Oral Drug DosagesOral Drug Dosages - JustAnswer...Feb 10, 2012 · volves the mixing of solutions...

Oral Drug DosagesOral Drug Dosages

Tablets and CapsulesOral LiquidsAlligation

4. Use the formula to calculate drug dosage.

5. Calculate liquid drugs by using alligation.

DH* Q = X

G L O S S A R Yalligation A method of solving problems using arithmetic that in-

volves the mixing of solutions or mixtures of solids possessing dif-ferent percentage strengths.

O B J E C T I V E SUpon completion of this chapter, the student should be able to:

1. Identify equipment for the medication, dosage, and delivery oforal drug administration.

2. Measure drugs using the calibrations on the equipment.3. Calculate the amount of the drug to be given.

O U T L I N EOverviewEquipment Used in Oral Dosage Measurement

Medicine CupsCalibrated DroppersCalibrated SpoonsOral Syringes

9

1428344225, Pharmaceutical Calculations for Pharmacy Technicians: A Worktext, by Jahangir Moini, MD, MPH - ©Thomson

CHAPTER 9 Oral Drug Dosages 79

OVERVIEW

There are many different forms of medication that can beadministered orally, which include tablets, capsules, andliquids. Administration of medications by mouth is abbre-viated as “p.o.,” which comes from the Latin phrase “peros.” The oral route is the most convenient and usually thesafest and least expensive route of medication administra-tion. It is the one most often used. However, it has limita-tions because of the way a drug typically moves throughthe digestive tract.

EQUIPMENT USED IN ORAL DOSAGEMEASUREMENT

Pharmacy technicians should be familiar with calibrationsof devices that are used in the calculation of dosages. Theoral utensils that are used include the medicine cup, cali-brated droppers and spoons, and oral syringes. There arealso various pediatric syringes such as 1 mL and 3 mLsized syringes.

Medicine CupsMedicine cups are plastic and measure up to 1 fluidounce, or its equivalent. They are the most common typeof device used to measure liquids for oral administration.Figure 9-1 shows the 30 mL and 1 oz. medicine cups thatare the approximate equivalents of the metric, apothecary,and household systems. The calibrations for milliliters,tablespoons, teaspoons, ounces, and drams appear in thisfigure.

Calibrated DroppersCalibrated droppers are used to measure and administersmall amounts of liquid medication via the oral route.

Droppers are commonly used to deliver certain medica-tions to the eyes, ears, and nose. They are also used for oralpediatric doses. Droppers are used for liquid medicationsthat are less than 2.5 mL. Figure 9-2 shows the calibrateddropper.

The amount of one drop may vary according to the di-ameter of the hole at the tip of the dropper. It is calibratedaccording to the way the drug is ordered. Medications aregiven in milliliters, cubic centimeters, or drops (Figure 9-3).

Calibrated SpoonsCalibrated spoons are usually used with pediatric or eld-erly patients. There are various sizes for calibrating differ-ent doses (Figure 9-4).

1 TBS

2 TSP

1 TSP1/2 TSP

15 ML

10 ML

5 ML

1 OZ

3/4 OZ

1/2 OZ

1/4 OZ

1/8 OZ

8 DR

6 DR

4 DR

2 DR1 DR

7.5 ML

2.5 ML

20 ML25 ML

30 ML2 TBS

Figure 9-1. Medicine cup with approximate equivalentmeasures.

Figure 9-2. Calibrated dropper.

Figure 9-3. Furosemide Oral Solution label. (Used withpermission of Roxane Laboratories, Inc.)

Medicine Cupsto 1 fluid

n

tions to the eyes, ears, and nose. They are also us

ppers and spus pediatric sges

ns, and oral syrringes such as 1

nges. There aremL and 3 mL

rated dropper.gure 9-2. Cal

brated dralso ized

d for ora


80 CHAPTER 9 Oral Drug Dosages

TABLETS AND CAPSULES

For drugs that are administered orally, absorption may be-gin in the mouth and stomach, but usually most of thedrug is absorbed from the small intestine. When a drug istaken orally, food and other drugs in the digestive tractmay affect how much and how fast the drug is absorbed.Thus, some drugs should be taken on an empty stomach.Others should be taken with food. Some drugs should notbe taken with certain other drugs, and still others cannotbe taken orally at all.

