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Rational use of Antibiotics
- 1. RATIONAL USE OF ANTIBIOTICS DrMd Main Uddin Assistant Professor (Medicine) Cox’s Bazar Medical College
- 2. Contents Introduction Empiricversus targeted therapy Therapy with combined Antimicrobial agents Choice of a suitable drug Misuses of Antibiotics Conclusion
- 3. Introduction The globaluse of antibiotics/antibacterial drugs have improved the health of humans and animals since the antibiotic golden age and the economy of many countries worldwide. These agents are used in the treatment of both human and animal bacterial diseases. They are used by livestock farmers as feed additives to enhance growth of livestock animals. They are used in food industries as preservatives and in commercial ethanol production to prevent bacterial contaminants of
- 4. DEFINITION Antibiotics are chemicalsubstances obtained from microbes/microorganisms (bacteria, fungi, actinomycetes) that able to inhibit the growth or kill the other microorganisms. Antimicrobial all antiinfections semisynthetic synthetic nature antibiotics
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- 7. ? Bad bugs neednew drugs Linezolid
- 8. Abstract We havedone a retrospective study on morbidity and mortality of Communicable diseases in District Sadar Hospital Cox’s Bazar from July’2010 to June ’2011. All patients admitted to Medicine ward were included. Total numbers of patients are 10208, male 4959, female 5249. Total number of infectious diseases are 1641(about 16%), male 883, female 758.
- 9. UTI isthe commonest one, total 408, male 110, and female 298. Enteric fever is the second commonest cause of admission, total 246, male 152, and female 94. Tuberculosis is still a major threat to community, total 98 pulmonary and 23 extra pulmonary cases are found. In 433 cases diagnosis is mentioned as AFI (Acute Febrile Illness), no etiological agent mentioned, viral infection is a logical possibility. Other top four causes of admission to medicine ward are Acute Viral Hepatitis (AVH) (124), Upper Respiratory Tract Infection (URTI) (95), Malaria (69) and
- 10. RATIONAL PRESCRIBING Like anyother process in health care, writing a prescription should be based on a series of rational steps. (1) Make a specific diagnosis: Prescriptions based merely on a desire to satisfy the patient's psychological need for some type of therapy are often unsatisfactory and may result in adverse effects. (2) Consider the pathophysiologic implications of the diagnosis: If the disorder is well understood, the prescriber is in a much better position to offer effective therapy.
- 11. (3) Select aspecific therapeutic objective (4) Select a drug of choice (5) Determine the appropriate dosing regimen (6) Devise a plan for monitoring the drug's action and determine an end point for therapy (7) Plan a program of patient education
- 12. Empiric versus targetedtherapy
- 13. Therapy with Combined AntimicrobialAgents Indications for the Clinical Use of Combinations of Antimicrobial Agents Use of a combination of antimicrobial agents may be justified (1) for empirical therapy of an infection in which the cause is unknown, (2) for treatment of polymicrobial infections, (3) to enhance antimicrobial activity (i.e., synergism) for a specific infection, or (4) to prevent emergence of resistance.
- 14. Empirical Therapy ofSevere Infections in Which a Cause Is Unknown In the treatment of community-acquired pneumonia, a macrolide is used for atypical organisms such as Mycoplasma, and cefuroxime is used for pneumococci and gram- negative pathogens.
- 15. Treatment of Polymicrobial Infections Treatment of intra-abdominal, hepatic, and brain abscesses and some genital tract infections may require the use of a drug combination to eradicate these typically mixed aerobic-anaerobic infections.
- 16. Enhancement of Antibacterial Activityin the Treatment of Specific Infections Perhaps the best-documented example of the utility of a synergistic combination of antimicrobial agents is in the treatment of enterococcal endocarditis. In vitro, penicillin alone is bacteriostatic against enterococci, whereas a combination of penicillin and streptomycin or gentamicin is bactericidal. B-Lactam antibiotic-aminoglycoside combinations have been recommended in the therapy of infections with Pseudomonas aeruginosa.
- 17. Combination therapyhas been advocated for the treatment of infections caused by other gram-negative rods. However, the benefits of using a drug combination over a single, effective agent remain largely unproven. The combination of a sulfonamide and an inhibitor of dihydrofolate reductase, such as trimethoprim, is synergistic owing to the blocking of sequential steps in microbial folate synthesis. A fixed combination of sulfamethoxazole and trimethoprim, which is active against organisms that may be resistant to sulfonamides alone, is effective for the treatment of urinary tract infections, Pneumocystis pneumonia, typhoid fever, shigellosis, and certain infections owing to ampicillin-resistant Haemophilus influenzae.
- 18. Prevention of theEmergence of Resistant Microorganisms The theoretical basis for combination therapy of tuberculosis is to prevent the emergence of resistant mutants that might result from monotherapy. Combination therapy of Helicobacter pylori infection.
- 19. Disadvantages of Combinations ofAntimicrobial Agents Disadvantages of antimicrobial combinations include increased risk of toxicity from two or more agents, selection of multiple-drug-resistant microorganisms, eradication of normal host flora with subsequent superinfection, and increased cost to the patient.
- 20. Choice of asuitable drug Before selecting an antibacterial the clinician must first consider two factors—the patient and the known or likely causative organism. Factors related to the patient which must be considered include history of allergy, renal and hepatic function, susceptibility to infection (i.e. whether immunocompromised), ability to tolerate drugs by mouth, severity of illness, ethnic origin, age, whether taking other medication and, if female, whether pregnant, breast-feeding or taking an oral contraceptive.
