Infection drug considerations

Unit II contains 11 chapters that present the anti-infective drugs, grouped according to classification. These shorter chapters allow for more inclusive coverage of the different types of anti-infectives and the appropriate nursing considerations for each classification. 

Recently, Tsakala et al. (90) formulated pyrimethamine systems based on several lactide/glycolide polymers. These studies were conducted with both microspheres (solvent evaporation process) and implants (melt extrusion process). In vitro studies indicated that pyrimethamine-loaded implants exhibited apparent zero-order release kinetics in aqueous buffer whereas the microspheres showed an initial high burst and considerably more rapid drug release. In vivo studies in berghi infected mice confirmed that the microspheres did not have adequate duration of release for practical application. However, the implants offer promise for future clinical work as more than 3 months protection was observed in animals. 

A variety of other clinically important infections, such as brucellosis, listeriosis, salmonellosis, and various Mycobacterium infections, are of interest as these are often localized in organs rich in MPS cells. Liposome encapsulation has been demonstrated to improve therapeutic indices of several drugs in a number of infectious models. The natural avidity of macrophages for liposomes can also be exploited in the application of the vesicles as carriers of immunomodulators to activate these cells to an microbicidal, antiviral, or tumoricidal state. These studies were recently reviewed by Emmen and Storm (1987), Popescu et al. (1987), and Alving (1988). In addition to the treatment of "old" infectious diseases, the concept of MPS-directed drug delivery is of considerable interest for the therapy AIDS, possibly enabling control of human immunodeficiency virus replication in human macrophages. 

Over 10000 quinolone antibacterial agents have now been synthesized. Nalidixic acid is regarded as the progenitor of the new quinolones. It has been used for several years as a clinically important drug in the treatment of urinary tract infections. Since its clinical introduction, other 4-quinolone antibacterials have been synthesized, some of which show considerably greater antibacterial potency. Furthermore, this means that many types of bacteria not susceptible to nahdixic acid therapy m be sensihve to the newer derivahves. The most important development was the introduction of a fluorine substituent at C-6, which led to a considerable increase in potency and spectrum of activity compared with nalidixic add. These second-generation quinolones are known as fluoroquinolones, examples of which are ciprofloxacin and norfloxacin (Fig. 5.19). 

Along with selecting an effective treatment, selection of an appropriate antifungal agent requires consideration of location and severity of infection, medication adherence, potential drug... 

Neutropenias may also arise as a side effect or deliberate consequence of therapy. For example, some drugs used in the treatment of inflammatory disorders are immunosuppressive, and if these decrease the number of circulating neutrophils to below the critical threshold level, then susceptibility to infection may result. During chemotherapy for the treatment of solid tumours, an inevitable consequence of cytotoxic therapy is that the bone marrow will be destroyed by the drugs thus, patients will have a considerable risk of infection during this induction period. Similarly, during the treatment of haematological disorders (e.g. leukemias and myelodysplastic syndromes), the aim of therapy is to attack the bone marrow so as to destroy... 

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