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guidelinesforantibiotics-200827064818.pdf
- 1. Guidelines for rational use of antibiotics in surgical prophylaxis DR. M. LAKSHMI GAYATHRI, PHARM D ASSISTANT PROFESSOR
- 2. Introduction: Introduction: Rational use of antibiotics is extremely important as injudicious use can adversely affect the patient, cause emergence of antibiotic resistance and increase the cost of health care. Need of antibiotics: antibiotics are genrally only useful for the treatment of bacterial infectios Majority of the infectionsseen in general practice which are of viral origin and in that casse antibiotics can neither treat such as a viralinfcetions nor to prevent secondary bacterial infections in those patients
- 3. Selection of antibiotics: 3 main factors are needed to be considered in the process of selection of antibiotics. 1. based on patient 2. based on etiological agent 3. based on pharmacokinetic properties Based on patient: several factors have to be considered in selecting an antibiotic to patient. 1. Age: very young and very old tend to be more prone to adverse effects of antibiotics Neonates have immature liver and renal functions which affect their ability to metabolise or excrete antibiotics Elder patients suffer from nephrotoxicity and allergic reactions
- 4. Pregnancy: antibiotics should be avoided in pregnancy and if it is necessary to use an antibiotics , then 硫lactam antibiotics and erythromycin are probablythe most safest. Infections: in serious infections like meningitis and incase of bacteremic shock, the immediate institution of best available antibiotics is more preferable for the suspected pathogen. With delayed treatment it will increase the both morbidity and mortality. In less serious situation like otitis media where a spontaneous recovery is most commonly required then a general antibiotics are adequate.
- 5. Patients with hepatic or renal impairment : In case of antibiotic use in these elderly patients with renal or hepatic impairment the dose modification should be followed. 2. Based on etiological agent: determination of etiological agent( infectious agent) which is depends on a combination of clinical aspect as well a laboratory values. Even though the bacteriological report is available , it indicates that best antibiotics are used for the treatment.
- 6. 3. based on pharmacokinetic properties: generally physicians should have the adequate knowledge of pharmacokinetic properties of antibiotics Factors affecting these properties: >Route of administration: antibiotics vary in their ability to be absorbed orally or to cross BBB and some of these factors will affect their route of administration. >Therapeutic concentration: the ability of antibiotics to achieve the therapeutic concentrations at the site of infections is an another important considerationlike when antibiotics used for UTI they should ideally be concentrated in the urine.
- 7. Physicians should also be aware of some drug drug interactions since many antibiotics can interact with other non antibiotic drugs in a condition where a minimum duration of treatment has been established. infections minimum duration of treatment tuberculosis 4-6 months endocarditis 4 weeks pneumonia 5 days
- 8. Antibiotics for surgical prophylaxis: they are used to prevent infections at the surgical site. Prophylaxis is become standard for contaminated and clean contaminated surgery and also for surgery involved in the insertion of artificial devices A single dose of antibiotics is usually sufficient, if the duration of the surgery is four hours or even less and it should be given at correct time prior to surgery before one hr or 30 min. Inappropriate use of antibiotics for surgical prophylaxis increases both cost and also favour the emergence of resistance bacteria.
- 9. Principles of surgical antibiotic prophylaxis: first decide if prophylaxis is appropriate. choose the less expensive drug if two are of with equal antibacterial spectrum, efficacy, toxicity, and ease of administration. Administer dose at right time and also for short period of time Avoid antibiotics which are used in the treatment of serious sepsis Do not use antibiotic prophylaxis to overcome poor surgical technique Review the protocols of prophylactic antibiotics regularly as both cost and hospital antibiotic resistance patterns may change
- 10. Indications for antibiotics in surgical prophylaxis: a classification system which ranks procedures according to their potential risk for infectious complications has facilitated the procedures for the study of antibiotic surgical prophylaxis. clean clean- contaminated contaminated The most widely accepted indications fro the antibiotics prophylaxis are contaminated and clean contaminated surgery and operations involving the insertion of an artificial device. Less accepted for clean operations in pts with impaired host defences or for neurosurgery, heart surgery or any ophthalmic surgeries.
- 12. Choice of antibiotics: choice is based on several factors Always ask the patient about a prior history of antibiotic allergy, as beta lactams are the commonest type of antibiotics used in prophylaxis a history of severe penicillin allergy (anaphylaxis, angioedema), cephalosporins are also contraindicated, as there is a small but significant risk of cross reaction. Always select an antibiotics with narrowest antibacterial spectrum , to reduce the emergence of multi resistance pathogens If the pt develops sever sepsis then broad spectrum antibiotics should be selected.
- 13. The use of third generation cephalosporins such as ceftriaxone and cefotaxime should be avoided in surgical prophylaxis Often several antibiotics are equal in terms of antibacterial spectrum, efficacy, toxicity, and ease of administration if so, the least should be choosen as antibiotics for surgical prophylaxis comprise a large portion of hospital pharmacy budgets Commonly used surgical prophylaxis are IV first generation cephalosporins- cephazolin or cephalothin IV gentamicin
- 14. IV or Rectal metronidazole if anerobic infection is likely present Oral tinidazole IV flucloxacillin if methicillin suscepitible staphylococcal infection is likely IV vancomycin in case of methicillin resistant staphylococcal infection
- 16. Route and frequency of antibiotic administration: Oral and rectal antibiotics need to be given earlier to ensure adequate tissue concentration during surgery Metronidazole suppositories are commonly use in bowel surgery and must be given 2-4 hrs before surgery Generally topical antibiotics are not recommended with exceptions of ophthalmic and burns surgeries
- 17. Prophylactic antibiotics are usually given IV as a bolus on induction of anesthesia t ensure adequate tissue concentration at the time of surgical incision IM antibiotics are less used than IV .they are typically given at the time of pre medications so that peak tissue levels are attained at most critical time.