Module_4

Determine the value for x : 1. Available: Lisinopril 10 mg tablets, Order: 20 mg 10 mg : 1 tab = 20 mg : x tab Determine the value for x : 10 mg : 1 tab = 20 mg : x tab 10x = (1)20 10/10 x = 20/10 x = 2 tabs Proof checking: 10 x 2 = 20 x1 = 20 (product of extremes) = (product of means) 1) Order: dilaudid 2 000 mcg IV q4h prn pain • Available: dilaudid 4 mg per 1mL • How many mL will you administer per dose? Desired dose ( D ) Have onhand ( H ) ×Quantity ( Q ) = Unknown ( x ) 2 mg 4 mg × 1 mL = x mL x = 0.5 mL 2) Order: lisinopril 10 mg PO daily • Available: lisinopril 2.5 mg tablets • How many tablets will you administer per dose? Desired dose ( D ) Have onhand ( H ) ×Quantity ( Q ) = Unknown ( x ) 10 mg 2.5 mg × 1 tab = xtab x = 4 tab 3) Order: dimenhydrinate 25 mg PO Q6H PRN Available: dimenhydrinate 50 mg tablets • How many tablets will you administer per dose? Desired dose ( D ) Have onhand ( H ) ×Quantity ( Q ) = Unknown ( x ) 25 50 × 1 tab = x tab x = 0.5 tab

Metres (m) is base Larger = kilo (km) Smaller = milli/cent etc. (mm, cm ) * Same for Litres (L) Please review RULES for Metric System pg. 73 Box 5-2 Q: What is the difference between the following examples? Why might the cause a problem .52 mL & 0.52 mL 2.5 mL & 2.50 mL

Calculate the total volume consumed for breakfast in mL • Indicates medications administered by any route other than through the GI system. • Commonly refers to routes via needle • IM, SUBCUT, ID and IV • Generally, these act more quickly than oral medications because they are absorbed more rapidly into the bloodstream • Medications for parenteral use may be packaged in various forms, including ampules, vials, mix-o-vials, cartridges, and prefilled syringe Syringes and Needle Safety • Classified as Luer-Lok or non–Luer-Lok (Luer-Slip) • Both are disposable and designed for one-time use. • Luer-Lok syringes require special needles that are twisted onto the tip and lock themselves in place, which prevents inadvertent removal of the needle. • Non–Luer-Lok syringes require needles that slip onto the tip • Needles come in various lengths and diameters. The nurse chooses the needle according to the patient’s size, the type of tissue being injected into, and the viscosity of the medication to be injected. Some syringes also come with a needle attached that cannot be detached from the syringe. Syringes: Hypodermic, Tuberculin, and Insulin • Hypodermic syringes come in a variety of sizes, from 0.5 mL to 60+ mL • 3-mL syringe is used most often for the administration of medication doses that are between 1 and 3 mL • Small hypodermics, decimal numbers are used to express dosages (e.g., 1.2 mL, 0.3 mL). Small hypodermics also have fractions on them • Large hypodermics (5 - 12 mL) - Used to measure whole numbers of mL as opposed to smaller units. Are calibrated in increments of fifths of a millilitre (0.2 mL), with the whole numbers indicated by long lines. • Syringes that are 20 mL and larger are calibrated in whole millilitre increments and can have other measurements, such as ounces, on them. Tuberculin versus Insulin Syringe A tuberculin syringe is a narrow syringe that has a capacity of 0.5 mL or 1 mL. • The volume in mL and is calibrated in hundredths (0.01 mL) and tenths (0.1 mL) of a millilitre. • The markings on the syringe are closer together to indicate how small the calibration is Insulin syringes marked with “U-100” are calibrated for administration of U-100 insulin only. • Insulin is measured in units and should be administered only with an insulin syringe. • The insulin syringe and the tuberculin syringe are different. Confusion of the two can cause a medication error. • Dosages in millilitres should be expressed as decimals even when the syringe is marked with fractions.

