NUR 613 Exam 2 Study Guide Antimicrobials

NUR 613 Exam 2 Study Guide Antimicrobials Understand the adverse effects of combining drugs such as fluoroquinolones and theophylline. How would you manage patients taking both of these drugs concurrently? Page 929 Cimetidine, fluoroquinolone antibiotics (eg. ciprofloxacin), and other drugs can elevate theophylline levels. When combined with these drugs, theophylline should be used in reduced dosages Review the different generations of cephalosporins and understand the indications for use and mechanism of action. (this can be found in Module 4 powerpoint) Page 1026 Cephalosporins • Most widely used group of antibiotics • Beta-lactam antibiotics • Similar to penicillin structure • Broad spectrum • Bactericidal • Resistant to beta-lactamases • Usually given parenterally • Low toxicity • Mechanism of action • Bind to penicillin-binding proteins (PBPs), disrupt cell wall synthesis, and cause cell lysis • Most effective against cells undergoing active growth and division Resistance • Beta-lactamases (cephalosporinases) • First-generation (ex. cephalexin) destroyed • Second-generation (ex. cefoxitin) less sensitive to destruction • Third- (ex. cefotaxime), fourth- (cefepime), and fifth-generation (ex. ceftaroline) agents highly resistant. Therapeutic Uses of Cephalosporins • 1st generation: Widely used for prophylaxis against infection in surgical patients; rarely used for active infections (cephalexin) • 2nd generation: Rarely used for active infections (cefoxitin) o• 3rd generation (cefotaxime) • Preferred therapy for several infections • Highly active against gram-negative organisms • Able to penetrate to cerebrospinal fluid (CSF) • 4th generation (cefepime) • Commonly used to treat health care‒ and hospital-associated pneumonias, including those caused by the resistant organism Pseudomonas • 5th generation (ceftaroline) • Infections associated with MRSA Know the major side effect(s) of Rifampin and what to monitor when treating patients with this medication. Pg 1078 Most common adverse effect is hepatitis; monitor LFTs; discoloration of body fluids (harmless red-orange colored urine, sweat, saliva, and tears. Consult ophthalmologist for contact lens staining), GI disturbances, Caution should be exercised when giving drug to alcoholics or pts who have preexisting liver disorders; At High doses- SOB, hemolytic anemia, shock and renal failBe familiar with drugs in the Macrolide family. (covered in Module 4 review) Pg 1040; Pg 1048 (Erythromycin, Clarithromycin, Azithromycin) Macrolides (Erythromycin) • Broad-spectrum antibiotic, similar to penicillin • Mechanism of action (MOA): Inhibition of protein synthesis • Usually bacteriostatic but can be bactericidal • Used if patient is allergic to penicillin • Active against most gram-positive and some gram-negative bacteria • Therapeutic uses: Whooping cough, acute diphtheria, Corynebacterium diphtheriae, chlamydial infections, M. pneumoniae, group A Streptococcus pyogenes • May be used as an alternative to penicillin G in patients with penicillin allergy • Adverse effects • Gastrointestinal • QT prolongation and sudden cardiac death when combined with inhibitors of CYP3A4 • Superinfections, thrombophlebitis, transient hearing loss • Erythromycin may increase the half-lives and plasma levels of theophylline, carbamazepine, and warfarin • Verapamil, diltiazem, and HIV drugs can increase erythromycin levels Interferon alfa (treats Hepatitis C or B) frequently causes neuropsychiatric effects— especially depression. Suicidal ideation and suicide have occurred. The risk of depression is increased by large doses and prolonged treatment. Page 1116 pg. 1112 Depression can be treated with antidepressant (paroxetine) but if it continues tx will need to be stopped. Most common SE is flu-like syndrome but usually decreases over time. MAO – multiple effects on viral replication cycle, after binding to receptors on host cell membranes the drug blocks viral entry into cells, synthesis of viral messenger RNA and viral proteins, and viral assembly and release. Lab values to monitor in patients on gentamicin and how to monitor them. (covered in Module 4 powerpoint and review) Page Measure trough levels of drug to monitor risk of ototoxicity; Measure BUN and creatinine to monitor for nephrotoxicity. Discontinue at FIRST sign of ototoxicity (tinnitus, persistent headache), cochlear damage is irreversible. Samples for peak levels ● Taken 30 minutes after giving an IM injection OR ● After completing a 30-minute IV infusion ● Not indicated for once daily dosing → high peak levels are guaranteed ● Therapeutic level = 4-10 Sampling for trough levels depends on the dosing schedule ● Divided doses: Take sample just before the next dose ● Once-daily doses: Draw a single sample 1 hour before the next dose; value should be very low ‒ preferably close to zero ● Recommended level = 1-2 Probenecid (promotes renal uric acid excretion) delays renal excretion of some cephalosporins and can thereby prolong their effects. This is the same interaction that occurs between probenecid and penicillins Page 894 Also delays excretion of indomethacin