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ANTIBIOTICSContents IntroductionClassificationsCharacteristics of an ideal antibioticAntibiotic selectionProblems associated with antibiotics usage-lactam antibiotics Tetracyclines
Nitroimidazole derivatives Aminoglycosides Macrolides QuinolonesUse of antibiotics in endodonticsAntibiotics in pregnancyAntibiotics in lactating women Antibiotics in renal and hepatic dysfunctionAntibiotic prophylaxisConclusion References
Introduction
Drug : drug is any substance / product that is used / is intended to be used to modify / explore physiological systems / pathological states for the benefit of one recipient. Chemotherapy : it is the treatment of systemic infection / malignancy with specific drugs that have selective toxicity for the infecting organism / malignant cell with no / minimal effects on the host cells.
Introduction
Antibiotics These are the substance produced by the microorganisms which suppress the growth of or kill microorganisms at very low concentration.
Antibiotic (Greek-anti means against and biosis means life).
Initially term chemotherapeutic agent was used synthetic compounds.
Now both synthetic & microbiologically produced drugs need to be included
Hence the term antimicrobial agent.
Classification of AntibioticsMechanism of action
Organisms susceptible
Spectrum of activity.
Chemical structure
Sulfonamides and related drugsSulfadiazine and othersSulfones Dapsone (DDS), Paraaminosalicylic acid (PAS). Diaminopyrimidines TrimethoprimPyrimethamineQuinolonesNalidixic acid CiprofloxacinNorfloxacinTetracycline'sOxytetracyclineDoxycycline etcNitrobenzene derivative Chloramphenicol-lactam antibiotics PenicillinsCephalosporinsMonobactamsCarbapenems
AminoglycosidesStreptomycinGentamicinNeomycin etcMacrolide antibioticsErythromycinRoxithromycinAzithromycin etcPolypeptide antibioticsPolymyxin-BColistinBacitracin
GlycopeptidesVancomycinTeicoplanin OxazolidinoneLinezolidNitrofuran derivativesNitrofurantoinFurazolidoneNitroimidozoles MetronidozoleTinidazole
Nicotinic acid derivativesIsoniazidPyrazinamideEthionamide Polyene antibioticsNystatinAmphotericin-BHamycin Azole derivatives MiconazoleClotrimazoleKetoconazole
Others RifampinLincomycinClindamycinSpectinomycinSod. fusidateCycloserineViomycinGriseofulvin
Type of action Antibiotics are obtained from Characteristics of an ideal AntibioticSite of infection.Should not cause the development of resistanceUndesirable side effectsOrally without inactivation by stomach acid, or parenterally without binding to the blood proteinsConcentrations in the tissue or blood, sufficiently high to inhibit or kill the infectious agent.
Factors governing antibiotic selection Problems associated with antibiotic useNo indiscriminate & inadequate or unduly prolonged use of AMA should be made.Prefer rapidly acting & selective AMA (narrow spectrum) whenever possible.Use of combination of AMA whenever prolonged therapy is undertaken.Infection by organisms notorious for developing resistance must be treated intensively21Penicillins First antibiotic to be used clinicallyDiscovery + 1928 Alexander Fleming , St. Marys hospital LondonPenicillium notatumPenicillium chrysogenumThiazolidine + beta lactum rings to which side chains are attachedThis side chain can be split off Other side chains then attached- Semi-synthetic Penicillins
CLASSIFICATION OF PENICILLINS Natural penicillin Penicillin G (benzyl penicillin)Procaine penicillin GBenzathine penicillin G Acid resistant penicillinPhenoxymethyl penicillin (penicillin V)Phenoxyethylpenicillin (phenethecillin)Penicillianse resistant penicillinsAcid labile methecillin, nafcillin, cloxacillin, dicloxacillinAcid resistant flucloxacillinPenicillins effective against gram positive and some gram-negative organismsAmpicillinAmoxycillinTalampicillin Extended spectrum penicillinsAminopenicillins Ampicillin AmoxycillinCarboxypenicillins carbenicillin, ticarcillinUreidopenicillins piperacillin, mezlocillinAmidino penicillins mecillinam, pivmecillinam Penicillins with betalactamase inhibitorsAmoxycillin clavulanic acid (Augmentin)
BENZYL PENICILLIN (PENCILLIN G)PnG - narrow spectrum antibiotic; activity is limited primarily to gram positive bacteria Is available in the form of water soluble sodium and potassium saltsMost potent AMA, inhibits the growth of susceptible organism.Mainly gram +ve, gram ve cocci and some gram +ve bacilli with exception of enterococci.
