mg IM stat and then q6h prn for anxiety

Interpret the order. __________________________________________________________________

Volume of medication to be given as a single dose: ____________________

10. Prescribed: amoxicillin oral suspension 125 mg q8h

Interpret the order. __________________________________________________________________

Volume of medication to be given as a dose in metric system: ____________________

Volume of medication in household measurements: ____________________

Indicate the amount of medication in the most accurate utensil for administration.

11. Prescribed: Zantac syrup 75 mg bid 30 min ac meals

Interpret the order. ________________________________________

Volume of medication to be given with a dose in the metric system: ____________________

Volume of medication to be given with each dose in household measurements: ____________________

Indicate the volume of medication on the utensils to be used for administration.

12. Prescribed: Cipro 0.4 g IV q12h

Interpret the order. __________________________________________________________________

Metric volume of medication for each dose that will be added to an IV bag for administration: ____________________

13. Prescribed: Dilaudid 500 mcg IM q4h prn severe pain

Interpret the order. __________________________________________________________________

*Volume of medication to be given with each dose in metric system: ____________________

Indicate the amount of medication on the correct syringe for administration.

14. Prescribed: digoxin 0.1 mg IM stat then daily

Interpret the order. __________________________________________________________________

Volume of medication to be given in a dose in metric system: ____________________

15. Prescribed: Duricef 750 mg po stat then 0.5 g q12h

Interpret the order. __________________________________________________________________

Which drug bottle should be used? ____________________

Volume of medication to be given in stat dose in metric system: ____________________

Volume of medication to be given in stat dose in household system: ____________________

Volume of medication to be given q12h in metric system: ____________________

Volume of medication to be given q12h in household measurements: ____________________

Indicate the correct amount of medication on the appropriate utensil for each administration.

16. Prescribed: dicloxacillin suspension 100 mg po q6h for acute bronchitis

Interpret the order. __________________________________________________________________

Metric volume of medication to be given as a dose: ____________________

What is the volume of medication in household measurements? ____________________

17. Prescribed: secobarbital sodium gr IM prn sleep

Interpret the order. __________________________________________________________________

Volume of medication to be given as a single dose: ____________________

Indicate the amount of medication on the correct syringe for administration.

18. Prescribed: Garamycin 30 mg IM q8h

Interpret the order. __________________________________________________________________

*Volume of medication to be given as a dose: ____________________

19.  Lasix 20 mg IM q4h

Interpret the order. __________________________________________________________________

Volume of medication to be given as a single dose: ____________________

Indicate the amount of medication on the correct syringe for administration.

20.  meperidine 50 mg IM q4h prn pain

Interpret the order. __________________________________________________________________

Which container of meperidine would you choose to use? ____________________

Volume of medication to be given from the vial of medication selected: ____________________

*Volume of medication to be given from the other vial of medication: ____________________