and sulfonamides, dosages may need reductions. (pg. 1021, 1027) Understand the adverse effects of isoniazid (Treatment and prophylaxis of TB) and how to monitor those effects. Page 1076 ● Monitor for signs of hepatotoxicity (especially in ETOH users and older patients), AST levels ● Peripheral neuropathy: tingling, numbness, burning or pain in hands or feet, notify if these occur; can be reversed with small daily doses of B6 (pyridoxine) ● Optic neuritis, anemia What are the contraindications of tetracycline administration? (Covered in Module 4 review and Module 4 powerpoint) Page 1037 Contraindicated in pregnant women and in children younger than 8 yrs. old and should be avoided in women who are breastfeeding. Binds to calcium - stains teeth yellow or brown Used with great caution in patients with renal impairment Tetracyclines increases risk of superinfection more so than other antibiotics Know the difference between mild, moderate and severe C. Diff and how to manage the different types. Page Initial, mild or moderate: Leukocytosis with a WBC 15000 cells/mcL or lower and SCr less than 1.5 baseline, treat with metronidazole 500 mg PO TID for 10-14 days Initial, severe: : Leukocytosis with a WBC 15000 cells/mcL or higher or SCr 1.5 baseline or higher, treat with Vanco 125 mg PO QID 10-14 days Initial, severe complicated: Leukocytosis with a WBC 15000 cells/mcL or higher or SCr 1.5 baseline or higher, either one PLUS hypotension/shock, ileus, megacolon. Tx with Metronidiazole 500 mg IV q 8 PLUS Vanco 500 mg PO/NG QID for 10-14 days. If complete ileus, add vanco retention enema. First reoccurrence, same as initial episode tx Second recurrence: Vanco PO tapered: 125 mg QID 10-14 days then 125 mg twice daily for 7 days, then 125 mg once daily for 7 days, then 125 mg every 2-3 days for 2-8 weeks Understand the recommendations, contraindications, and different types of flu vaccine, I would encourage reading the entire section on the flu vaccine on page 1118 of your Lehne Textbook. Inactivated influenza vaccine (IM or ID) Live, attenuated influenza vaccine (IN) Protection begins 1-2 wks after vaccination and lasts 6mths or longer Inactived flu vaccine- Small risk of GBS; (LAIV)-GBS, anaphylaxis, Bells Palsy People with acute febrile illness should defer until symptoms abate; Minor illness (common cold) with or without fever, do not preclude vaccination S/S 5-17: runny nose, nasal congestion, cough, headache, vomiting, muscle aches, fever. 18- 49: runny nose, headache, sore throat, cough. Hypersensitivity to Eggs; just hives-may take vaccine; angioedema and respiratory distress- should be referred to allergist for risk assessment before receiving vaccination All people age 6mths and older should be vaccinated; The inactivated vaccine should be given to especially young children under 5, those 18 or older on long term aspirin, pregnant women, people age 65 and older, morbidly obese, nursing homes/long term care facilities, American Indians/Alaska natives, immunocompromised or use immunosuppressant drugs, spinal cord injury, asthma, anemia, diabetes, heart/kidney/lung disease, neurologic disorders(epilepsy, cerebral palsy)- NO LIVE VACCINES to pregnant women. NO VACCINE AT ALL TO: severe allergy to eggs, severe reaction to influenza vaccine, GBP When to vaccinate? Oct/Nov Method of Action of Bactericidal drugs (covered in Module 4 review and powerpoint) Bactericidal-drugs that are directly lethal to bacteria at clinically achievable concentrations Drugs that inhibit bacterial cell wall synthesis or activate enzymes that disrupt the cell wall (Penicillin, cephalosporins) weaken cell wall and thereby promote bacterial lysis and death Drugs that cause lethal inhibition of bacterial protein synthesis (aminoglycosides) are the only drugs in this group. Itraconazole inhibits CYP3A4 (the 3A4 isoenzyme of cytochrome P450) and thus can increase levels of many other drugs Review (Table 92–3). The most important are cisapride, pimozide, dofetilide, and quinidine. When present at high levels, these drugs can cause potentially fatal ventricular dysrhythmias. Accordingly, concurrent use with itraconazole is contraindicated. Other drugs of concern include cyclosporine, digoxin, warfarin, and sulfonylurea-type oral hypoglycemics. In patients taking cyclosporine or digoxin, levels of these drugs should be monitored; in patients taking warfarin, prothrombin time should be monitored; and in patients taking sulfaonylureas, blood glucose levels should be monitored Page 1095 Adverse effects of Amphotericin B and what to monitor in patients taking this medication? (covered in Module 4 review and powerpoint) Page Amphotericin B Adverse effects Infusion reactions (Fever, Nausea, Headache, Phlebitis) Nephrotoxicity • If total dose exceeds 4 g, residual impairment is likely • Damage can be minimized by infusing 1 L of saline on treatment days • Monitor Serum Creatinine level every 3-4 days • Hypokalemia results from damage to kidneys, Potassium supplements may be needed Hematologic Effects • Can cause bone marrow suppression, anemia • Monitor hematocrit Acyclovir mechanism of action and indication in clinical