Principles Of Antibiotics use Abdulrahman M. Al Mazrou, FRCPC Professor of Pediatrics,KSU Consultant, Pediatric Infectious diseases,KFMC Rajab-1431

ANTIBIOTICS ARE NOT ANTI-PYRETICS Principles of antibiotics use

  Abx are widely used  Frequently abused  Impact on individual and society WHY ?

References & Further Readings References & Further Readings R. Ress & R. Betts (ed): A practical approach to infectious dis 3rd Edition R. Ress & R. Betts (ed): A practical approach to infectious dis 3rd Edition Chavez-Bueno S, Stull T.Infect Dis Clin N Am2009;865 Chavez-Bueno S, Stull T.Infect Dis Clin N Am2009;865 Hassan M., Kaye D. Inf Dis Clinic NAm, Sept 1995 Hassan M., Kaye D. Inf Dis Clinic NAm, Sept 1995 R. Finch. Medicine. Vol 27, 1996 R. Finch. Medicine. Vol 27, 1996 Pong A, Bradley J. Pediat Clin N Am 2005;52: Pong A, Bradley J. Pediat Clin N Am 2005;52: Principles of antibiotics use

Is an antibiotic indicated? Is an antibiotic indicated? Have appropriate specimens been obtained? Have appropriate specimens been obtained? What organisms are likely to be responsible? What organisms are likely to be responsible? Which agent is best? Which agent is best? Is an antibiotic combination appropriate ? Is an antibiotic combination appropriate ? Consider the Followings: Principles of antibiotics use

Consider the Followings: Any special host factors? Any special host factors? Best route of administration Best route of administration What is the appropriate dose? What is the appropriate dose? Is modification needed later? Is modification needed later? Optimal duration of therapy? Optimal duration of therapy? Principles of antibiotics use

Consider the Followings: Is an antibiotic indicated? Is an antibiotic indicated? Have appropriate specimens been obtained? Have appropriate specimens been obtained? What organisms are most likely to be responsible? What organisms are most likely to be responsible? Which agent is best? Which agent is best? Is an antibiotic combination appropriate? Is an antibiotic combination appropriate? Principles of antibiotics use

Is An Antibiotic Indicated? Clinical diagnosis of bacterial infection. Clinical diagnosis of bacterial infection. Localized : e.g.cellulitis, pneumonia, etc. Localized : e.g.cellulitis, pneumonia, etc. Probable bacterial infection Probable bacterial infection Urgent situations Urgent situations Non- urgent situations Non- urgent situations Principles of antibiotics use

Consider the Followings: Is an antibiotic indicated? Is an antibiotic indicated? Have appropriate specimens been obtained? Have appropriate specimens been obtained? What organisms are most likely to be responsible? What organisms are most likely to be responsible? Which agent is best? Which agent is best? Is an antibiotic combination appropriate? Is an antibiotic combination appropriate? Principles of antibiotics use

Have Appropriate Specimens been Obtained? Important to: Important to: Optimize chance of microbiological Dx.Optimize chance of microbiological Dx. Help tailor therapy to specific pathogen.Help tailor therapy to specific pathogen. Should be: Should be: ReliableReliable AdequateAdequate Appropriately transported and processedAppropriately transported and processed Principles of antibiotics use

Consider the Followings: Is an antibiotic indicated? Is an antibiotic indicated? Have appropriate specimens been obtained? Have appropriate specimens been obtained? What organisms are likely to be responsible? What organisms are likely to be responsible? Which agent is best? Which agent is best? Is an antibiotic combination appropriate? Is an antibiotic combination appropriate? Cont… Principles of antibiotics use

What organisms are likely to be responsible? “Best Educated Guess? Based on: Based on: Hx & P.E.Hx & P.E. Patient agePatient age Epidemiological dataEpidemiological data ◘ Hospital-acquired vs. community-acquired ◘ Prior antibiotic use Prior culture dataPrior culture data Principles of antibiotics use

Consider the Followings: Is an antibiotic indicated? Is an antibiotic indicated? Have appropriate specimens been obtained? Have appropriate specimens been obtained? What organisms are most likely to be responsible? What organisms are most likely to be responsible? Which agent is best? Which agent is best? Is an antibiotic combination appropriate? Is an antibiotic combination appropriate? Cont… Principles of antibiotics use

Which Agent is Best? A perfect antibiotic is: A perfect antibiotic is: Specific for targeted pathogensSpecific for targeted pathogens Adequate at site of infectionAdequate at site of infection Proven efficacyProven efficacy Minimal alteration of host natural floraMinimal alteration of host natural flora SafeSafe CheapCheap Principles of antibiotics use

Consider the Followings: Is an antibiotic indicated? Is an antibiotic indicated? Have appropriate specimens been obtained? Have appropriate specimens been obtained? What organisms are most likely to be responsible? What organisms are most likely to be responsible? Which agent is best? Which agent is best? Is an antibiotic combination appropriate? Is an antibiotic combination appropriate? Principles of antibiotics use

