Exam 2- Week 5 Flashcards
Risk factors for antibiotic resistance
recent use of antibiotics, age younger than 2 years or older than 65 years, day-care center attendance, exposure to young children, multiple medical comorbidities, recent hospitalization, and immunosuppression
Risk factors for hypersensitivity reaction to PCN
A history of a serious hypersensitivity reaction (e.g., anaphylaxis, serum sickness, exfoliative dermatitis, hemolysis, or other blood dyscrasia) to a penicillin contraindicates the use of any penicillin on account of crossreactivity. Severe, type I allergic reactions to cephalosporins, carbapenems, or beta-lactamase inhibitors may contraindicate use of penicillins.
Risk factors for hypersensitivity reactions to Cephalosporins
Like the penicillins, cephalosporins may produce hypersensitivity reactions in a small percentage of patients. Crosssensitivity with penicillins increases the risk and occurs in 5% to 16% of patients. Cephalosporins are generally not recommended for those who have had a type 1 (immediate, anaphylactic) reaction to any penicillin. Skin testing is not helpful for identifying individuals likely to experience anaphylactic reactions to cephalosporins.
Safest antibiotics in pregnancy
Pregnancy contraindicates several classes of antibiotics, such as tetracyclines and fluoroquinolones, so aminopenicillins (Amoxicillin and Ampicillin) may be used for gravid women, even though another agent is the drug of choice.
Why clavulanate is added to amoxicillin
Because of the increasing beta-lactamase production among gram-negative pathogens and anaerobes, amoxicillin and ampicillin are often combined with beta-lactamase inhibitors, clavulanic acid, and sulbactam, respectively, for enhanced gram-negative and anaerobic activity. As combination products, ampicillin/sulbactam and amoxicillin/ clavulanate have excellent activity against methicillinsusceptible Staphylococcus aureus (MSSA), Streptococcus and Enterococcus species, Moraxella catarrhalis, Haemophilus influenzae, Neisseria meningitidis, Escherichia coli, Klebsiella, Proteus mirabilis, Salmonella,some Shigella species, Pasteurella multocido, Actinomyces, Clostridium, Peptostreptococcus, and Bacteroides fragilis
Appropriate antibiotics for pediatrics
Amoxicillin is the most common drug prescribed to pediatrics because of limited toxicities. It comes in liquid form and tastes good. Is given 2-3 times a day (convenience). The CDC recommends TMP/SMX, amoxicillin/clavulanate, cefixime, cefpoxdoxime, cefprozil, or cephalexin in children 2-24 months
Guidelines related to prophylactic antibiotics prior to a dental appointment
currently recommends therapy only for those with prosthetic heart valves, previous infective endocarditis, certain patients with congenital heart disease, and cardiac transplant patients with valve regurgitation who are undergoing dental procedures that involve manipulation of either gingival tissue or the periapical region of the teeth. Patients with congenital heart disease (CHD) who require prophylaxis include those with unrepaired cyanotic CHD, completely repaired CHD repaired with prosthetic material or device during the first 6 months after repair, and repaired CHD with residual effects at the site of the prosthetic patch or device. Amoxicillin (adults 2 g and children 50 mg/kg orally 1 h before procedure) and ampicillin (adults 2 g and children 50 mg/kg IM or IV within 30 min before procedure) dshould be used as first-line therapy. Penicillin-allergic patients should use cephalosporins (cefazolin, ceftriaxone, cephalexin), clindamycin, or the newer macrolides (azithromycin, clarithromycin) for prophylaxis.
Antibiotics that target the cell wall
Gram positive organisms: Beta-lactams (PCN, cephalosporins, carbapenems, monobactam), Bacitracin, vancomycin, daptomycin.
Gram negative: polymixins
Antibiotics that block protein synthesis
Rifampin ahminoglycosides macrolides tetracyclines chloramphenicol clinda
Antibiotics that target DNA replication
Sulfonomides
Quinolones
Flagyl
Trimethoprim
Beta-lactams
Core is four member ring called beta lactam ring. Inhibit penicillin binding proteins (PBPs). Some are beta lactamase sensitive.
PCNs, cephalosporins, carbapenems, monobactams
Penicillins
Beta-lactam, targets cell wall.
Natural: bactericidal. active against some gram positive, a few gram negative, some anaerobic, and some apirochetes. Ex: pen G & V.
Extended spectrum: more active against gram-negative. Ex: piperacillin
Aminopenicillins: similar to natural except also cover gram-beg rods. Ex: Ampicillin and Amox
PCN-Beta lactamase inhibitor combinations
Addition of inhibitor neutralizes many of the B-lactamases a that otherwise inactivate aminopenicillins
First generation cephalosporins
Beta-lactam, targets cell wall
Best gram-positive coverage among all cephalosporins.
Ex: celhalexin, cefazolin, cefadroxil
Second-generation cephalosporins
Beta-lactamase, targets cell wall
Same activity against gram-positive cocci as 1st gen. Adds activity against aerobic gram-negative organisms
Ceclor, ceftin, cefzil, lorabid