When a prescriber orders medications in tablet or cap-sule form, the pharmacy technician must determine if thestrength or dosage on hand is the same strength as thedosage ordered or in multiples of the dosage ordered.Sometimes patients should divide the tablet in half or intoquarters. Figure 9-6 shows Biaxin tablets in two differentstrengths.

Oral SyringesOral syringes are also calibrated for mL (cc) and tea-spoons. These devices are used when medication dosagesare less than 5 mL. Oral syringes have a different shapeand size compared to hypodermic syringes. They may betinted in color, whereas hypodermic syringes are clear(Figure 9-5).

Figure 9-4. Calibrated spoon.

Figure 9-5. Oral syringe.

EXAMPLE 1:The doctor’s order reads: Biaxin 500 mg p.o.q12h.Biaxin comes in tablet strengths of 250milligrams per tablet (or filmtab), and 500milligrams per tablet. When both strengths areavailable, the pharmacy technician should selectthe 500-milligram strength, and give one wholetablet for each dose.

EXAMPLE 2:The order reads: Klonopin 1.5 mg p.o. t.i.d.Klonopin comes in strengths of 0.5 mg, 1 mg,and 2 mg tablets (Figure 9-7). When the threestrengths are available, the pharmacy technicianshould select one 1 mg tablet and one 0.5 mgtablet (1 mg � 0.5 mg � 1.5 mg). This providesthe ordered dosage of 1.5 mg and is the leastnumber of tablets (2 tablets total) for the patientto swallow. However, another option would be to give three 0.5 mg tablets, which also equal1.5 mg.

al Syringes

ringe.9-5.



Figure 9-6. Biaxin 250 mg and 500 mg tablets. (Courtesy of Abbott Laboratories)

(A)

(A)

(B)

(C)

(B)

Figure 9-7. Klonopin 0.5 mg, 1 mg, and 2 mg tablets. (Courtesy of Roche Laboratories, Inc.)



Another option for the pharmacy technician is tohalve the 2 mg tablets to obtain two 1 mg parts,and pair one-half with a 0.5 mg tablet. Thiswould also equal 1.5 mg, and would amount to1 1/2 tablets. However, cutting any tablet in halfmay produce slightly unequal halves. It ispreferable to give whole, undivided tablets whenthey are available.

In some instances it may be necessary to convert be-tween systems of measurement in order to accurately cal-culate the dosage. In Chapter 8, you learned a formula fordosage calculations, as follows:

To convert dosages, ensure that all measurements are inthe same system of measurement and the same size unit ofmeasurement. If not, convert before proceeding.

D (desired)

H (have)* Q (quantity) = X (amount)

D

H* Q = X

EXAMPLE 3:The drug order reads: Ampicillin 0.5 g p.o. q6h.Available on hand: Ampicillin 500 mg percapsule.This medication order is written and supplied inthe same system (metric) but in different size units(g and mg). A drug order written in grams butsupplied in milligrams will have to be convertedto the same size unit. You must convert 0.5 gramto milligrams, as follows:1 g � 1000 mgRemember, you are converting from a larger to asmaller unit. Therefore, you will multiply by theconversion factor of 1000, or move the decimalpoint three places to the right.0.5 g � 0.5 � 1000 � 500 mg, or 0.5 g �0.500 � 500 mg�

Order: Ampicillin 500 mg p.o. q6hOn hand: Ampicillin 500 mg per capsuleYou would give the patient one ampicillin 500mg capsule by mouth every 6 hours.

EXAMPLE 4:The drug order reads: Lopressor 100 mg p.o.b.i.d.

(Courtesy of Novartis)

EXAMPLE 5:The drug order reads: V-Cillin K 0.5 g p.o. q.i.d.Available on hand: V-Cillin K 250 mg per tabletHow many tablets should you give to the patientper dose?

(Copyright of Eli Lilly and Company. Used with permission.)

As you know, 1g � 1000 mg0.5 g � 0.5 � 1000 � 0.500 � 500 mg

�

Now you have the ordered drug and the on-handdrug measured in the same size units.Ordered: V-Cillin K 0.5 g � 500 mgOn hand: V-Cillin K 250 mg tablets

� 1 tablet � 2 � 1 tablet � 2 tablets,

given orally 4 times daily

500 mg250 mg

The medication container is labeled “Lopressor50 mg per tablet.”Calculate one dose:

� 2 tablets, given orally, twice daily

100 mg50 mg

=2 mg1 mg

* 1 tablet = 2 * 1 tablet

DH* Q =

100 mg50 mg

* 1 tablet

EXAMPLE 3:6h

,of measuremennot, convert b

and the same sifore proceeding.

unit of

C f N

same systememe



EXAMPLE 6:The drug order reads: Codeine sulfate gr 3/4

p.o. q4h p.r.n., pain.The drug on hand is: Codeine sulfate 30 mg

per tablet.Calculate one dose.

gr I � 60 mg

gr � 3/4 � 3/4 � 60 � � 45 mg

Therefore, order: Codeine gr 3/4 � 45 mgThen calculate:

Tablets are to be given every 4 hours as neededfor pain.