practice Acyclovir MOA: inhibits viral replication by suppressing synthesis of viral DNA. To exert antiviral effects, acyclovir must first undergo activation (pg 1106) Drugs for HSV (herpes simplex) and VSV (varicella zoster virus): Acyclovir (Zovirax) ● agent of first choice for most infections caused by HSV and VSV ● administered topically, orally, and intravenously ● active only against members of the herpes virus family (this includes Herpes Simplex Virus (HSV), Varicella Zoster Virus (VSV), and cytomegalovirus (CMV). ● Adverse Effects ● Intravenous therapy ○ Phlebitis ● Reversible Nephrotoxicity- indicated by Cr and BUN; injury increased by dehydration and use of other nephrotoxic drugs ● Neurotoxicity - occurs in renal impairment patients ● Oral therapy- Gastrointestinal (N/V/D), headache, and vertigo ● Topical therapy - Stinging sensations Chapter 57 Diabetes Mellitus (about 11 questions) Medication Treatment Options for DM: focus on the ones listed here and understand these items for each: · Mechanisms of Action · Pharmacokinetics · Contraindications · Treatment based on schedule/meals/lifestyle issues Insulin Generic Name Trade Name MOA Pharmacokinetics Route Insulin lispro Humalog Rapid acting analog of regular insulin; acts faster than regular insulin and has a shorter duration of action. Onset -- 15-30 min Peak -- 0.5 - 2.5 hours subQ or insulin pump Can be given Structure is identical to natural insulin; 2 amino acids switched --because of this switch, molecules of insulin lispro aggregate less than molecules of regular insulin = rapid acting Can be administered immediately before eating, or even after eating. Duration -- 3-6 hours IV -- very expensive Insulin aspart Novolog Rapid acting analog of human insulin. Very similar to insulin lispro. One amino acid -- proline Injections should be made 5-10 min before meals Onset -- 10-20 min Peak-- 1-3 hours Duration -- 1-1.5 hours subQ or subQ infusion or pre- filled pens Can be given IV -- very expensive Insulin glulisine Apidra Synthetic analog of natural human insulin with a rapid onset Should be administered close to the time of eating Onset -- 10-15 min Peak -- 1-1.5 hours Duration -- 3-5 hours Pre-filled pens, subQ injection or continuous subQ infusion Can be given IV, very expensive Regular Insulin Humulin R, Novolin R Unmodified human insulin. Short duration, slower acting insulin. Can be injected before meals to control postprandial hyperglycemia and infused subQ to provide basal glycemic control Following subQ injection, molecules of regular insulin form small aggregates (dimers and hexamers) at the injection site, as a result, absorption is delayed. Supplied in clear solution U-100 or Onset -- 30-60 min Peak -- 1-5 hours Duration -- 6-10 hours subQ injection subQ infusion IM oral inhalation Off label for IV -- only the U- 100 formulation should be used; less expensive U-500 -- reserved for extreme insulin resistance; NEVER IV because of concentration NPH Insulin Humulin N, Novolin N Prepared by conjugating regular insulin with protamine. The presence of protamine decreases the solubility of NPH insulin and thus delays absorption Cannot be administered at meal time Injected 2-3x daily to provide glycemic control between meals during the night Only one suitable for mixing with short-acting insulins Cloudy mixture that must be agitated before administration Onset -- 60-120 min Peak -- 6-14 hours Duration -- 16-24 hours subQ only pre-filled pins Insulin glargine Lantus Modified human insulin with prolonged duration of action (up to 24 hours). Differs from natural human insulin by 4 amino acids → low solubility at physiologic pH → when injected subQ, forms microprecipitates that slowly dissolve, and thereby release insulin glargine in small amounts over an extended time. Achieves blood levels that are relatively steady Clear solution; NOT mixed; never IV Onset -- 70 min Peak -- none Duration -- 18-24 hours subQ Insulin detemir Levemir Human insulin analog with slow onset and dose-dependent duration of action. Low doses = 12 hours; higher doses = 20-24 hours Used to provide basal glycemic control, not given before meals Onset -- 60-120 min Peak -- 12-24 hours Duration -- Varies subQ Clear, colorless solution; NOT IV; NOT MIXED Differs from natural insulin -- one amino acid removed --14 carbon fatty acid chain has been attached to the B chain Adhere strongly to each other and absorption is delayed Fatty acid chain causes insulin detemir to bind strongly with plasma albumin and distribution to target sites is delayed even further · When is it indicated: DM (1 and 2), IV for ketoacidosis, gestational diabetes, hyperkalemia, aids in the diagnosis of GH deficiency · Complications of insulin treatment: Hypoglycemia (70=conscious fast acting sugars such as oral glucose tablet/OJ/sugar cubes/non-diet soda; unconscious give IV glucose or parenteral glucagon), lipohypertrophy, allergic reactions, hypokalemia, (drug interactions with hypoglycemic agents/hyperglycemic agents/beta-adrenergic blocking agents) · Excessive administration can cause fatal results from what type of electrolyte problem (hint besides hypoglycemia): hypokalemia