Parenteral Dosage of Drugs Chapter 11

Calculation of Drug Dosage: Parenteral

Calculation of Drug Dosage: Parenteral Order Cleocin 150 mg IM every 12 hours Available Cleocin (clindamycin phosphate) 300 mg per 2 mL

Calculation of Drug Dosage: Parenteral Step 1. Convert No conversion is necessary.

Calculation of Drug Dosage: Parenteral Step 2. Think You want to give less than 2 mL Actually, you want to give 150 mg, which is of 300 mg and of 2 mL, or 1 mL Calculate to double-check your estimate.

Calculation of Drug Dosage: Parenteral Step 3. Calculate

Calculation of Drug Dosage: Parenteral Given intramuscularly every 12 hours Select a 3 mL syringe Measure 1 mL of Cleocin 300 mg per 2 mL

Ratio-Proportion Method: Parenteral with Conversion Order: Robinul 150 mcg IM stat Supply: Robinul 0.2 mg per mL

Ratio-Proportion Method: Parenteral with Conversion Step 1. Convert Equivalent:

Ratio-Proportion Method: Parenteral with Conversion Step 2. Think Give less than 1 mL but more than 0.5 mL Don’t be fooled into thinking 0.2 mg is less than 150 mcg 0.2 mg is more than 150 mcg 0.2 mg = 200 mcg

Ratio-Proportion Method: Parenteral with Conversion Step 3. Calculate

Ratio-Proportion Method: Parenteral with Conversion Given intramuscularly immediately Select a 1 mL syringe Measure 0.75 mL Robinul 0.2 mg per mL You may have to change needles, as this is an IM injection.

Guidelines for Syringe Selection Standard doses more than 1 mL Round to tenths and measure in a 3 mL syringe 3 mL syringe is calibrated to 0.1 mL increments 1.53 mL is rounded to 1.5 mL Drawn up in a 3 mL syringe

Guidelines for Syringe Selection Small (less than 1 mL), critical care, or children’s doses Round to hundredths and measure in 1 mL syringe 1mL syringe is calibrated in 0.01 increments 0.257 mL is rounded to 0.26 mL Drawn up in a 1 mL syringe

Guidelines for Syringe Selection Amounts of 0.5 –1 mL calculated in tenths Can be accurately measured in either a 1 mL or 3 mL syringe

Insulin Label Concentration Manufacturer Brand Name Storage Species Type Generic Name Expiration Date

Combination Insulin Dosage 40 units NPH Units-100 insulin 12 units Regular Units -100 insulin Total insulin dosage = 52 units

Preparing Combination Insulin Dosage 2. Inject 10 units of air. Inject 30 units of air.

Preparing Combination Insulin Dosage 3. Withdraw 10 units regular. 4. Withdraw 30 units NPH for a total of 40 units.

Insulin Sliding Scale Order Humulin R Regular units-100 insulin subcut based on glucose reading at 1600

Insulin Sliding Scale Insulin Dose Glucose Reading* No coverage Glucose less than 160 2 units 160–220 4 units 221–280 6 units 281–340 8 units 341–400 * Glucose is greater than 400: Hold insulin; call MD stat.