Parenteral Dosage of Drugs Chapter 11 MAT 119

Parenteral Routes Route of administration other than gastrointestinal Intramuscular (IM) Subcutaneous (subcut) Intradermal (ID) Intravenous (IV)

Z-Track Injection Z-Track

Parenteral Routes Used to describe drugs given by any route other than oral, sublingual, topical, or rectal Generally associated with drugs administered by a needle The term “parenteral” means by injection.

Parenteral Routes Benefits: Good for drugs that are poorly absorbed, rapid response, patient is uncooperative, unconscious, etc. Disadvantage: Expensive, require skilled personnel, is an invasive technique

Parenteral Routes All routes have limitations: Limited to solutions, suspensions, and emulsions Must be sterile (bacteria-free) pH must be maintained May require buffers Volume limited (IM, ID, Subcut)

Parenteral Medications Most parenteral medications are prepared in liquid form and packaged in single, or multi-dose vials Ampules or prefilled syringes

Parenteral dosages Round amount to be administered to tenths if the amount is greater than 1 mL and measure it in a 3 mL syringe Order: Administer 1.33 mL = 1.3 mL

Parenteral dosages Measure amounts less than 1 mL rounded to hundredths and all amounts less than 0.5 mL in a 1 mL syringe. Order: Administer 0.65 mL

Parenteral dosages Amounts of 0.5 mL to 1 mL calculated in tenths can be accurately measured in either a 1 mL or a 3 mL syringe (usually use 3 mL for IM > 0.5 mL) Order: Administer 0.6 mL

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

Three Steps Step 1: Convert Step 2: Think Step 3: Calculate All units of measurement must be in same system and all units must be in same size Step 2: Think Estimate logical amount Step 3: Calculate Dosage on hand = Dosage desired Amount on hand X amount desired

Cleocin 150 mg IM q.12h Available: Cleocin (clindamycin phosphate) 300 mg per 2 mL Step 1: Convert No conversion is necessary Step 2: Think You want to give less than 2 mL Actually, you want to give 150 mg, which is 1/2 of 300 mg and 1/2 of 2 mL, or 1 mL Calculate to double-check your estimate

Cleocin 150 mg IM q.12h Available: Cleocin (clindamycin phosphate) 300 mg per 2 mL Step 3: Calculate 300 mg = 150 mg 2 mL X Give 1 mL Cleocin IM every 12 hours

Calculation of Drug Dosage: Parenteral Order: Robinul 100 mcg IM stat Supply: Robinul 0.2 mg per mL Convert: Equivalent: 1 mg = 1,000 mcg 0.2 mg = 0.200 = 200 mcg Think: Give less than 1 mL about 1/2 Don’t be fooled into thinking 0.2 mg is less than 100 mcg 0.2 mg is more than 100 mcg 0.2 mg = 200 mcg

continued Order: Robinul 100 mcg IM stat Supply: Robinul 0.2 mg per mL Step 3: Calculate:

continued Give IM Select a 1 mL syringe Measure 0.5 mL Robinul 0.2 mg per mL You have to change needles, as this is an IM injection. Change to 1-1 1/2” needle

Insulin Label Find: Supply dosage/concentration Total volume Brand name Type Manufacturer Label alerts Generic Name Species

Insulin Supply dosage of insulin is 100 units per mL Abbreviated on label as U-100 Syringe must also be U-100 Accuracy is critical Nurses must understand and correctly interpret insulin order and label The correct syringe must be selected

Insulin Syringes Standard U-100 50 Lo-Dose U-100 30 Lo-Dose U-100

Interpreting the Insulin Order Brand name, including the species and action time. Rapid-acting (Regular) Intermediate-acting (NPH) Long-acting (Lantus) Supply dosage (concentration and number of units to be given) Route of administration and time or frequency Regular insulin only type to be given IV

Examples Humulin R Regular U-100 insulin 14 units subcut stat Novolin N NPH U-100 insulin 24 units subcut 1/2 hour ā breakfast

Types of Insulin

Other Delivery Systems Insulin Pump

Inhaled Insulin

Insulin Sliding Scale No coverage Glucose less than 160 2 units 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 greater than 400: Hold insulin, call MD stat Order: Humulin R Regular U-100 insulin subcut a.c. based on sliding scale p. 229 #26-30

Insulin: Avoiding Errors Check dosage with two nurses When combination dosages are prepared, two nurses must verify each step of the process.