= 1 12

tablets

DH* Q =

4530* 1 tablet =

32

tablets

3 * 604

(Used with permission of Roxane Laboratories, Inc.)

EXAMPLE 7:The order is: Synthroid 0.05 mg p.o. q.d.25 mcg tablets are available. How many tabletswill you give?

(Courtesy of Knoll Pharmaceutical Company)

1 mg � 1000 mcg. Conversion factor is 1000.0.05 mg � 0.05 � 1000 � 0.050 � 50 mcg

�

Order: Synthroid 0.05 mg � 50 mcgOn hand: Synthroid 25 mcg tabletsNow you can calculate:

� 2 tablets, given

orally once a day

DH* Q =

50 mcg25 mcg

* 1 tablet

EXAMPLE 8:A patient uses codeine gr ii orally. The label onthe available codeine bottle tells you that eachtablet provides 30 mg. How much will you givethe patient?

(Used with permission of Roxane Laboratories, Inc.)

* Q =30* 1 tablet =

32

tablets 0.05 mg 0.05 � 1000 0.050

r � 3/4 � 3/

herefore orde

4 � 6

Codeine gr 3/

3 * 64

� 45 mg

� 45 mg

oll Pharmaceutical Courtesy of Kn ompany)



STOP AND REVIEWSTOP AND REVIEW

Calculating Dosages of Tablets and Capsules

1. Calculate the correct number of tablets or capsules tobe administered per dose. Tablets are scored.a. Ordered: Telithromycin 800 mg p.o. q.d.

On hand: Telithromycin tablets 400 mgGive: ____________________

b. Ordered: Pravachol 20 mg p.o. q.h.s.On hand: Pravachol 10 mg tabletsGive: ____________________

c. Ordered: ferrous sulfate (FeSo4) 300 mg p.o. q.d.On hand: ferrous sulfate tablets 5 gr (324 mg)Give: ____________________

d. Ordered: Codeine 60 mg p.o.; q3h p.r.n.On hand: Codeine tablets 15 mg (1/4 gr)Give: ____________________

e. Ordered: Nitroglycerin 1/150 gr S.L. p.r.n.On hand: Nitrostat tablets 0.4 mg (1/150 gr)Give: ____________________

f. Ordered: Quinidine 0.6 g p.o. q4hOn hand: Quinidine 200 mg tabletsGive: ____________________

g. Ordered: Prednisone 7.5 mg p.o. q.d.On hand: Prednisone 5 mg scored tabletsGive: ____________________

h. Ordered: Aldomet 250 mg p.o. b.i.d.On hand: Aldomet 125 mg tabletsGive: ____________________

i. Ordered: Duricef 0.5 g p.o. b.i.d.On hand: Duricef 500 mg tabletsGive: ____________________

j. Ordered: Coumadin 5 mg p.o. q.d.On hand: Coumadin 2 mg scored tabletsGive: ____________________

Approximate equivalent gr 1 � 60 mg. Theconversion factor is 60.

Ordered: Codeine gr ii orally p.r.n., painOn hand: Codeine 30 mg tabletCalculate how much you will give as needed forpain:DH* Q =

120 mg30 mg

= 4 tablets

gr 160* 60 =

6060= 1 mg

2. Calculate one dose for each of the medication orders inquestions a through i. The labels lettered A through Iare the drugs you have available. Indicate the lettercorresponding to the label you select.a. Order: verapamil sustained release 240 mg p.o. q.d.

