Antimicrobials Part 2

Antimicrobials Part 2 Bacteriostatic Inhibitors of Protein Synthesis: suppress growth, don’t kill Tetracyclines: “clyclines”; Tetracycline; Demeclocycline; Doxycycline; Minocycline What are they: Broad-spectrum antibiotics; Inhibit protein synthesis by inhibiting binding transfer RNA to messenger RNA; Increasing bacterial resistance has emerged Uses: Treatment of infectious disease (Rocky Mountain spotted fever); Treatment of acne; Peptic ulcer disease; Periodontal disease; Rheumatoid arthritis; Chlamydia, Mycoplasma pneumoniae; Lyme disease; Anthrax; Helicobacter pylori Absorption: AVOID Calcium supplementsform chelates with Ca, Fe, Mg, Zn, milk products, iron supplements, magnesium-containing laxatives, and most antacids; TAKE WITH FOOD Adverse effects Gastrointestinal irritation: DoxyclyclineN without food Effects on bone and teeth: STAIN TEETH, don’t give to pregnant patients Superinfection: C. Difdiarrhea Hepatotoxicity: fatty infiltration of the liver with IV Renal toxicity: eliminated in urineAccumulate in pts with kidney disease Photosensitivity: wear sunscreen Summary of major precautions: Tetracycline and demeclocycline are eliminated primarily in urine; they accumulate in patients with kidney disease; Tetracyclines can cause discoloration of deciduous and permanent teeth; Diarrhea may indicate a potentially life-threatening suprainfection of the bowel; High-dose IV therapy has been associated with severe liver damage Drug and food interaction: Absorption of tetracyclines is decreased if drug is given with: Milk products, Calcium supplements, Iron supplements, Magnesium-containing laxatives, Most antacids Macrolides “mycins” Erythromycin: Broad-spectrum antibiotic; Usually bacteriostatic but can be bactericidal; Used if patient is allergic to penicillin; Active against most gram-positive and some gram-negative bacteria Mechanism of action (MOA): Inhibition of protein synthesis 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 Drug interactions: Metabolized through CYP3A4, theophylline, carbamazepine, warfarin, verapamil, dilitiazem, HIV inhibitors Adverse effects: Gastrointestinal: N/Vgive with foodincreased absorption QT prolongation and sudden cardiac death: don’t give with ketaconazole Superinfections, thrombophlebitis, transient hearing loss Azithromycin [Zithromax] and Clarithromycin: Prolonged QT interval Clindamycin [Cleocin]: Inhibits protein synthesis; Can promote severe Clostridium difficile – associated diarrhea (CDAD) (can be fatal)  BBW; Active against most ANAEROBIC bacteria