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## Calculation of Doses

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**Calculation of Doses**Lab 7**defenictions**• Dose: is the quantitative amount administered or taken by a patient for intended medicinal effect. • Single dose, daily dose, total dose, divided doses and dosage regimen**Dose measurment**• In hospital • In home:liquid dosage is usually measured in “household” terms.Teaspoonful = 5 mLTablespoonful = 15 mL • The drops as a unit of measure- the drop used as a measure for small volumes of liquid medications, and doesn’t represent a definite quantity.- the official dropper is calibrated to deliver approximately 20 drops per milliliter.**General dose calculations**• The pharmacist often needs to calculate the size of a dose, the number of doses, or the total quantity of medication to dispense. Number of doses = Total amount Size of dose**Practice problems**• If the dose of a drug is 200 mg, how many doses are contained in 10 g? • How many teaspoonful would be prescribed in each dose of an elixir if 180 mL contained 18 doses? • How many milliliters of liquid medicine would provide a patient with 2 tablespoonfuls twice a day for 8 days? • if a preparation contains 5 g of drug in 500 mL, how many grams are contained in each tablespoonful dose? • How many capsules, each containing a 150 µg dose of a drug may be prepared from 0.12 g of the drug?**Practice problems**• A solution contains 660 mg of sodium fluride per 120 mL and has a dose of 10 drops. If the despensing dropper calibrates 25 drop/mL, how many milligrams of sodium flouride are contained in each dose? • How many milliliters of mixture would provide a patient with a teaspoonful dose to be taken three times a day for 16 days? • How many drops would be prescribed in each dose of a liquid medicine if 15 mL contained 60 doses? The dispensing dropper calibrates 32 drops/mL • If 1 tablespoonful is prescribed as the dose, approximately how many doses will be contained in 1 pint of the medicine?**Practice problems**• A cough mixture contains 48 mg of hydromorphone hydrochloride in 8 fl. Oz. How many milligrams of hydromorphone hydrochloride are in each 2-teaspoonful dose? • if 0.05 g of substance is used in preparing 125 tablets, how many micrograms are represented in each tablet? • How many grams of drug will be needed to prepare 72 dosage forms if each is to contain 30 mg?**Home work**• Pediatric LANOXIN injection containes digoxin, 100 µg/mL. what volume must be administered to provide a dose of 0.04 mg? • RESTASIS ophthalmic emulsion contains 0.5% w/v cyclosporin. If a dose of one drop measures 28 µL, how many µg of cyclosporin present? • If a liquid medicine to be taken three times daily, and if 180 mL are to taken in 4 days, how many tablespoonful should be prescribed for each dose?