Miscellaneous Calculations - Pharmaceutical Calculations

1. Miscellaneous
Calculations

2. INTERNATIONAL
SYSTEM OF UNITS

3. INTERPRETATION
OF
PRESCRIPTIONS
AND
MEDICATION
ORDERS
PRESCRIPTION

4. INTERPRETATION
OF
PRESCRIPTIONS
AND
MEDICATION
ORDERS
PRESCRIPTION

5. INTERPRETATION
OF
PRESCRIPTIONS
AND
MEDICATION
ORDERS
PEDIATRIC
PRESCRIPTION

6. INTERPRETATION
OF
PRESCRIPTIONS
AND
MEDICATION
ORDERS
COMPOUNDING
PRESCRIPTION

7. INTERPRETATION
OF
PRESCRIPTIONS
AND
MEDICATION
ORDERS
MEDICATION
ORDER

8. SELECTED ABBREVIATIONS, ACRONYMS, AND SYMBOLS
USED IN PRESCRIPTIONS AND MEDICATION ORDERS

9. SELECTED ABBREVIATIONS, ACRONYMS, AND SYMBOLS
USED IN PRESCRIPTIONS AND MEDICATION ORDERS

10. SELECTED ABBREVIATIONS, ACRONYMS, AND SYMBOLS
USED IN PRESCRIPTIONS AND MEDICATION ORDERS

11. SELECTED ABBREVIATIONS, ACRONYMS, AND SYMBOLS
USED IN PRESCRIPTIONS AND MEDICATION ORDERS

12. SELECTED ABBREVIATIONS, ACRONYMS, AND SYMBOLS
USED IN PRESCRIPTIONS AND MEDICATION ORDERS

13. SELECTED ABBREVIATIONS, ACRONYMS, AND SYMBOLS
USED IN PRESCRIPTIONS AND MEDICATION ORDERS

14. INTERPRETATION OF PRESCRIPTIONS & MEDICATION ORDERS
• Examples of prescription directions to the pharmacist:
(a)M. ft. ung.
(b) Ft. sup. no xii
(c) M. ft. cap. d.t.d. no. xxiv
• Examples of prescription directions to the patient:
(a) Caps. i. q.i.d. p.c. et h.s.
(b) gtt. ii rt.eye every a.m.
(c) tab. ii stat tab. 1 q. 6 h. 7 d.

15. SELECTED CLINICAL
CALCULATIONS
• An intravenous infusion contained 20,000 units of
heparin sodium in 1000 mL of D5W. The rate of infusion
was set at 1600 units per hour for a 160-lb. patient.
Calculate:
(a) the concentration of heparin sodium in the infusion,
in units/mL;
(b) the length of time the infusion would run, in hours;
(c) the dose of heparin sodium administered to the
patient, on a unit/kg/minute basis.

16. SELECTED CLINICAL
CALCULATIONS
• The recommended dose of dalteparin sodium
(FRAGMIN) for patients undergoing hip
replacement surgery is 2500 international units (IU)
within 2 hours before surgery, 2500 IU 4 to 8 hours
after surgery, and 5000 IU daily 5 to 10 days, starting
on the postoperative day.
How many milliliters from a vial containing
10,000 IU/mL should be administered (a) before
surgery, (b) after surgery, and (c) the day
following surgery?

17. INTRAVENOUS INFUSIONS & PARENTERAL ADMIXTURES
• How many grams each of dextrose and sodium chloride are used
to prepare a 250-mL bag of D51⁄2NS for intravenous infusion?
• A physician orders midazolam hydrochloride (VERSED) 2 mg IV
Stat. A pharmacist delivers a vial containing midazolam
hydrochloride 5 mg/mL. How many milliliters should be
administered?
• A medication order for a patient weighing 154 lb. calls for 0.25 mg
of amphotericin B per kilogram of body weight to be added to
500 mL of 5% dextrose injection. If the amphotericin B is to be
obtained from a constituted injection that contains 50 mg/10 mL,
how many milliliters should be added to the dextrose injection?
• A medication order for a child weighing 44 lb. calls for polymyxin B
sulfate to be administered by the intravenous drip method in a
dosage of 7500 units/kg of body weight in 500 mL of 5% dextrose
injection. Using a vial containing 500,000 units of polymyxin B
sulfate and 10 ml of sodium chloride injection as the solvent,
explain how you would obtain the polymyxin B sulfate needed in
preparing the infusion.

18. ALLIGATION ALTERNATE
• How many milliliters of 50% w/v dextrose solution
and how many milliliters of 5% w/v dextrose solution
are required to prepare 4500 mL of a 10% w/v
solution?
• In what proportion should 20% benzocaine ointment
be mixed with an ointment base to produce a 2.5%
benzocaine ointment?

19. Constitution of Dry
Powders for Oral Use
• The label for a dry powder package of cefprozil (CEFZIL) for oral
suspension directs the pharmacist to add 72 mL of purified water
to prepare 100 mL of suspension. If the package contains 2.5 g
of cefprozil, how many milligrams of the drug would be
contained in each teaspoonful dose of the constituted
suspension?
• Label instructions for an ampicillin product call for the addition
of 78 mL of water to make 100 mL of constituted suspension
such that each 5 mL contains 125 mg of ampicillin. Calculate
the volume of dry powder in the product and the total content
of ampicillin.
• Using the product in the previous example, if a physician desires
an ampicillin concentration of 100 mg/5 mL (rather than 125
mg/5 mL), how many milliliters of water should be added to the
dry powder?