Quick Review Chapter 10 Oral dosages of drugs Tablets, capsules Liquid medications and volume 3 step approach to dosage calculations Scoring of medication, fewest number of pills, sustained release, enteric coated

Step 1 Are the measurements in the same system? convert Are the measurements in the same system? Are the units in the same size? Math tip: more practical to covert from larger to smaller units (g to mg)

Step 2 Does the quantity or volume make sense? estimate Does the quantity or volume make sense? What is the reasonable amount to be administered?

Step 3 calculate Pills or capsules the amount on hand will always equal 1 Liquid meds depend on the concentration or supply dosage

Parenteral Dosage of Drugs Chapter 11 Parenteral Dosage of Drugs

Parenteral Route of administration other than gastrointestinal Intramuscular (IM) Subcutaneous (SC) Intradermal (ID) IV Intramuscular is an injection directly into the muscle Subcutaneuous means an injection given into the sq tissue Intravenous is an injection given directly into a vein when a pt has an iv, meds are typically ordered in that form Intradermal is an injection given just underneath the skin (allergy test or tb) has the longest absorption time of all routes there fore used for sensitivity tests

Parenteral Most medications prepared in liquid or solution form and packaged in: Dosage vials Ampules Prefilled syringes Injectable drugs measured in syringes

Injectable Solutions IM maximum dose volume for injection: RULE: Average 150 lb adult = 3 mL Maximum for deltoid site = 2 mL Children age 6 to 12 years = 2 mL Children birth to age 5 years = 1 mL Need to take into consideration pt’s condition when selecting volume and needle size.

Solving Parenteral Dosage Problems Apply same three steps used when calculating oral dosages Convert All units of measurement must be in same system and all units must be in same size Think Estimate logical amount Calculate Set up ratio between dosage on hand and desired dosage

Rules Parenteral dosages Amounts greater than 1 mL…round amount to be administered (X) to tenths Measure in 3 mL syringe Amounts less than 1 mL… round the amount to be administered (X) to hundredths all amounts less than 0.5 mL Measure in a 1 mL syringe Amounts of 0.5 mL to 1 mL calculated in tenths can be accurately measured in either 1 mL or 3 mL syringe Talk about examples on page 267-268

3 mL syringe 2.33 rounded to 2.3 mL

1 mL syringe 0.297 round to 0.3 mL

Example One Order: Cleocin 150 mg IM every 12 h Available: Cleocin 300 mg per 2 mL How many mL are needed for each dose? Prompt class to use 3 step approach to solve

Example One Convert Think Calculate No conversion necessary Estimate giving less than 2 mL Actually want to give 150 mg, which is half of 300 mg and half of 2 mL, or 1 mL Calculate to double-check estimate Calculate

Example One Calculate Cross-multiply Simplify Ask class what would be best syringe

Example One 1 mL should be given intramuscularly every 12 hours Select 3 mL syringe Measure 1 mL of Cleocin from 300 mg per 2 mL (dosage supply) from vial

Example Two Order: Robinul 150 mcg IM stat Available: Robinul 0.2 mg per mL How many mL are needed for each dose? Have class use 3 step method…. Convert and think…

Example Two Convert Think Equivalent: 1 mg = 1,000 mcg Give less than 1 mL but more than 0.5 mL Avoid being fooled into thinking 0.2 mg is less than 150 mcg 0.2 mg is more than 150 mcg 0.2 mg = 200 mcg Have class calculate

Example Two Calculate Cross-multiply Simplify Ask class what syringe they would choose

Example Two 0.75 mL of Robinul is to be given immediately Select 1 mL syringe Measure 0.75 mL of Robinul 0.2 mg per mL (dosage supply) May need to change needles Due to IM injection REVIEW SET 24 1-6 in class p. 280

High-Alert Parenteral Medications Drugs that bear a heightened risk of causing significant patient harm when they are used in error Examples: Heparin* Insulin* Heparin and Insulin have been identified as 2 of the highest risk medications for severe error potential…in dosage calculations, fatal dosing errors, reading drug labels incorrectly, making mistakes in filling ADC’s; ALSO -both used daily in nursing -both use units (potential for mix up) -units are usually small…use of incorrect syringe -may have multidose vials which may look alike -both given subcut and/or IV

Heparin Anticoagulant New label content and design per USP Strength per total volume as primary expression Followed by strength per mL ALWAYS identify the concentration of supply as well as total volume in container. Prevents formation of blood clots…aka thrombosis…used as prophylaxis (pre and post surgery) Page 292 look at labels page 292

Insulin Accuracy in insulin preparation/administration is critical! Inaccuracy can be life threatening! Essential to read/understand label, interpret order, choose correct insulin syringe! Is a hormone made in the pancreas necessary for metabolism of glucose, proteins, and fats. Patients who are deficient in insulin are required to take insulin by daily injection.