Mechanism of action
PeptidoglycanExposure to beta lactum antibioticsWeak points lacking peptidoglycanExposure to hypotonic environmentMembrane bulges out as water Diffuses into coilMembrane breaksCell lyses Absorption fate and excretion :About 1/3 of drug is activated on oral administration.Absorbed from the duodenum.Because of the inadequate absorption the oral dose should be 4/5 times larger than the intramuscular dose.As food interferes with its absorption PnG should be given orally at least 30 min after food or 2 to 3 hours before food. Penicillin in aqueous solution is rapidly absorbed after SC or IM administration. Peak plasma level of 8 to 10 units per ml is reached with in 15 to 30 min and drug disappears from plasma with in 3-6 hours.
Preparation and dose : PnG inj 0.5-5 MU i.m or i.v 6-12 hours Procaine penicillin inj 0.5, 1 MU dry powder in vial
Use in endodontics
Penicillin V antibiotic of choice
Effective against both facultative and anaerobic organisms found in polymicrobial endodontic infections
Loading dose 1000mg followed by 500mg 4-6 hrsSEMI SYNTHETIC PENICILLINS
The major drawbacks of benzyl penicillin are :Inactivation by the gastric hydrochloric acidShort duration of actionPoor penetration into CSFActivity mainly against gram +ve organismPossibility of anaphylaxis
The attachment of side chains are inhibited and instead various organic radicals can be substituted.
Acid resistant penicillin :
1. Potassium phenoxymethyl penicillin (penicillin V)Similar antibacterial spectrum like benzyl penicillin.More active against resistant staphylococciLess inactivated by the gastric acid.Plasma levels achieved is 2 to 5 times higher than benzyl penicillin.Available as 60 & 125 mg tablets..
2. Potassium phenoxyethyl penicillin and 3. Azidocillin Both have similar properties to penicillin V and no difference in the antibacterial effect
Extended spectrum penicillin's :Amino penicillin's Ampicillin Antibacterial activity is similar to that of PnG that is more effective than PnG against a variety of gram-ve bacteria Absorption, fate and excretion :Oral absorption is incomplete but adequateFood interferes with absorbtion Dose : 0.5-2 gm oral/IM or IV depending on severity of infection every 6 hours
Adverse effects :Diarrhoea is frequent Skin rashes is more commonUnabsorbed drug irritates lower intestinesPatient with history of hypersensitivity to PnG should not be given Ampicillin.
AMOXYCILLIN This is a semisynthetic penicillin (amino-p-hydroxy-benzylpencillin)Antibacterial spectrum is similar to ampicillinOral absorption is better; food does not interfere; higher and more sustained blood levels are produced.It is less protein bond and urinary excretion is higher than that of ampicillin.Incidence of diarrhoea is less
Dose : 0.25-1 g TDS oral
Adverse effects :Pain - thrombophebitisRashes and Diarrhoea
Use in endodontics
Expanded spectrum that includes bacteria not routinely associated with infections of endodontic origin
Ideal for medically compromised patients requiring antibiotic prophylaxis
Loading dose 1000 mg followed by 500mg - 8 hrs
Alternative dosage 875mg - 12 hrsBETA LACTAMASE INHIBITORSCLAVULANIC ACID
Streptomyces clavuligenus Inhibits beta lactamases (Gm+ve & Gm-ve) Poor intrinsic antimicrobial activity Progressive inhibitor / Suicide inhibitorRapid oral absorptionUsed with Amoxycillin - 250 mg Amoxycillin + 125 mg Clavulanic acid
Use in endodontics
Excellent results against bacteria isolated from endodontic infections (Augmentin)
Considered for immunocompromised patients
Loading dose 1000mg followed by 500mg 8 hrs
Alternative dosage 875 mg 12 hrsSULBACTUM
Semi-synthetic Beta lactamase inhibitor
Sultamicillin tosylate-salt with Ampicillin
USES Mixed infections
II) Pencillinase resistant pencillins :
Methicillin High penicillinase resistance not acid resistanceIM or IV (slow) in the dose of 1 gm every 4-6 hours.Hematuria, albuminurea and reversible interstitial nephritis are the special adverse effect of methicillin.