Select: _____Give: _____

b. Order: carbamazepine 0.2 g p.o. t.i.d.Select: _____Give: _____

c. Order: Lopressor 50 mg p.o. b.i.d.Select: _____Give: _____

d. Order: potassium chloride 16 mEq p.o. q.d.Select: _____Give: _____

e. Order: Procanbid 1 g p.o. q6hSelect: _____Give: _____

f. Order: cephalexin 0.5 g p.o. q.i.d.Select: _____Give: _____

g. Order: levothyroxine sodium 0.2 mg p.o. q.d.Select: _____Give: _____

h. Order: digoxin 0.5 mg p.o. q.d.Select: _____Give: _____

i. Order: allopurinol 0.1 g p.o. t.i.d.Select: _____Give: _____

j. Order: procainamide hydrochloride 1000 mg q6hSelect: _____Give: _____



(B) (Courtesy of G. D. Searle and Company)

(A) (Courtesy of Mylan Pharmaceuticals Inc)

(C) (Courtesy of Monarch Phamaceuticals) (continues)



(E) (Copyright Eli Lilly and Company. Used with permission.)

(F) (Courtesy of Novartis)

(D) (Courtesy of Knoll Pharmaceutical Company)

(continued)



(G) (Reproduced with permission of GlaxoSmithKline)

(H) (Courtesy of Novartis)

(I) (Courtesy of Ciba-Geigy Corporation)



ORAL LIQUIDS

Oral liquids are usually ordered for children, elderly peo-ple, or patients who are not able to swallow tablets orcapsules. Each oral liquid contains a specific amount ofmedication in a given volume as written on the label(Figures 9-8A through C, listed next).

In solid form, the drugs can be calculated by the num-ber of tablets or capsules that contain the prescribeddosage. In liquid form, pharmacy technicians must calcu-late the volume of the liquid that contains the prescribeddosage of the drug. The supply dosage is written on the la-bel, indicating the amount of drug per 1 mL of solution;example amounts are as follows: 125 mg per 5 mL, 250mg per 5 mL, or 375 mg per 5 mL.

Figure 9-8. Oral liquid: (A) Ceclor 125 mg per 5 mL; (B) Ceclor 250 mg per 5 mL; and (C) Ceclor 375 mg per 5 mL (Copyright Eli Lilly andCompany. Used with permission.)

(A)

(B)

(C)



You realize that in both Example 1 and Example 2, thesupply quantity is the same (5 mL), but the dosagestrength (weight) of the drug is different (125 mg per 5 mLvs. 250 mg per 5 mL) because of each liquid’s concentra-tion. The more concentrated solution must be given to thepatient, offering less volume per dose for the same dosage.

EXAMPLE 1:The prescriber orders Ceclor 100 mg p.o. q.i.d.To calculate this prescription, look at the label ofCeclor available in Figure 9-8A.You should choose Ceclor 125 mg per 5 mL.

given orally 4 times a day

100 mg125 mg

* 5 mL =45* 5 mL =

205= 4 mL

DH* Q = X

EXAMPLE 2:If you select the same drug order as in Example1, Ceclor 100 mg p.o. q.i.d., as a strongersolution (Ceclor 250 mg per 5 mL), you mustcalculate as follows:

given orally 4 times a day

25* 5 mL = 2 mL

DH* Q =

100 mg250 mg

* 5 mL


Calculating Liquid Dosages

1. Calculate the following drugs ordered for one dose.a. Ordered: Zovirax susp 400 mg p.o. b.i.d.

On hand: Zovirax 200 mg / 5 mL suspension 10 mLGive: ____________________ mL

b. Ordered: Artane 3 mg p.o. t.i.d. a.c.On hand: Artane Elixir 2 mg / 5 mLGive: ____________________ mL

c. Ordered: Depakene syrup 125 mg p.o. q12hOn hand: Depakene syrup 250 mg / 5 mLGive: ____________________ mL

d. Ordered: Amoxil 100 mg p.o. q.i.d.On hand: 80 mL bottle suspension (125 mg per 5 mL)Give: ____________________ mL

e. Ordered: Zofran 8 mg p.o. b.i.d.On hand: Zofran liquid 4 mg / 5 mLGive: ____________________ mL

f. Ordered: Compazine syr 10 mg p.o. t.i.d.On hand: Compazine syrup 5 mg / 5 mLGive: ____________________ mL

g. Ordered: erythromycin suspension 600 mg p.o. q6hOn hand: erythromycin 400 mg / 5 mLGive: ____________________ mL

h. Ordered: Ceclor suspension 225 mg p.o. b.i.d.On hand: Ceclor suspension 375 mg per 5 mLGive: ____________________ mL

i. Ordered: Dilantin-125 150 mg p.o. b.i.d.On hand: Dilantin-125 suspension 125 mg / 5 mLGive: ____________________ mL

