72 Pharma euti al c al ulations
a n SWERS TO “c a SE In POIn T” a n d PRa c TIc E PROb l EMS Case in Point 4.1
(a) Since aa. means “of each,” 10 mg lisinopril and 10 mg hydrochlorothiazide are needed for each capsule. And since D .T.D . means “give of such doses,” 30 cap- sules are to be prepared. T hus,
10 mg lisinopril × 30 (capsules) = 300 mg lisinopril and
10 mg hydrochlorothiazide × 30 (capsules) = 300 mg hydrochlorothiazide are needed to fill the prescription.
(b) Since q.s. ad means “a sufficient quantity to make,” the total in each capsule is 300 mg. T he amount of lactose per capsule would equal 300 mg less the quantity of the other ingredients (10 mg + 10 mg + 40 mg), or 240 mg. T hus,
240 mg lactose/capsule × 30 (capsules) = 7200 mg = 7.2 g lactose.
(c) Take one (1) capsule in the morning before breakfast.
4 • interpretat on of Prescr pt ons and Med cat on Orders 73 (c) Apply morning and night as
needed for pain.
(d) Instill 4 drops into the right ear morning and night.
(e) Take 1 teaspoonful in water every 4 or 5 hours as needed for pain.
(f) Apply ointment to the left eye as needed.
(g) Take 1 capsule with water at bed- time. Do not repeat.
(h) Instill 5 drops into each ear three times a day as needed.
(i) Place 1 tablet under the tongue, repeat if needed.
(j) Instill 2 drops into each eye of the newborn.
(k) Dilute with an equal volume of water and use as gargle every 5 hours.
(l) Take 2 capsules 1 hour prior to departure, then 1 capsule after 12 hours.
(m) Take 1 tablet as needed for short- ness of breath.
(n) Take 1 tablet every morning for high blood pressure.
(o) Take 2 tablets every 6 hours around the clock for urinary tract infection.
(p) Take 2 teaspoonfuls four times a day after meals and at bedtime.
(q) Take 1 tablespoonful before meals three times a day.
(r) Add crushed tablet to pet’s food once a day.
3. (a) AMBIEN 10 mg by mouth at every bedtime for 5 days
(b) 1000 mL of 5% dextrose in water every 8 hours intravenously with 20 milliequivalents of potassium chloride added to every third bottle
(c) Administer 10 mg of prochlor- perazine intramuscularly every 3 hours, if there is need, for nau- sea and vomiting.
(d) O ne teaspoonful of minocy- cline hydrochloride suspen- sion by mouth four times a day.
Discontinue after 5 days.
(e) 10 mg of propranolol hydro- chloride by mouth three times a day before meals and at bedtime (f) 40 units of N PH 100-unit
insulin subcutaneously every day in the morning
(g) 250 mg of cefamandole nafate intramuscularly every 12 hours (h) 15 milliequivalents of potas- sium chloride by mouth twice a day after meals
(i) 1 mg of vincristine sulfate per square meter of patient’s body surface area
(j) Administer 30 mg of fluraz- epam at bedtime as needed for sleep.
(k) Administer 20 milliequiva- lents of potassium chloride per liter in D 5W (5% dex- trose in water) at the rate of 84 milliliters per hour.
(l) Administer 2.5 grams per kilogram of body weight per day of amino acids in total parenteral nutrition.
(m) Start epoetin alfa (PROCRIT ) immediately at 150 units per kilogram of body weight sub- cutaneously and then three times a week for 3 to 4 weeks.
(n) Methotrexate tablets, 2.5 mg each, to be taken three times a day 1 day a week
(o) H ydrochlorothiazide tablets, 12.5 mg, to be taken once each day in the morning
4. (a) 50 days (b) yes
5. (a) 40 tablets.
6. (a) correct.
7. calls for tablets but label indi- cates capsules.
Sig: “in the morning” has been added, which may be correct if that is the prescriber’s usual directive.
Refill “5” times is incorrect; the original filling of a prescription does not count as a refill.
74 Pharma euti al c al ulations
calls for drug name/strength on label; an omission.
It should be noted that after filling the prescription, the pharmacist would have added a prescription number, which would also appear on the label.
8. T he words “all of the medicine”
have been added and the numbers enhanced; this clarifies the direc- tions and thus is positive. 250 mL should be 250 mg.
T he prescription number should appear on the label.
9. Patient’s name is incorrect. T he active drug name only on the label is proper for a compounded pre- scription. T he other ingredients are “pharmaceutic.”
It should be noted that after filling the prescription, the pharmacist would have added a prescription number, which would also appear on the label.