Cloxacillin Weaker antibacterial activity. Oral dose for adults 2-4 gm divided into 4 portions.IM adults 2-12 gm/day, children 100-300 mg/kg/day every 4-6 hours. Oxacillin, Dicloxacillin, Flucloxacillin are other penicillins similar to cloxacillin, but not marketed in India.
Mechanism of bacterial resistanceHigh-molecular-weight Penicillin Binding Proteins.Inability to penetrate to its site of action- target enzymes & PBPs are located deeper under lipoprotein barrier. Production of Penicillinase - narrow spectrum - lactamase opens lactam ring & inactivates PnG. Gram +ve elaborates larger quantities of enzyme Gram - ve elaborates in smaller quantities
Some bacteria penicillin tolerant-their target enzymes altered & have low affinity for penicillin.Gram ve have porin channels premeability differs for various lactam antibioticssome gram ve become resistant due to loss or alteration of porin channels.
Untoward reactions to penicillinNausea ,diarrhoeaThrombophlebitis Hypersensitivity reactions(0.7 % - 10 %)Serum sicknessFeverEosinophilia
QUINOLONESSyntheticActive mainly against Gram ve bacteria1st generation fluoroquinolones introduced in 1980 having one fluoro substitution.In 1990 compounds with additional fluoro & other substitution have been developed further extending antimicrobial activity & confering metabolic stability ( longer t1/2 ) these are 2nd generation fluoroquinolones.
NALIDIXIC ACIDActive against Gm-ve BacteriaBactericidalInhibits bacterial DNA GyraseAbsorbed orallyPlasma half life is 8 hrsPrimarily used as urinary antiseptic , 2nd line of drug in recurrent cases.
usesPrimarily used as urinary antiseptic , 2nd line of drug in recurrent cases.FLUOROQUINOLONESQuinolones having one /more Fluorine substitutions
Ist Generation-1 Fluorine NorfloxacinCiprofloxacinOfloxacinPefloxacin
2nd Generation More Fluorine & other substitutionLomefloxacinSparfloxacinFleroxacinAmikofloxacin
CIPROFLOXACINMost potent Ist gen FQ
Gm-ve bacilli
Rapid bactericidal & high potency
Long post-antibiotic effect
Low mutational resistance
Protective intestinal flora spared
Many B lactum & Aminoglycoside resistant
Mechanism of actionInhibit enzyme bacterial DNA gyrase- nicks double stranded DNA, introduce negative supercoils- reseals the nicked endsPHARMACOKINETICS
ADVERSE EFFECTS
Rapid oral absorptionHigh tissue penetrabilityNausea,vomitting,anorexiaDizziness,Insomnia,Anxiety,confusion,tremors,RestlessnessHypersensitivityUse in endodontics
Not effective against anaerobic bacteria that is found in endodontic infections
Indicated if culture and sensitivity tests demonstrate presence of susceptible organisms NORFLOXACIN Less potentPrimarily for UTI PEFLOXACINMethyl derivative of NorfloxacinMore lipid soluble , better penetration
OFLOXACIN Activity between Ciprofloxacin & Norfloxacin
SPARFLOXACINRecently introduced DifluorinatedEnhanced activity against Gram-ve bacteria , Anaerobes & MycobacteriaHigh efficacy in Mycobacterium Avium infections in AIDS patientCEPHALOSPORINSSemisynthetic derived from natural Cephalosporin-C (fungus- Cephalosporium)Chemically related to PenicillinsBactericidalSame mechanism of action as penicillinsInhibit cell wall synthesis
CLASSIFICATION1st Generation (1960s) Parenteral Oral Cefazolin Cephalexin Cefadroxyl Cephadrine2nd Generation Parenteral Oral Cefuroxime Cefuroxime axetil Cefaclor
Gram+veOral cavity anaerobesGram-ve3rdGeneration (1980s) Parenteral Oral Cefotaxime Cefixime Ceftazidime Ceftriaxone Ceftizoxime
4thGeneration (1990s) Parenteral Cefpirome
Highly augmented against G ve Enterobacteriae High resistance to -lactamase producing
Same abtibacterial spectrum Increased stability to -lactamaseADVERSE EFFECTS- CEPHALOSPORINSMore toxic than PenicillinsPain after I.m injectionHypersensitivity Neutropenia, ThrombocytopeniaDisulfiram like reaction with alcohol NephrotoxicityBleedingDrug interactionCephalosporins plus alcohol can cause Antabuse-like effects, Aspirin or heparin plus Cephalosporins can increase bleeding riskUse in endodontics
Not usually indicated1st gen not effective against anaerobes involved in endodontic infections2nd gen some effect however possibility of cross allerginicity with penicillin
TETRACYCLINES
Tetracyclines are napthacene derivatives.The napthacene nucleus is made up by fusion of 4 partially unsaturated cyclohexane radicals and hence the name tetracyclines.Tetracycline's are broad spectrum & bacteriostatic.