j. Ordered: digoxin elixir 0.25 mg p.o. q.d.On hand: digoxin elixir 50 mcg / mLGive: ____________________ mL

k. Ordered: Pepcid 20 mg p.o. q.i.d.On hand: Pepcid 80 mg / 10 mLGive: ____________________ mL

l. Ordered: Grifulvin V 500 mg p.o. b.i.d.On hand: Grifulvin V suspension 125 mg / 5 mLGive: ____________________ mL

m. Ordered: Mycostatin 250,000 U p.o. q.i.d.On hand: Mycostatin 100,000 units per mLGive: ____________________ mL

n. Ordered: Dicloxacillin: 100 mg q.i.d.On hand: Dicloxacillin 62.5 mg per 5 mLGive: ____________________ mL

o. Ordered: Augmentin 0.5 g, p.o. t.i.d.On hand: Augmentin 250 mg / 5 mLGive: ____________________

p. Ordered: Vistaril 10 mg p.o. q.i.d.Give: ____________________

q. Ordered: Keflex 50 mg p.o. q.i.d.Give: ____________________

(continues)



(continued)

(A) (Label reproduced with permission of Pfizer Inc.)

(B) (Courtesy of Dista Products Company)

r. Ordered: Lanoxin elixir 0.25 mg p.o. q.d.Give: ____________________ mL

(Reproduced with permission of GlaxoSmithKline) (Courtesy of Purdue Pharma L.P.)

s. Ordered: OxyFast (oral solution concentrate) 15 mgp.o. q.i.d. p.r.n.

Give: ____________________ mL



(Courtesy of Abbott Laboratories)

t. Ordered: Valproic acid 0.5 g p.o. t.i.d.Give: ____________________ mL

(Courtesy of Abbott Laboratories)

u. Ordered: Biaxin 75 mg p.o. b.i.d.Give: ____________________

ALLIGATION

Alligation is defined as a method of arithmetic that involvesthe mixing of solutions or mixtures of solids possessing dif-ferent percentage strengths. Sometimes it is necessary to ob-tain the desired strength of a medication by compounding,mixing higher and lower concentrations of medications inorder to be able to fill a specific prescription or medicationorder. This method is known as “alligation alternate” and of-fers a rapid method of calculation that is useful to pharma-cists and pharmacy technicians. All concentrations must bein a percentage form and the strength of the desired solutionmust lie between the stronger and weaker solutions avail-able. In other words, the final mixture will be an average ofthe individual strengths. These will be calculated as pro-

portional parts. If the concentration is not expressed in thepercentage form, it must be converted to the percentageform. For example, a solution strength expressed as 1 : 200must be converted to a percentage.

By using alligation, the number of parts of each compo-nent needed to prepare the correct percentage concentra-tion may be calculated. Lines are drawn during calculationto bind quantities together. The substance with a highervalue than what is required is the one with the loweramount. The increase in the value or amount of one of thesubstances balances the decrease in value or amount of theother substances.

1

200* 100 = 0.5%



EXAMPLE 1:The quantities of the higher and lowerpercentages of products may be achieved byusing the following formula:

XTotal Quantity for Compounding

LOWER quantity: Number of LOWER PartsTotal Number of Parts

=

XTotal Quantity for Compounding

HIGHER quantity: Number of HIGHER PartsTotal Number of Parts

=

EXAMPLE:Percentage of products available PartsHIGHER Higher – Desired

DESIREDLOWER Lower – Desired

TOTAL PARTS

The upper and lower right corners of the X-shaped dia-gram are achieved by calculating the difference betweenthe higher percentage and the desired percentage as wellas between the lower percentage and the desired per-centage. The difference between these two figures isplaced in the upper right corner of the “X.” Then, byadding the higher and lower parts, the total number ofparts is calculated.

Alligation is useful in solving any type of dilution orconcentration problem. Concentrations expressed in mg/mL, ratios, and even mixtures of liquids of known specificgravities may be solved using alligation. The strengths ofthe preparations being mixed, as well as the final mixture,have to be expressed in a common denomination whenthe alligation formula is being set up. When diluting apreparation, the diluent’s strength is considered as 0%.When the strength of a mixture is increased by addingmore drug, the strength of this component is 100%. Thefinal proportion allows a distinct correlation between the parts in the mixture and any specific denominationneeded.

