NR565 Week 5 Study Guide New 2023
PCN Spectrum of Coverage
Combination with beta-lactamase inhibitors to broaden their spectrum: clavulanate,
... [Show More] sulbactam, tazobactam
PCN Pharmacodynamics
Inhibits the biosynthesis of peptidoglycan bacterial cell wall (bacterial cell wall synthesis inhibitors).
PCN Pharmacokinetics
Several are unstable in acid: dicloxacillin and amoxicillin. Well-absorbed from GI tract. Bound to proteins w/good distribution to most tissues. Small amount is metabolized, most are excreted as unchanged drug in the urine. Probenecid prolongs the half-life and increases risk for toxicity
PCN Pharmacotherapeutics
Severe, type I allergic reactions to cephalosporins, carbapenems, or beta-lactamase inhibitors may contraindicate use of penicillins. Although historically cross-sensitivity between penicillins and these other classes was thought to be much higher, recent data suggest that the rate is closer to 1%. Patients with a history of allergy to other substances (e.g., atopic skin conditions) should also use these drugs with caution.
PCN Clinical Indications & Dosing
Used for gram-negative urinary and gastrointestinal (GI) pathogens: E. coli, Proteus mirabilis, Salmonella, some Shigella species, and Enterococcus faecalis Gram-negative respiratory pathogens: Moraxella catarrhalis (and Haemophilus influenza type B) Acute Bronchitis, URI, chronic bronchitis, otitis media, sinusitis, pharyngitis, UTI, Sexually transmitted infections, skin and tissue infections, pneumonia, H. Pylori, lyme disease, bacterial endocarditis, Group B Strep. Dosing Adults PO 250-500mg q8hrs or 875mg q12hr, Children over 3months 25-50mg/kg/day in divided doses, Children high dose 80-90mg/kg/day divided into 2 divided doses. Commonly prescribed for infections seen in primary care. Amoxicillin is first-line therapy for otitis media (AOM) and sinusitis. PCN is used for streptococcal pharyngitis. Amoxicillin/clavulante is first-line therapy for infection following bites, including human
PCN ADRs
May cause serious immediate allergic reactions. Reactions occur within 2 to 30 minutes of administration. Rash: maculopapular rash occurs 9% of time that is not allergic in origin, appears 7 to 10 days into treatment. GI: diarrhea, N/V, addition of claulante increases risk of diarrhea. Fungal overgrowth. C. difficile colitis. Most are pregnancy Category B
PCN Monitoring
1. symptom relief 2. diarrhea (C. difficile) 3. Renal function (if prolonged therapy) [Show Less]