Is an Antibiotic Combination Appropriate? Indications Indications Increase spectrum of coverage.Increase spectrum of coverage. Multiple organisms proven or likely.Multiple organisms proven or likely. Synergism.Synergism. Prevention of emergence of resistance.Prevention of emergence of resistance. Cont… Principles of antibiotics use

II Indifference Log of number if viable bacteria/mL SynergismAntagonism No drug Drug A Drug C Drug B Drug A A + B A + C Hours after inoculation I III

Disadvantages of combinations: Disadvantages of combinations: Increase adverse effectsIncrease adverse effects Increase colonization with resist. organismsIncrease colonization with resist. organisms Possibility of antagonismPossibility of antagonism Increase costIncrease cost Is an Antibiotic Combination Appropriate? Is an Antibiotic Combination Appropriate? Principles of antibiotics use

Any special host factors? Any special host factors? Best route of administration? Best route of administration? What is the appropriate dose? What is the appropriate dose? Is modification needed later? Is modification needed later? Optimal duration of therapy? Optimal duration of therapy? Consider the Followings: (Cont…) Principles of antibiotics use

Consider Special Host Factors: Genetic e.g. G6PD Genetic e.g. G6PD Renal function Renal function Liver function Liver function Pregnancy & Lactation Pregnancy & Lactation Drug interaction Drug interaction Principles of antibiotics use

Any special host factors? Any special host factors? Best route of administration? Best route of administration? What is the appropriate dose? What is the appropriate dose? Is modification needed later? Is modification needed later? Optimal duration of therapy? Optimal duration of therapy? Consider the Followings: (Cont…) Consider the Followings: (Cont…) Principles of antibiotics use

Best Route of Administration Determined by: Determined by: Nature of infectionNature of infection Host factorsHost factors Drug factorsDrug factors Options: Options: Parenteral vs oral from startParenteral vs oral from start Sequential parenteral-oral therapySequential parenteral-oral therapy Principles of antibiotics use

Any special host factors? Any special host factors? Best route of administration? Best route of administration? What is the appropriate dose? What is the appropriate dose? Is modification needed later? Is modification needed later? Optimal duration of therapy? Optimal duration of therapy? Consider the Followings: (Cont…) Principles of antibiotics use

What is the appropriate dose? Avoid sub-therapeutic doses Avoid sub-therapeutic doses Determined by: Determined by: Serious vs non-serious infectionsSerious vs non-serious infections Site of infectionSite of infection Drug PK/PD propertiesDrug PK/PD properties Other host factors (e.g. renal function … etc)Other host factors (e.g. renal function … etc) Principles of antibiotics use “ Lowest dose that is effective ”

Any special host factors? Any special host factors? Best route of administration? Best route of administration? What is the appropriate dose? What is the appropriate dose? Is modification needed later? Is modification needed later? Optimal duration of therapy? Optimal duration of therapy? Consider the Followings: (Cont…) Principles of antibiotics use

Any Modification Needed? Any Modification Needed? Principles: Principles: Narrow vs broad spectrum agents. Narrow vs broad spectrum agents. Least toxic agent. Least toxic agent. Cheaper. Cheaper. Principles of antibiotics use

Any special host factors? Any special host factors? Best route of administration? Best route of administration? What is the appropriate dose? What is the appropriate dose? Is modification needed later? Is modification needed later? Optimal duration of therapy? Optimal duration of therapy? Consider the Followings: (Cont…) Consider the Followings: (Cont…) Principles of antibiotics use

Optimal Duration of Therapy Optimal Duration of Therapy Established vs empirical. Established vs empirical. Avoid prolonged courses: Avoid prolonged courses: increase adverse effectsincrease adverse effects increase cost.increase cost. Principles of antibiotics use

New is not always better! New is not always better! Most are expensive Most are expensive Less experience Less experience New VS Current Antimicrobial Agent Principles of antibiotics use

New VS Current Antimicrobial Agent ( 2 ) Know: Know: approved indicationsapproved indications advantages vs disadvantagesadvantages vs disadvantages basic pharmacokineticsbasic pharmacokinetics ◘ serum T ½ ◘ activity at various site ◘ …etc. common adverse effectscommon adverse effects Principles of antibiotics use

Accept new agents with : Accept new agents with : significant advantagessignificant advantages extensive testingextensive testing New VS Current Antimicrobial Agents ( 3 ) Principles of antibiotics use

Criteria for Use of New Agent Antimicrobial activity is superior Antimicrobial activity is superior Have a therapeutic advantage Have a therapeutic advantage Better pharmacokinetics Better pharmacokinetics –Site penetration –Longer t ½ –Shorter duration Less toxic Less toxic Better tolerance Better tolerance Principles of antibiotics use

Acetaminophenis the antipyretic the antipyretic of choice Principles of antibiotics use

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