Remember

• Use alligation to determine the proper mixtures ofsolutions or solids with different percentage strengths.

• By using alligation the final mixture will be an average ofthe individual strengths expressed as a percentage.

• The substance with a higher value than what is required isthe substance with the lower amount.

• The increase in value of one of the substances balancesthe decrease in value of the other substances.

• Calculate the upper and lower right corners by calculatingthe difference between the higher percentage and thepercentage desired.

• Add the higher and lower parts to determine the totalnumber of parts.

EXAMPLE 2:To find what proportion is required for apreparation containing 70% alcohol mixed withanother that contains 20% alcohol, to produce amixture of 35% strength, the following steps aretaken:Percentages Parts70% ______

35%20% ______Remember,Higher concentration parts � 35 � 20 � 15Lower concentration parts � 70 � 35 � 35Percentages Parts70% 15 parts HIGHER

35%20% 35 parts LOWER

50 PARTS TOTALTherefore, the result will be as follows:70% :

X � 300 mL of 70% solution

20% :

X � 700 mL of 20% solution3550=

X mL1000 mL

1550=

X mL1000 mL

EXAMPLE 3:To find what proportion is required for apreparation containing 10% of a drug mixedwith another that contains 15% of a drug, toproduce a mixture of 12% strength, the followingsteps are taken:

0%.hen the strength of a mixture is increased by adding

The

35%

solved using abeing mixed, ssed in a com

ligation. The strwell as the finalon denomina

pngths ofmixture,n w

% strength, the fomixture of 3, p

owing steps a

P

, ,vities may be

parabe



A. Understand that the 10% drug is 2% tooweak. The 15% drug is 3% too strong. Theexcess strength of 3 parts of the stronger drugcan be calculated to balance the deficientstrength of 2 parts of the weaker drug, asfollows:15% minus 2 Parts of 15%

from12%10% 3 Parts of 10%

_________________________________________________________________________5 Parts of 12%The figure obtained from 12% � 10% is placedacross from 15% on the right side of theequation. This is labeled as “2 parts of 15%.”The figure obtained from 15% � 12% is placedacross from 10% on the right side of theequation. This is labeled as “3 parts of 10%.”This calculation produces a drug mixture of “5parts of 12%,” which is the desired strength.Alligation calculations used to mix solutions maybe checked by using the following formula:milliliters � percent (as a decimal) � grams

EXAMPLE 4:Prepare 250 mL of dextrose 7.5%. To do this,you are required to use dextrose 5% (D5W) anddextrose 50% (D50W). Determine how manymilliliters of each will be required.50 _____

7.55 _____As discussed previously, subtract the centernumber from the upper-left number and put it atthe lower right. Then, subtract the lower-leftnumber from the center number, and put it at theupper right.50 2.5

7.55 42.5The sum of the two numbers written at the rightside of the equation, 2.5 � 42.5, equals 45,which is the total number of parts of the 7.5%solution. Put in the terms of ratios, the ratio of the5% solution to the 7.5% solution is 42.5 : 45.The ratio of the 50% solution to the 7.5%solution is 2.5 : 45. Therefore, much less of the

50% solution is needed to make the 7.5%solution.To calculate the volume needed of each dextrosesolution, use the following equations:50% Dextrose

x mL � 13.89 mL D50W5% Dextrose

x mL � 236.11 mL D5WAdd the volumes of the two solutions; the sumshould equal the required volume of 7.5%dextrose.236.11 mL

� 13.89 mL__________250.00 mL

Check your answer using the formula below. Thenumber of grams of solute should equal the sumof the grams of the solutes of the 50% solutionand the 5% solution.mL � % � g250 mL � 0.075 � 18.75 g 13.89 mL �0.5 � 6.945 g250.11 mL � 0.05 � 11.805 gNow, add:

11.805 g�6.945 g_________18.750 g

x mL =(42.5) * 250 mL

45 parts

x mL42.5 parts

=250 mL45 parts

x mL =(2.5 parts) * 250 mL

45 parts

x mL2.5 parts

=250 mL45 parts


Alligations

1. There are 10% and 3% of ammoniated mercuryointment available. A technician needs to prepare 450 gof a 5% ointment. How many grams of each of the 10%and 3% ointment will be needed?____________________________________________

(continues)

number of grams of solute should equa

arts of 12%,” Alligation calcue checked by

hich is the desirations used to mi

ng the followi

strengtsolutions mayformula:

