Chapter 6 calculation of Oral Medications – Solids and Liquids
2. Quantity /strength of drug on hand 3. solid or liquid form of supply drug
D = doctor’s order H = on hand or have S = supply form (e.g., tablets, mL) A = Answer
Rules Formula Method Desire x Supply = Amount Have Ratio Method Supply: Have :: x : Desire Proportion Method Supply
Proportions expressed as two fractions 1 tablet equal to 50 mg 1tablet 50 mg X tablets 100 mg 1tablet = x tablets
50 mg 100 mg Solve for “X” x = 2 tablets
Tablets - how many tablets to administer
ORAL SOLIDS Example Order: Coreg 6.25 mg po bid Supply: read the label (12.5 mg per tablet; 100 tablets) Desire: 6.25 mg Have: 12.5 mg Supply: 12. 5 mg tablets
(D/H) x S = (6.25 mg /12.5 mg) * 1 tablet = 0.5 tablet Ratio Method: S:H :: x:D
Clearing Decimals: add 0s appropriately to have same number of places (to the right of decimal) 0.5
Order: Lanoxin 0.125 mg po every day Supply: read the label (100 tablets, 250 mcg (0.25 mg), scored tablets) (Desire/Have ) x Supply = Amount
(0.125 mg/0.250 mg) x 1 tablet = ½ tablet
Order: amoxicillin 1g po q6h Supply: 1 capsule equals 500 mg (1000 mg/500 mg ) x 1 cap = 2 capsules Order: Synthroid 75 mcg po every day
Supply: read label (75 mcg; tablet form) (75 mcg/75 mcg) x 1 tablet Order: ZyPrexa 7.5 mg po every day Supply: read the label (60 tablets, each tablet is 5 mg) (7.5mg/5mg) x 1 tablet = 1 ½ tablet Order: Lamictal 200 mg po every day Supply: read the label (100 tablets, each tablet 100 mg) (200 mg/100 mg) x 1 tablet = 2 tablets Ratio S : H :: x : D 1tablet : 100 mg :: x : 200mg Order: furosemide 60 mg po every day Supply: read the label (40mg/tablet; 100 tablets) 1 tablet: 40 mg :: x : 60 mg (60mg/40 mg) x 1 tablet = 1 ½ tablet Order: Keflex 1 g po q6h
Supply: capsules labeled 500 mg (1000mg/500mg) x 1 capsule = 2 capsules Special types of oral solid orders: drug with a number of active ingredients are ordered by number to be administered Vitamin B complex caplets 1 po every day Aggrenox 25 mg/200 mg capsules 1 capsule po bid DO NOT ASSUME THAT THE TRADE NAME IMPLIES JUST ONE ACTIVE INGREDIENT ORAL LIQUIDS Review: D: doctor’s order H: on hand/have S: supply FORM (e.g., tablet, mL) A: amount to give patient Formula: D/H X S = x Ratio Method: S:H :: X:D
Proportion Method: S/H = x/D Oral liquids: aqueous solution, elix, sol, syr, gel, magma
Measure: medicine drops, medicine cups, needless syringes Examples Order: azithromycin oral susp 400 mg po every day x 4 days CHECK LABEL FOR SUPPLY ON HAND This drug had to be mixed with water 400 mg x 5mL = 10 mL 200 mg Order: digoxin elixir 500 mcg x 1 dose Supply: read label Equivalent: 500 mcg = 0.5 mg 0.500 mg x 2.5 mL = 10 mL 0.125 mg EQUIVALENCY Order: furosemide 34 mg po every day Supply: read label-> 10 mg per mL 60mL 34mg x 1mL = 3.4 mL (use calibrated dropper) 10mg
Order: digoxin 0.375 mg po every day Supply: read label
0.375 mg x 5 mL = 7.5 mL 0.25 mg (use syringe first) Order: amoxicillin oral suspension 500 mg po q8h Supply: read label 125
500 mg x 5 mL = 20 mL 125 mg Special Types of Oral Liquid Orders Some liquids (OTC preps, multivitamins) -> ordered in amount to be poured Order: Robitussin syrup 2 tsp q4h prn po Supply: liquid labeled Robitussin syrup THOU SHALT NOT LIE! THOU SHALT NOT COVER UP!
THOU SHALT WRITE DOWN EVERYTHING ON THE CHART
Changes in Depressive Symptoms and Social Functioning in theSequenced Treatment Alternatives to Relieve Depression StudyJohn W. Denninger, MD, PhD,* Adrienne O. van Nieuwenhuizen, MSc,* Stephen R. Wisniewski, PhD,ÞJames F. Luther, MSc,Þ Madhukar H. Trivedi, MD,þ A. John Rush, MD,§ Jackie K. Gollan, PhD,||Diego A. Pizzagalli, PhD,¶ and Maurizio Fava, MD*antidepressants, social functioning
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