Exam 2 Study Guide_M5 & 4 VC & Discussion Board Q&A

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