Chapter 10 Oral Dosage of Drugs © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Oral Medications Oral medications come in a variety of forms Tablets Capsules Liquids © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Tablets and Capsules Supplied in strengths or dosages in which they are commonly prescribed Only scored tablets are intended to be divided © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Three-Step Approach to Dosage Calculations Step 1: Convert Ensure that all measurements are in the same system and same size unit; if not, convert before proceeding Step 2: Think Estimate what is a reasonable amount of the drug to administer © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Three-Step Approach to Dosage Calculations (Continued) Step 3: Calculate Apply the formula © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Three-Step Approach to Dosage Calculations (Continued) D represents desired dosage H represents dosage on hand per a quantity Both H and Q represent the supply dosage found on the label of the drug available © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Three-Step Approach to Dosage Calculations (Continued) Example Order: Lopressor 100 mg Supply: Lopressor 50 mg/tablet Convert No conversion necessary © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Three-Step Approach to Dosage Calculations (Continued) Think You want to give twice the equivalent of each tablet, or 2 tablets per dose Calculate © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Example Example Convert Think Order: Flagyl 0.75 g po tid Supply: Flagyl 500 mg/tablet Convert Conversion is needed 1 g = 1,000 mg, so 0.750 g = 750 mg Think How many tablets per dose should be administered? © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Example (Continued) Calculate © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Caution The maximum number of tablets or capsules for a single dose is usually three Stop, think, and recheck your calculation if a single dose requires more Question all orders that exceed that amount © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Converting to Same System Preferable to convert to smaller unit Usually eliminates decimal or fraction, keeping calculation in whole numbers © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Apothecary and Household Measurements Convert to metric equivalents Metric system is predominant system of measurement for drugs © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Converting to Different System Order: Codeine sulfate gr ¾ p.o. q.4h p.r.n., pain Supply: Codeine sulfate 30 mg per tablet What do you notice? Different system Needs to be converted © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Converting to Different System (Continued) Step 1: Convert Convert to equivalent units: convert gr to mg Approximate equivalent: gr i = 60 mg © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Converting to Different System (Continued) Conversion factor is 60 Larger to Smaller (×) Order: Codeine gr ¾ = 45 mg Supply: Codeine 30 mg tablets © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Converting to Different System (Continued) Step 2: Think You estimate that you want to give more than one tablet but less than two tablets © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Converting to Different System (Continued) Step 3: Calculate Give every 4 hours as needed for pain © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Math Tip When solving dosage problems for drugs supplied in tablets or capsules Q = one tablet or capsule Q (quantity) is always one, because the supply dosage is per one tablet or capsule © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Remember Do not always rely on a formula Always estimate what is a reasonable amount of the drug to be administered This helps to identify if the dosages calculated are reasonable and sound © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Remember © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.