Insulin Common supply dosage of insulin is 100 units per mL Abbreviated on label as U-100 Syringe must also be U-100 Is a hormone made in the pancreas necessary for metabolism of glucose, proteins, and fats. Patients who are deficient in insulin are required to take insulin by daily injection. Insulin is a ready to use solution measured in UNITS © Cengage Learning 2016

Insulin Syringes 100 unit dose 100 units/1 mL 50 unit low-dose 50 units/0.5 mL 30 unit low-dose 30 units/0.3 mL

Insulin Also available as 500 units per mL Used only in special circumstances for diabetic pt’s marked insulin resistance (daily requirement of > 200 units) Use extreme caution when administering Accidental overdose may result in irreversible insulin shock or death U-500 insulin syringe not available Use 1 mL syringe

Insulin Critical to be accurate Nurses must understand and correctly interpret insulin order Identify components of label Must select correct syringe Page 296 to look at label identification

Interpretation of insulin label Brand and generic names Supply dosage or concentration Other instructions Have class look at labels page 296-297

Remember: Two nurses check Insulin at 4 steps: Physician order Insulin selected Calculated dose Dose drawn up

Insulin Action and Times Onset Peak Duration Rapid-acting (lispro, aspart, glulisine) 5 to 15 minutes 45 to 75 minutes 2 to 4 hours Short-acting (regular) 30 minutes 5 to 8 hours Intermediate-acting (NPH) 2 hours 6 to 10 hours 18 to 24 hours Long-acting (detemir, glargine) – Up to 24 hours Talk about Regular and NPH insulin first (page 2970 Insulin is categorized by ACTION TIMES, with Onset, Peak, and Duration times Page 297 looks at the different types of insulin labels and their ACTION TIMES

Insulin An insulin analog is the newest type of insulin that has been chemically modified to act faster or slower than the type of insulin naturally made by the body. Most people with type 1 diabetes should use insulin analogs to reduce hypoglycemia risk (American Diabetes Association, 2013) The rapid acting and long acting analogs

Premixed Combination Insulin Combination of short-acting and intermediate-acting insulin mixed in one vial Read label carefully to understand each type of insulin and concentration included in combination Two types that are often mixed: Regular (R) NPH (N) Pre-mixed are used as a CONVENIENCE for pt’s who are in a treatment plan using these 2 insulins which reduce the # of injections daily. LOOK at labels page 298 11-3

Interpreting the Insulin Order Order must include: Brand name, generic name, and action time Supply dosage (concentration) and number of units Route of administration and time frequency Example: Novolin N NPH U-100 insulin 24 units, Subcut, 30 minutes before breakfast daily Must be written CLEARLY and contain SPECIFIC information to negate errors! (write on board from book, page 299) Other examples: Humulin R regular U-100 insulin 14 units subcut stat Page 319 questions 5-10

Insulin Sliding Scale Purpose: Order: To cover or correct elevation in patient’s blood glucose level Order: Humulin R U-100 insulin Subcut based on glucose reading at 1600 (Orders are based on algorithms in facility) This is a special insulin order needed to “cover” a pt’s increasing blood sugar that is not yet regulated. Because a short onset of action is needed, a rapid acting insulin or short acting insulin will be used.

Insulin Correctional Scale Insulin Dose Glucose Reading* No coverage Glucose less than 160 2 units 160 to 220 4 units 221 to 280 6 units 281 to 340 8 units 341 to 400 If glucose reading is 250, how many units of Humulin R U-100 insulin should be administered? * If greater than 400, hold insulin and call MD stat Page 325 questions 36-40

Rules for Measuring Insulin in an Insulin Syringe Measure U-100 insulin in U-100 insulin syringe only Use U-100 insulin syringes only to measure U-100 insulin Measure U-500 insulin in 1 mL syringe Two nurses must check insulin dosage before administration to patient

Measuring U-500 Insulin in a 1 mL Syringe Order: Humulin R U-500 regular insulin 280 units Subcut stat Available: Humulin R U-500 regular insulin How many mL are needed? Calculating Insulin using 3 step approach: Have class do 1,2,3

Measuring U-500 Insulin in a 1 mL Syringe Convert Recall that U-500 equals 500 units per mL Think There are 500 units in 1 mL 280 units is slightly more than half Estimate giving a little more than 0.5 mL Calculate to determine exact amount

Measuring U-500 Insulin in a 1 mL Syringe Calculate Cross-multiply Ask class what syringe they will choose Simplify

Measuring U-500 Insulin in a 1 mL Syringe 0.56 mL must be given immediately Draw up 0.56 mL of Humulin R U-500 regular insulin in 1 mL syringe

Combination Insulin Dosing Two types of insulin prescribed to be administered at same time Usually rapid- or short-acting and intermediate-acting insulin ordered for same time If compatible, both insulins can be drawn up into same syringe Check manufacturer recommendation Long-acting insulins cannot be mixed in syringe with another insulin E.g., detemir, glargine

Combination Insulin Dosing Example order: Novolin N NPH U-100 insulin 40 units and Novolin R U-100 insulin 12 units Subcut before breakfast daily First determine total number of units needed and choose correct insulin syringe 40 + 12 = total of 52 units Need standard U-100 insulin syringe

Preparing Combination Insulin Dose Follow clear-to-cloudy rule Draw up clear insulin (regular) first Then draw up cloudy (NPH) insulin Roll vial of cloudy insulin in hands to mix before beginning procedure If you withdraw too much NPH, you must discard the entire medication and start over Never combine long-acting insulin with other insulin solutions, as this may be life threatening

Procedure for Combining Two Insulins in the Same Syringe Draw back and inject 40 units of air into NPH insulin vial Withdraw needle Draw back and inject 12 units of air into regular insulin vial Leave needle in vial Page 307

Procedure for Combining Two Insulins in the Same Syringe Turn vial of U-100 regular insulin upside down and draw out insulin to 12-unit mark Insert needle into NPH insulin vial and withdraw insulin to 52-unit mark Page 307 shows example of combining insulins in the syringes

Insulin: Avoiding Errors Check dosage with two nurses ** When combination dosages prepared, two nurses must verify each step of the process ** have class name each step of the process: Physician order Insulin selected Calculated dose Dose drawn up REVIEW SET 25: BEGIN WITH QUESTION