DMU Lecture Final: IV Antibiotics & Antimicrobial Stewardship (PDF)

„ There are multiple dosing strategies for IV antibiotics including intermittent infusion, extended infusion, and continuous infusion o These are usually optimizing depending on the pharmacokinetics and pharmacodynamics of the drug: Time above MIC vs Area under the curve (AU...

„ There are multiple dosing strategies for IV antibiotics including intermittent infusion, extended infusion, and continuous infusion o These are usually optimizing depending on the pharmacokinetics and pharmacodynamics of the drug: Time above MIC vs Area under the curve (AUC) „ Intermittent infusion is used in most antibiotic regimens „ Extended infusion and continuous are preferred for time above the MIC medications, example: beta-lactams o Extended infusion can commonly be seen in piperacillin/tazobactam (Zosyn) o Continuous infusion may also be used to facilitate outpatient administration DIFFERENT DOSING MODELS „ Penicillin and beta-lactam allergies are reported in a large population of patients, 10% o In reality less than 1% of the population are truly allergic with an IgE- mediated reaction, with many less having additional cephalosporin allergies „ Of the patients who have had a confirmed allergy, 80% do not retain it after 10 years „ Penicillin allergies have risk for cross reactivity with other beta- lactams, but this is dependent on the side chains of the antibiotics which vary greatly between the beta-lactams o Utilize antibiotics with different side chains than the one the patient had an allergy to, pharmacy can help with this o Ex. Cefazolin has a completely unique side chain so many institutions promote cefazolin for all since the likelihood of an allergy to it is extremely low PENICILLIN ALLERGY „ Culture collection is extremely important for the selecting of optimal treatments „ Targeted therapy based on a pure culture will be the most beneficial o Ex. Urine cultures need to be a clean catch or else a contaminated specimen may impact treatment o Podiatry cultures need to be deep tissue and/or bone sampling going through pathology versus just surface swab of the wound CULTURE COLLECTION „ The gold standard of appropriate infectious disease care is following the culture and susceptibility report „ Guides practitioner in selecting the narrowest spectrum antimicrobial agent and determines potential for resistance „ Most institutions utilize rapid molecular testing and identification technology (blood) to give molecular information prior to cultures finalizing to help guide therapy in a timely manner CULTURE AND SENSITIVITY „ The general principle of antimicrobial stewardship: „ Right Drug „ Right Dose „ Right Duration „ Helps to reduce incidence of adverse events, Clostridioides difficile, potential for multi-drug resistant organisms, and cost to the institution „ Stewardship will likely look different at each institution however institutions are required by CMS to participate in reporting „ Hospital accreditation organizations also require antimicrobial stewardship o Team usually includes infectious disease providers, pharmacists, nurses, lab personal, and infection prevention ANTIMICROBIAL STEWARDSHIP ANTIBIOTICS „ Penicillins, cephalosporins, monobactams, and carbapenems „ Time dependent and bactericidal „ Alt dosing regimens – “ Time over MIC” „ Percentage of a dosage interval in which the serum level exceeds the MIC „ Can adjust the dose, can adjust the infusion time, or can adjust the frequency to maximize this effect BETA-LACTAMS „ Primarily covers Strep Species „ Extremely limited MSSA coverage ( 200 hours „ Only approved for SSTI „ Used for other indications off-label for complex patients „ Frequency of repeat dosing studies ongoing (weekly infusions) „ Very expensive which leads to a difficult place in therapy o Thousands of dollars per dose LONG-ACTING MRSA AGENTS „ Treats anaerobes and C. difficile o Not preferred therapy for c. diff, usually adjunctive „ Concentration dependent and bactericidal „ Metallic taste, N/V „ Common place in therapy – add on to other antibiotics to cover anaerobes METRONIDAZOLE „ Used to treat gram positives and biofilm producing bacteria o NEVER use alone „ Monitor LFTs „ Major DDIs with P450 „ Depending on use can be bacteriostatic or bactericidal „ Concentration Dependent „ Can be IV or oral „ Commonly used for adjunctive therapy for PJI, endocarditis, or osteomyelitis in patients with hardware involvement RIFAMPIN QUESTIONS?