10. (1) “Q ID” means four times a day (2) D rug name is incorrect.
(3) Correct 11. Correct label.
12. Ritonavir: 600 mg twice a day orally for 7 days.
T heophylline: 3 mg per kilogram of body weight every 8 hours for 7 days.
13. 10 milli-international units per milliliter.
14. 6 million international units per square meter of body surface area three times a week.
15. (Take) 20 mg of simvastatin every evening.
16. (T he drug combination of) lopina- vir, 400 mg, and ritonavir, 100 mg, taken twice a day, plus efavirenz, 600 mg, taken once every day.
17. (a) 100 mg metoclopramide H Cl/mL
(b) 0.8 mL nasal spray 18. 41 days
AUTHORS’ EXTRA POINT A
d RUG n a MES
As stated in this chapter, drug substances may be prescribed by their nonproprietary (generic) name or by their brand (trademark) name. The designation of nonproprietary names is based on nomenclature reflecting a drug’s chemical structure and/or pharmacologic activity. In the United States, each nonproprietary name is assigned by the United States Adopted Names (USAN) Council, which is cosponsored by the American Medical Association, the United States Pharmacopeial Convention, and the American Pharmacists Association.
To harmonize the program, the USAN Council works in conjunction with the federal Food and Drug Administration (FDA) as well as the World Health Organization (WHO) and the International Nonproprietary Name (INN) Expert Committee. Together with the British Approved Names (BANs) and the Japanese Approved Names (JANs), the USP Dictionary of USAN and International Drug Names database contains more than 8,400 nonproprietary drug name entries.a
Many of the same drug substances are approved for marketing and available internationally. In the United States, this approval is within the authority of the federal Food and Drug Administration.b There are many multinational pharmaceutical companies who engage in the worldwide development and marketing of pharmaceutical products. The brand names assigned to the same nonproprietary-named drug often differ country to country. The referenced International Drug Name Database contains more than 40,000 medica- tion names from 185 countries and is presented in multiple languages.c
The nonproprietary names used in the calculation problems in this text are universal; however, the brand names by their very nature are not.
ahttp://library.dialog.com/bluesheets/html/bl0464.html
bRegulatory approval is within the purview of each country. In Canada, regulatory authority resides with Health Canada’s Therapeutic Products Directorate (TPD). Within the European Union (EU), the 28 member countries depend collectively upon the European Medicines Evaluation Agency (EMEA) for drug approvals and regulation. A list of drug regulatory agencies world- wide may be found at http://www.regulatoryone.com/p/websites-of-regulatory-agencies.html
chttp://www.drugs.com/international/
4 • interpretat on of Prescr pt ons and Med cat on Orders 75
AUTHORS’ EXTRA POINT B
El Ec TROn Ic PRESc RIPTIOn S
aThe overall integrated system of electronic health information includes electronic health records (EHRs), computerized physician order entry (CPOE), and electronic prescriptions (e-prescriptions). The system allows health care providers to electronically insert and access patients’ vital medical information.
In the processing of electronic prescriptions, a complex network of pharmacies, payers, pharmacy benefit managers (PBMs), physicians, hospitals, health information exchanges (HIEs), and electronic health record systems (EHRs) must be connected in real time to assure patient eligibility, formulary data, and clinical require- ments. As is shown in Figures 4.10 and 4.11, this information connectivity is facilitated by health information networks (Surescripts in the example), which notify providers of authorization status and requirements.
Pha rmacy Be nefit Manage r
(PBM)
Pha rma cy S upe rscripts
e Rx - How it Works
Eligibility, Formula ry,
Me dica tion His tory
Eligibility, Formula ry, Me dica tion His tory/Fill S tatus Pa tient Inquiry
Informa tion
Pres cription Da ta
Ma inta ins a n index of e nrolle d pha rma cie s
a nd route s pre scriptions to the
de sire d loca tion Ma inta ins a ma s te r
pa tie nt index a nd route s inquire s to ma tche d PBMs
P re s cription Fill S tatus
Pa tient Demogra phics / P re s cription
athenaClinicals
FIGURE 4.1 0 • Information connectivity in the processing and authorization of an e-prescription. (Image pro- vided through the courtesy of athenahealth, Inc. [Images © athenahealth, Inc., used with permission.] Additional information from http://surescripts.com/.)
FIGURE 4.1 1 • An example of an e-prescription being ordered during a patient’s visit with medical reference information embedded (Epocrates) to provide real-time decision clinical support. (Image provided through the courtesy of athenahealth, Inc. [Images © athenahealth, Inc., used with permission.] Additional information from
76 Pharma euti al c al ulations
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