1 mL89 mL__

dext2

� 13___

he sum



2. How many mL of each of a 20% stock solution and a30% stock solution will a technician need to make 500mL of a 28% solution?____________________________________________

3. An order for 6 liters of 0.9% sodium chloride solution isto be prepared from 23.4% concentrated NaCl solutionand sterile water for injection. How many milliliters ofeach will be used?____________________________________________

4. A technician is to prepare 250 mL of a 40% solutionfrom a 60% stock solution and purified water. Howmany milliliters of each are needed?____________________________________________

(continued)5. A liter of 1/3 NS is to be prepared from 23.4%

concentrated sodium chloride solution and sterilewater for injection. How many milliliters of each are tobe used?____________________________________________

6. Stock solutions of 27% and 31% are available in thepharmacy. How many milliliters of each stock solutionare needed to prepare 2 L of a 29% solution?____________________________________________

7. From two stock solutions, 18% and 42%, you are toprepare 1.5 L of a 34% solution. How many milliliters ofeach of the stock solutions do you need?____________________________________________

T E S T Y O U R K N O W L E D G ET E S T Y O U R K N O W L E D G E

Calculate the following drugs ordered for one dose.

1. Ordered: Xanax 1.5 mg p.o. t.i.d.On hand: Xanax 2 mg tablets scored into fourthsGive: ____________________

2. Ordered: Prilosec 40 mg p.o. t.i.d.On hand: Prilosec 20 mg delayed-release capsulesGive: ____________________

3. Ordered: Clozaril 50 mg p.o. q.d.On hand: Clozaril 25 mg tabletsGive: ____________________

4. Ordered: Ceftin liq 500 mg p.o. b.i.d.On hand: Ceftin suspension 125 mg per 5 mLGive: ____________________

5. Ordered: Zovirax 800 mg p.o. q4hOn hand: Zovirax suspension 200 mg per 5 mLGive: ____________________

6. Ordered: Motrin 600 mg p.o. t.i.d.On hand: Motrin liquid 100 mg / 5 mLGive: ____________________ mL

7. Ordered: Decadron 1.5 mg p.o. q.d.On hand: Decadron 0.75 mg unscored tabletsGive: ____________________

8. Ordered: Isoptin SR 240 mg p.o. q12hOn hand: Isoptin SR 120 mg tabletsGive: ____________________

9. Ordered: penicillin G 400,000 U p.o. q.i.d.On hand: penicillin G 250 mg (400,000 U) tabletsGive: ____________________

10. Ordered: Aspirin grv p.o. q.d.On hand: Aspirin 325 mg tabletsGive: ____________________

11. Ordered: Minipress 2 mg p.o. b.i.d.On hand: Minipress 1 mg capsulesGive: ____________________

12. Ordered: Tegretol 0.2 g p.o. t.i.d.On hand: Tegretol 100 mg chewable tabletsGive: ____________________

13. Ordered: thyroid gr ss p.o. q.i.d.On hand: thyroid 30 mg tabletsGive: ____________________

14. Ordered: Nalfon 300 mg p.o.On hand: Nalfon 600 mg tabletsGive: ____________________

15. Ordered: Elixir of phenobarbital 30 mg p.o. b.i.d.On hand: Elixir of phenobarbital 20 mg per 5 mLGive: ____________________

16. Ordered: Atarax 30 mg p.o. b.i.d.On hand: Atarax syrup 10 mg per 5 mLGive: ____________________

17. Ordered: Vibramycin 100 mg p.o. b.i.d.On hand: Vibramycin 50 mg / 5 mLGive: ____________________

18. Ordered: Inderal 30 mg p.o. q.i.d. p.c.On hand: Inderal 20 mg tabletsGive: ____________________

T E S T Y O U R E S T Y O U R W L E D G EW L E D G EW L E D G E



19. Ordered: Urecholine 50 mg p.o. t.i.d.On hand: Urecholine 25 mg tabletsGive: ____________________

20. Ordered: Halcion 0.25 mg p.o. h.s.On hand: Halcion 0.125 mg tabletsGive: ____________________

See the three medication administration records andaccompanying labels on the following pages forquestions 21 through 35.

Calculate one dose of each of the drugs prescribed.Labels A–O provided on the following pages are thedrugs you have available. Indicate the lettercorresponding to the label you select.