- 21. The doseof an antibacterial varies according to anumber of factors including age, weight, hepatic function, renal function, and severity of infection. The prescribing of the so-called ‘standard’ dose in serious infections may result in failure of treatment or even death of the patient; therefore it is important to prescribe a dose appropriate to the condition.
- 22. An inadequatedose may also increase the likelihood of antibacterial resistance. On the other hand, for an antibacterial with a narrow margin between the toxic and therapeutic dose (e.g. an aminoglycoside), it is also important to avoid an excessive dose and the concentration of the drug in the plasma may need to be monitored.
- 23. The routeof administration of an antibacterial often depends on the severity of the infection. Life-threatening infections require intravenous therapy. Antibacterials that are well absorbed may be given by mouth even for some serious infections. Parenteral administration is also appropriate when the oral route cannot be used (e.g. because of vomiting) or if absorption is inadequate. Whenever possible, painful intramuscular
- 24. Duration oftherapy depends on the nature of the infection and the response to treatment.
- 25. Misuses of Antibiotics Treatment of Nonresponsive Infections. A common misuse of these agents is in infections that have been proved by experimental and clinical observation to be nonresponsive to treatment with antimicrobial agents. Most of the diseases caused by viruses are self- limited and do not respond to any of the currently available anti-infective compounds. Thus, antimicrobial therapy of measles, mumps, and at least 90% of infections of the upper respiratory tract and many GI infections is ineffective and, therefore, useless.
- 26. Therapy of Feverof Unknown Origin Fever persisting for 2 or more weeks, commonly referred to as fever of unknown origin, has a variety of causes, of which only about one-quarter are infections. Some of these infections (e.g., tuberculosis or disseminated fungal infections) may require treatment with antimicrobial agents that are not used commonly for bacterial infections. Others, such as occult abscesses, may require surgical drainage or prolonged courses of pathogen-specific therapy, as in the case of bacterial endocarditis.
- 27. Inappropriately administeredantimicrobial therapy may mask an underlying infection, delay the diagnosis, and by rendering cultures negative, prevent identification of the infectious pathogen. Noninfectious causes, including regional enteritis, lymphoma, renal cell carcinoma, hepatitis, collagen-vascular disorders, and drug fever, do not respond to antimicrobial agents at all. Rather than embarking on a course of empirical antimicrobial therapy for fever of unknown origin, the physician should search for its cause.
- 28. Improper Dosage Dosingerrors, which can be the wrong frequency of administration or the use of either an excessive or a subtherapeutic dose, are common. Although antimicrobial drugs are among the safest and least toxic of drugs used in medical practice, excessive amounts can result in significant toxicities, including seizures (e.g., penicillin), vestibular damage (e.g., aminoglycosides), and renal failure (e.g., aminoglycosides), especially in patients with impaired drug excretion or metabolism. The use of too low a dose may result in treatment failure and is most likely to select for microbial resistance.
- 29. Inappropriate Reliance on ChemotherapyAlone Infections complicated by abscess formation, the presence of necrotic tissue, or the presence of a foreign body often cannot be cured by antimicrobial therapy alone. As a general rule, when an appreciable quantity of pus, necrotic tissue, or a foreign body is present, the most effective treatment is an antimicrobial agent given in adequate dose plus a properly performed surgical procedure.
- 30. Lack of AdequateBacteriological Information Frequent use of drug combinations or drugs with the broadest spectra is a cover for diagnostic imprecision. The agents are selected more likely by habit than for specific indications, and the dosages employed are routine rather than individualized on the basis of the clinical situation, microbiological information, and the pharmacological considerations.
- 31. Misuses of Antibioticswith positive Widal test
- 33. Percent change inantibiotic consumption, out-patient care in 25 European countries 1997-2003 Data from ESAC -20 -15 -10 -5 0 5 10 15 20 25 Poland C roatia G reece Ireland Portugal D enm ark Luxem bourg H ungary Italy Slovakia Israel N orw ay Sw eden Austria Slovenia Estonia Finland Spain The N etherlands G erm any Belgium Iceland C zech R epublic U K France Percentchange For Iceland, total data (including hospitals) are used Co-ordination programs and national campaigns Slide courtesy of Otto Cars, STRAMA, Sweden
- 34. An exampleof a rational approach to the selection of an antibacterial is treatment of a urinary-tract infection in a patient complaining of nausea and symptoms of a urinary-tract infection in early pregnancy.
- 35. The organismis reported as being resistant to ampicillin but sensitive to nitrofurantoin (can cause nausea), gentamicin (can be given only by injection and best avoided in pregnancy), tetracycline (causes dental discoloration) and trimethoprim (folate antagonist therefore theoretical teratogenic risk), and cefalexin. The safest antibiotics in pregnancy are the penicillins and cephalosporins; therefore, cefalexin would be indicated for this patient.
- 37. Conclusion Massive useof the antibiotics/antibacterial drugs in irrational manner has affected the ecosystem, destruction of useful bacteria in the environment including the normal flora as well as increasing the selection of the pathogenic antibiotic resistant bacterial organisms that have led to their spread globally. These problems are likely to increase in future unless there is an urgent instituting of control measures involving all stakeholders on the rational use of antibiotics/antibacterial drugs globally.
- 38. Treat bacteria notfever
- 39. “The desire toingest medicines is one of the principal features which distinguish man from the animals” William Osler 1920
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