Types of Syringes—Insulin Insulin is a high-alert medication. Always check insulin dosages with another nurse before administration. Reading Syringes a. What is the total volume of the vial? (2 mL) b. What is the dosage strength? (25 mg per mL) c. What is the route of administration? IM/IV d. If 12.5 mg was ordered, how much would you draw up? What syringe would you choose? (2 mL; 3 or 5 mL syringe) a. What is the total volume of the vial? (10 mL) b. What is the dosage strength? (25 mg per mL) c. If 50 mg was ordered, how many mL would need to be administered? (2 mL) d. What is the best syringe to use for this dose? (3 or 5 mL)

• Can be calculated by using the same rules and methods used to calculate oral dosages. • The ratio and proportion method, the formula method, and the dimensional analysis method have been presented in earlier chapters. We will practice some applications. The following guidelines will help you calculate a dosage that is logical, reasonable, and accurate. • Convert if necessary and calculate using one of the methods presented (see next slide) • For injectable medications, there are guidelines on the amount of medication that can be administered in a single site. • If amount exceeds the amount that can be administered in a single site, give in two injections to different sites. • Consider the condition of the patient, the site selected, and the absorption and consistency of the medication o A patient may not be able to tolerate the maximum dosage volume. Guidelines on the amount of medication that can be administered in a single site Intramuscular • The maximum volume to administer in a single intramuscular site is as follows: • Average-sized adult = 3 mL (for deltoid muscle, 1 mL) • Children ages 6 to 12 years = 2 mL • Children ages 0 to 5 years = 1 mL • It should be noted that intramuscular injections are less common in the clinical setting than in the past. Subcutaneous • The maximum volume to administer in a single subcutaneous site for an adult is 1 mL. Intravenous Injectable solutions that are added to an intravenous solution may have a volume of more than 5 mL Guidelines for Calculating Parenteral Dosages When calculating and preparing an injectable dosage, keep the following in mind: • 3-mL syringe - calibrated in 0.1-mL increments. o Round millilitres to the nearest tenth when measuring using a 3-mL syringe; never round to a whole unit.  Example: 1.75 mL = 1.8 mL • 1-mL (tuberculin syringe) is calibrated in 0.01 mL increments. If the math calculation does not work out evenly to the hundredths place, then the division is carried to the thousandths place and rounded to the hundredths place.

o Example: 0.876 mL = 0.88 mL. o It is recommended that dosages less than 0.5 mL be measured with a 1-mL syringe. • Large syringes (5, 6, 10, and 12 mL) are calibrated in 0.2-mL increments. o Dosages are also expressed to the nearest tenth. • Dosages should be measured in mL, and the answer should be labelled accordingly. • Insulin is measured and administered in units Practice Problems Regardless of what method you use to calculate, apply the following steps: 1. Check to make sure the desired dosage and dosage on hand are in the same system and unit of measurement. 2. Think critically about what the answer should logically be before you calculate. 3. Consider the type of syringe to use. • The cardinal rule should always be that any dosage given must be able to be measured accurately in the syringe you are using. 4. Solve using the ratio and proportion method, the formula method, or the dimensional analysis method. Order Gentamicin 75 mg IM q8h Available: Gentamicin labelled 40 mg per mL Note: No conversion is necessary. Think: The dosage ordered is going to be more than 1 mL but less than 2 mL. Set up the problem and solve Solution Using Ratio and Proportion • Solution Using the Formula Method Solution Using Dimensional Analysis Order (Test Yourself) Ceftriaxone 0.25 g IM stat q12h Available: Ceftriaxone labelled 350 mg per 1 mL A conversion is necessary. Conversion factor: 1 000 mg = 1 g. Convert what is ordered to what is available: 0.25 g = 250 mg.

• Additionally, antibiotics may be bacteriostatic or bactericidal in terms of how it targets the bacteria. • Finally, the mechanism of action is also considered in the selection of an antibiotic. • Common abbreviation for your note taking – Abx Gram Cultures A culture is a test performed to examine different body substances for the presence of bacteria or fungus • collected from a patient’s blood, urine, feces, sputum, wound etc. • Take sample first! o Antibiotic administration prior to a culture can result in a delayed identification of the organism and complicate the patient’s recovery • Culture is monitored for signs of organism growth • Aid in the diagnosis of the infectious pathogen • Performed to select an effective antibiotic to treat the microorganism. o If the organism shows resistance to the antibiotics used in the test, those antibiotics will not provide effective treatment for the patient’s infection. Sometimes a patient may begin antibiotic treatment for an infection, but will be switched to a different, more effective antibiotic based on the culture and sensitivity results Spectrum of Activity • Broad-spectrum o Targets a wide variety of bacterial pathogens, including both gram positive and gram negative o Used for polymicrobial infections (a mixed infection with multiple bacterial species) o Used as prophylactic prevention of infections with surgery/invasive procedures o May used when a narrow-spectrum drug fails because of development of drug resistance by the target pathogen • Narrow-spectrum o Only specific subsets of bacterial pathogens o Only gram positive OR only gram negative • If the pathogen causing infection has been identified in a culture and sensitivity test, it is best to use a narrow-spectrum antimicrobial and minimize collateral damage to the normal microbacteria Gram Positive • Streptococcus & Staphylococcus • "Strep" - most common cause of bacterial pharyngitis (strep throat); various skin infections that can be relatively mild (e.g., impetigo) or life threatening (e.g., necrotizing fasciitis, also known as flesh-eating disease, strep-pneumonia • "Staph” - skin infections that produce boils, carbuncles, cellulitis, or impetigo. o Many strains of S. aureus have developed resistance to antibiotics. Some antibiotic-resistant strains are designated as methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) .

