Chemotherapy protocols

Anti microbial ( antibiotics ) chemotherapy have had a major impact on life threatening infections 

ANTIMICROBIAL CHEMOTHERAPY PROTOCOLS

One of the greatest triumphs of modern medicine has been the introduction of a rational system of antimicrobial chemotherapy to fight against infectious diseases. Since time immemorial, people have used use mussels or mussel extracts to treat infections. In the early days of microbiology, an attempt was made to use extracts of fungal cultures to prevent infections of surgical wounds.

PRINCIPLES OF USE

Antibiotics are among the safest  of medicines, especially for  community infections, and a significant impact on life-threatening infections and reduce morbidity associated with many common infectious disease.This in turn is partly responsible for the overprescribing of these drugs, which led to concern about the increasing resistance to antibiotics.

Most antibiotic prescribing, particularly in the community, is empirical. While in hospital practice, microbiological documentation of the nature of infection and the sensitivity of the pathogen is not usually available for a day or two. the initial choice of treatment depends on clinical diagnosis and in turn a provisional microbiological diagnosis. This treatment "blind therapy targeting the pathogen most likely responsible for a specific syndrome, such as meningitis, urinary tract infection or pneumonia. Initial critically ill patients are often broad to cover the range of possible pathogens, but should be reduced when the microbiological data available.

BACTERICIDAL VERSUS BACTERIOSTATIC

In most infections there is no conclusive evidence that bactericidal drugs (penicillins, cepholosporins, aminoglycosides) are more effective than bacteriostatic drugs, but it is generally considered necessary to resort to the former i treat bacterial endocarditis in patients with mechanisms host defense are involved, particularly those with neutropenia. drug combinations are often necessary for reasons other providin spectrum covers - large. Initially Tuberculosis  is treated with three or four agents to avoid resistance to inhibition emerging.Synergistic is obtained through the use of penicillin and gentamicin in enterococcal endocarditis or gentamicin and ceftazidime in life - threatening Pseudomonas infection.

PHARMACOKINETIC FACTORS

To be successful enough to receive an antibiotic to penetrate the site of infection. Knowledge of standard pharmacokinetic aspects of absorption, distribution, metabolism and excretion of drugs have varied. difficult areas are the brain, eye and prostate cancer, but loculated abscesses are inaccssible most authors. Many of mild to moderate infections can be treated is compatible. Parenteral administration is reported seriously ill patients to ensure a rapid blood and tissue concentrations of antibiotics drug.Some only be administered parenterally, such as aminoglycosides and broad-spectrum cephalosporins. parenteral therapy is needed even to those who are unable to swallow or if gastrointestinal absorption is unreliable.

ANTIBIOTIC CHEMOPROPHYLAXIS

These are some indications the use of condoms antibiotics.These understand the conditions where the risk of infection is high (colon surgery), or the consequences of a severe infection (endocarditis, sepsis, post-splenectomy). The selection is determined by representatives of the likely risk of infectious disease and confirmed the efficacy and safety of treatment..... read more

Chemotherapy regimens

ANTIMICROBIAL CHEMOTHERAPY REGIMENS

DOSE AND DURATION OF THERAPY

This varies depending on the nature, severity, and response to therapy. The long-term treatment (up to 6 weeks) is required for some varieties of infective endocarditis when pulmnary tuberculosis were treated for at least 6 months. Treat many common infections, improvement occurs within 2-3 days, when the patient is afebrile or leukocytosis have been resolved, the mouth should be considered in these parenteral therapy.Five started seven days of therapy is sufficient for most infections. A short course of therapy (3 days or less) should these symptoms of uncomplicated bacteria (cystitis), minimizing the duration of treatment reduces the risk of side effects and super-infection of Candida spp or Clostridium difficile, as well as the cost of care. Breasts that concentrates in the cell, such as erythromycin, quinolones and tetracyclines are used in the treatment of mycoplasma, brucellosis, and Legionella infections.

RENAL AND HEPATIC INSUFFICIENCY

Many drugs require dose reduction of renal failure to prevent toxic buildup. This is particularly true beta lactums and aminoglycosides. Nalidixic acid and tetracycline, other doxycyclines, should be avoided. This hepatic impairment, caution and the dose should be reduced by agents such as isoniazid, ketoconazole, rifampin, and interferon.

THERAPEUTIC DRUG MONITORING

In order to ensure more non-toxic concentrations of therapeutic drugs, drugs such as aminoglycosides and vancomycin serum monitored, especially those with impared renal or change function.Peak (after 1 hour - the dose) and through the (pre-dose) on serum samples be tested. However, the increasing use of once daily doses of aminoglycosides, but the time randm serum analysis are being adopted.

MECHANISMS OF ACTION AND RESISTANCE TO ANTIMICROBIAL AGENTS 

Antibiotic works in different places for bacteria. Penecillin, cephalosporins and vancomycin, erythromycin cell wall and protein synthesis aminoglycosides, rifampicin effect on RNA synthesis and effect of metronidazole, quinolones and DNA synthesis. Sulfonamides and trimethoprim are folic acid antagonists and amphotericin B to prevent the synthesis of fungal sterols. Antibiotic resistance may be due to:

•  Failure to reach the target site, for example, because the causes of deterioration of permeability does not reach the outer membrane of    bacteria (eg, penicillin and Gram-negative).
•  Enzyme inactivation (eg, enzymes beta-lactamase).
•  Change the target site (eg, a point mutation in E. coli penicillin binding protien Strep.pneumoniae lead to resistance.

The development or acquisition of resistance to an antibiotic that the bacteria always involves either a mutation in a single point in a gene or transfer of genetic material from another organism. large fragments of DNA can be introduced into bacteria either by transfer of " naked " DNA or by a bacteriophage (a virus) DNA vector.Both the past (processing), and one (transduction) depend integration of new DNA into the chromosomal DNA recipient. This requires a high degree of homology between donor and recipient of the chromosomal DNA. Finally, resistance to antibiotics can be transferred from one bacterium to another by conjugation, where DNA extrachromosomal (plasmid) that contains resistance factor (R factor) is transferred from one cell to another by contact Direct. Transfer of these plasmids R factors can occur between unrelated bacterial strains and involve large amounts of DNA and often code for multiple resistance antbiotic.

The transformation is probably the least clinically relevant mechanism, while the transduction and transfer of R factors are generally responsible for the immediate emergence of antibiotic resistance in bacteria, increasing resistance to many antibiotics has developed...... read more