1/5/xx

1/5/xx 1/5 Tegretol 200 mg b.i.d. PO 9 9 9 GP 9 MS

1/5/xx 1/5 Allegra 60 mg b.i.d. PO 9 9 9 GP 9 MS

1/5/xx 1/5 sucralfate1000 mg b.i.d. PO 9 9 MS

1/5/xx 1/5 Naprosyn 0.5 g q.i.d. PO 9 GP

NKA

Patient, Mary Q.

GP G. Pickar, R.N.

1/5/xx

MS M. Smith, R.N.

19

1 GP5 MS9 MS

9 9 GP

(A)(continues)

21.

22.

23.

24.



(B)

1/5/xx

GP1/5/xx 1/5 Synthroid 0.2 mg q.d. PO 9 9

GP1/5/xx 1/5 Diabeta 5 mg q.d. PO 9 9

12 GP MS 1/5/xx 1/5 erythromycin

0.8 g q.12h PO 6 1 2 6 12 6 GP MS

1/5/xx 1/5 Klonopin 500 mcg t.i.d. 9 9 9 9

AldactoneGP MS

1/5/xx 1/5 0.1 q.d.g PO 9 9 9 9

Patient, J ohn Q.

1/5/xx

GP G. Pickar, R.N.

MS M. Smith, R.N.

PO

(continued)

25.

26.

27.

28.

29.



(C)

PRN7 30 GP

1/5/xx 1/5 Percocet 1 tabq.4h p.r.n. headache PO 1130GP

1/5/xx

GP G. Pickar R.N.

MS M. Smith, R.N .

NKA

Doe, Jane Q.

1/5/xx

digoxin 91/5/xx 1/5 0.5 mg q.d.

PO 9 GP potassium chloride 8 9

GP9

1/5/xx 1/540 mEq c iv juice b.i.d. PO 9 9 MS

7 30 430

1/5/xx 1/5 Lopid 0.6 g b.i.d. ac PO 7 30 430 GP MS 9

1/5/xx 1/5 Furosemide 40 mg q.d. PO 9 GP9 9

1/5/xx 1/5 Lopressor 100 mg b.i.d. PO 9 9 GP MS

–

(continues)

30.

31.

32.

33.

34.

35.



(A) (Courtesy of Hoechst Marion Roussel, Inc.)

(B) (Courtesy Roche Laboratories, Inc.)

(C) (Courtesy of Aventis Pharmaceuticals)

(D) (Courtesy of Ciba-Geigy Corporation)

(continued)



(E) (Courtesy of Pharmaceutical Associates, Inc.) (F) (Courtesy of Mylan Pharmaceuticals Inc.)

(G) (Courtesy of Aventis Pharmaceuticals)

(H) (Courtesy of Abbott Laboratories)

(I) (Courtesy of Knoll Pharmaceuticals)(continues)



(J) (Courtesy of Aventis Pharmaceuticals)

(K) (Label reproduced with permission of Pfizer Inc.)

(L) (Reproduced with permission of GlaxoSmithKline)

(M) (Courtesy of Pharmacia Corporation, Peapack, NJ)

(continued)



(N) (Courtesy of Novartis)

(O) (Courtesy of Endo Pharmaceuticals)

Calculate one dose of the medications indicated onthe MAR. Labels A–C provided on the following pageare the drugs available. Indicate the lettercorresponding to the label you select.

(continues)



3/8/xx

3/8/xx

3/8/xx

3/8/xx

9 9 3-8 Inderal 80 mg b.i.d. PO 9 9 GP MS 9 9 3-8

Lasix 20 mg b.i.d. PO 9 9 GP MS 93-8

Slow-K 600 mg q.d. PO 9 GP

GP G. Pickar R.N.

MS M. Smith, R.N.

(A) (Courtesy of Wyeth Pharmaceuticals, Philadelphia, PA)

(B) (Courtesy of Aventis Pharmaceuticals)

(continued)

36.

37.

38.



(C) (Courtesy of Novartis)

CRITICAL THINKING

1. The physician ordered Inderal 120 mg p.o. q.d. Thepharmacy technician supplied 20 mg tablets. The nursedid not think about the reasonable amount that shouldbe taken in a 1-day period and mistook “q.d.” for“q.i.d.,” then calculated the dosage as follows:

120 mg� 4 � 24 tab (incorrect)

20 mgIf the nurse gave the patient 24 tablets of 20 mg pertablet Inderal, how many milligrams will the patient re-ceive over a 24-hour period? Is it the correct dosage?

Desired

Have* Quantity = Amount


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