Antimicrobials dosing

Do any of the antimicrobial doses need to be adjusted for changes in organ function ... 

The goal of antimicrobial dosing for surgical prophylaxis is to maintain antibiotic concentrations above the minimum inhibitory concentration (MIC) of suspected organisms for the duration of the operation. 

Infectious diseases pharmacists typically practice in a hospital setting that allows them to devote all their time to managing antimicrobial therapy. All aspects of infectious diseases pharmacotherapy, including interventions on antimicrobial selection, antimicrobial dosing, and intravenous-to-oral conversion are the responsibility of the infectious diseases pharmacist. In addition, the pharmacist is usually responsible for analyzing new antimicrobials for formulary inclusion, medication use evaluations, and antimicrobial restriction or therapeutic interchange policies. 

Single-dose preparations intended for use in eye surgery do not contain excipient ingredients, in order to avoid tissue irritation. However, multiple-dose containers may require antioxidants (qv), antimicrobial preservatives, or buffers to maintain stabiHty and stefiHty. Such solutions are packaged in polyethylene flexible dropper units called droptainers or in glass dropper botdes. 

Russell D, Bakhtyari A, Jazrawi RP, Whitlock L, Ridgway C, McHale M, Abel S (2003) Multiple dose study to investigate the safety of UK-427,857 (100 mg or 300mg) BID for 28 days in healthy males and females. In 43rd interscience conference on antimicrobial agents and chemotherapy, Chicago, IL, USA... 

The activity of diamidines is reduced by acid pH and in the presence of blood and serum. Microorganisms may acquire resistance by serial subculture in the presence of increasing doses of the compounds. Propamidine and dibromopropamidine, as the isethionate salts, are the major diamidine derivatives employed as antimicrobial agents propamidine in the form of eye-drops (0.1%) for amoebic infection and dibromopropamidine for topical treatment of minor infections. 

Chloroquine, dapsone, methylene blue (doses >4 mg/kg), nitrofurantoin, phenazopyridine, primaquine, rasburicase, and sulfonamide antimicrobials... 

Drug-specific considerations in antimicrobial selection include the spectrum of activity, effects on nontargeted microbial flora, appropriate dose, pharmacokinetic and pharmacodynamic properties, adverse-effect and drug-interaction profile, and cost. 

Host factors can help to ensure selection of the most appropriate antimicrobial agent. Age is an important factor in antimicrobial selection. With regard to dose and interval, renal and hepatic function varies with age. Populations with diminished renal function include neonates and the elderly. Hepatic function in the neonate is not fully developed, and drugs that are metabolized or eliminated by this route may produce adverse effects. For example, sulfonamides and ceftriaxone may compete with bilirubin for binding sites and may result in hyperbilirubinemia and kernicterus. Gastric acidity also depends on... 

Recognizing the presumed site of infection and most common pathogens associated with the infectious source should guide antimicrobial choice, dose, and route of administration. For example, community-acquired pneumonia is caused most commonly by S. pneumoniae, E. coli is the primary cause of uncomplicated UTIs, and staphylococci and streptococci are implicated most frequently in skin and skin-structure infections (e.g., cellulitis). 

Provide patient education with regard to appropriate use of antimicrobials (e.g., dose, interval), adverse effects, and drug interactions (which may play a role in therapy failure and increased toxicity). 

Discuss the pathophysiology of CNS infections and the impact on antimicrobial treatment regimens (such as dosing and CNS penetration). 

Prompt initiation of intravenous high-dose cidal antimicrobial therapy directed at the most likely pathogen (s) is essential due to the high morbidity and mortality associated with CNS infections parenteral (intravenous) therapy is administered for the full course of therapy for CNS infections to ensure adequate CSF penetration throughout the course of treatment. 

Pathogen Recommended and Alternative Antimicrobial Therapy (Adult Doses Pediatric Doses) Adverse Effects/Safety Monitoring Duration (Days)... 

High-dose penicillin G traditionally has been the drug of choice for the treatment of pneumococcal meningitis. However, due to increases in pneumococcal resistance, the preferred empirical treatment now includes a third-generation cephalosporin in combination with vancomycin.13 All CSF isolates should be tested for penicillin and cephalosporin resistance by methods endorsed by the CLSI. Once in vitro sensitivity results are known, therapy may be tailored (Table 67-3). Patients with a history of type I penicillin allergy or cephalosporin allergy may be treated with vancomycin. Treatment should be continued for 10 to 14 days, after which no further maintenance therapy is required. Antimicrobial prophylaxis is not indicated for close contacts. 

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