Gram Negative • Bacteria often grow between aerobic and anaerobic areas (such as in the intestines). Some gram-negative bacteria cause severe, sometimes life-threatening disease • N. gonorrhoeae STI gonorrhea, and N. meningitides bacterial meningitis, E scherichia coli (E. Coli) (UTI), H. pylori) Risks of Antibiotics • Broad-spectrum - they will also target a broad spectrum of the normal microbacteria and can cause diarrhea • Increase the risk of a superinfection • Many patients stop taking antimicrobials once their symptoms dissipate and they feel better. o If a 10-day course of treatment is prescribed, many patients only take the drug for 5 or 6 days, unaware of the negative consequences of not completing the full course of treatment • A shorter course of treatment - fails to kill the target organisms , assists in creating drug-resistant variants within the body. • Abx are overprescribed, used when not needed (ear infection, flu/virus) o Patients often demand antibiotics for diseases that do not require them, like viral colds and ear infections Antibiotics: Mechanism of Action • How and where the drug will ultimately target the bacteria • Decision about whether to use a bacteriostatic or bactericidal drug often depends on the type of infection and the overall immune status of the patient • Bactericidal: kill their target bacteria. • Bacteriostatic: cause bacteria to stop reproducing; however, they may not ultimately kill the bacteria • Many types of antibiotics available – many different bacterial pathogens! • Summary of how various antibiotics affect the cell wall, the plasma membrane, the ribosomes, the metabolic pathways, or DNA synthesis of bacteria Antibiotics: Mechanisms of Action • The cell wall, which is impacted by: • β-lactams, such as penicillins, cephalosporins, monobactams, carbapenems; • Glycopeptides, such as vancomycin; • Bacitracin. • The plasma membrane, which is impacted by: • Polymyxins, such as polymyxin B, colistin; • Lipopeptides, such as daptomycin. • Ribosomes, including: • 30S subunit, which is affected by aminoglycosides, tetracyclines;

Assessment, implementation, evaluation Assessment: What drug are you giving and why? Implementation: • Anticipate any additional interventions associated with the medications (i.e., gastrointestinal upset (GI) such as nausea, diarrhea) o "Take with food", "Take on an empty stomach" • Hypersensitivity/allergic reactions are always a potential adverse reaction o Immune responses that are exaggerated or inappropriate to an antigen and can range from itching to anaphylaxis. o Anaphylaxis is a medical emergency that can cause life-threatening respiratory failure. Early signs of anaphylaxis include, but are not limited to, hives and itching, the feeling of a swollen tongue or throat, shortness of breath, dizziness, and low blood pressure. Evaluation • Assess for absence of or decreasing signs of infection, • Document these findings to reflect the patient’s trended response • Monitor for C. diff Types of Antibiotics Penicillin: Penicillins are prescribed to treat a variety of infectious processes such as Streptococcal infections, Pneumococcal infections, and Staphylococcal infections. Cephalosporins: Cephalosporins are used to treat skin and skin-structure infections, bone infections, genitourinary infections, otitis media, and community-acquired respiratory tract infections. Carbepenems: Carbapenems are useful for treating life-threatening, multidrug-resistant infections due to their broad spectrum of activity Monobactams: Monobactams are narrow-spectrum antibacterial medications that are used primarily to treat gram-negative bacteria such as Pseudomonas aeruginosa. Sulfonamides: Sulfonamides are used to treat urinary tract infections, otitis media, acute exacerbations of chronic bronchitis, and travelers’ diarrhea. Fluoroquinolones: may be used to treat pneumonia or complicated skin or urinary tract infections Macrolides: Macrolides are often used for respiratory infections, otitis media, pelvic inflammatory infections, and Chlamydia. Aminoglycosides : Streptomycin is used for streptococcal endocarditis and a second line treatment for tuberculosis Tetracycline : Tetracycline medications are useful for the treatment of many gram-positive and gram-negative infectious processes yet are limited due to the significance of side effects experienced by many clients. Key Takeaway • Noting that antibiotics differ in variety and mechanism of action (MOA) • Chosen based on spectrum and how it affects the bacteria • Important to note if there’s resistance • The nurse should always know WHY the patient is receiving an antimicrobial to evaluate if the patient is improving or deteriorating