On the basis of chronology of development, convenience of description, divided into 3 groups.
Group I Group II Tetracycline Demeclocyline Oxytetracycline Methacycline Group III Doxycycline Minocycline.
Mechanism of action :Tetracyclines are thought to inhibit bacterial protein synthesis by binding to the 30 S bacterial ribosome and preventing the access of Aminoactyl RNA to the acceptor (A) sites on the mRNA ribosome complex
Antimicrobial activity :Gram +ve and ve cocci are sensitive Gram +ve bacilli are inhibitedOralParenteral Tetracycline 1-2 g/dayDoxycycline 200 mg of 1st loading dose,100 mg/dayDoxycycline 200mg then 100 mgMinocycline 200 mg then 100 mg/12 hrMinocycline 200mg then100mg/12 hr
dosePharmacokinetics : Incompletely absorbed from GIT Absorption is impaired by iron or zinc salts [due to chelation of cations] They cross the placenta and enter fetal circulation and amniotic fluid Widely distributed in liver ,bone marrow and spleenEnterohepatic circulationPrimarily excreted in urine through kidney
Adverse effects :GIT- Epigastric burning, nausea, vomiting, DiarrhoeaHepatoxicityRenal toxicityEffects on teeth-Orthophosphate complexThrombophlebitisHypersensitivity Reactions Super infectionPrecaution : Not to be used in pregnancy, lactation and in children Avoided in patients on diuretics Used cautiously in renal and hepatic insufficiency Do not mix Injectable Tc with Pn- inactivation occurs
EFFECT ON TEETH & BONES
Calcium-Tetracycline chelate
Midpregnancy-5 mth of E/U life Deciduous teeth affected
3 mth - 5 yrs Permanent anterior dentition
Late pregnancy - childhood Temporary suppression of bone growth.
Anti anabolic effect-reduce Protein synthesisIncreased intracranial pressure (infants)Vestibular toxicityHypersensitivity Superinfection most common antibiotic responsible
Use in endodontics
May be indicated when all the above antibiotics are contraindicated
Many strains have become resistant NITROIMIDAZOLESImidazole hetero cycles with a nitro group Have been used to combat anaerobic bacterial and parasitic infections. Most common example is metronidazole Diffuses into all tissues& body fluids Cross CNS & placenta Other drugs are :- Tinidazole, Secnidazole, Ornidazole Satranidazole
Metronidazole Almost complete absorptionPeak plasma con 8-13 g/ml within 0.25-4 hoursWide distributionHigh GCF and saliva concentration
MECHANISM OF ACTIONProdrug
Reduction of the nitro group of the drug by redox proteins of anaerobic org
Highly reactive Nitro radical produced
DNA helix destabilization & strand breakage
Death of the organism
CONTRAINDICATIONSNeurological disease, blood dyscrasiasPregnancy,chronic alcoholism (disulfiram like intolerance)Patients on enzyme inducer eg phenobarbitone & rifampicin may reduce its therapeutic effect
Drug Metronidazole
Tinidazole SacnidazoleOrnidazole
Plasma half-life8hrs12-16 hrs17-29 hrs
12-14 hrsDosage 400 mg tds0.5-1.0 g o.d1 g od500 mg bidAdverse effectsNausea , abdominal cramps , headache dry mouth, metallic tasteProlong therapy (CNS)Thrombophlebitis Disulfiram-like reaction- alcohol
Drug interactionsAlcoholCimetidine-metabolism increasesEnzyme inducers -Phenobarbital decreases.anticoagulantsSynergic effect Spiramycin + MetronidazoleCarcinogenic
Use in endodontics
Valuable in combination with penicillin when penicillin alone is ineffective
Loading dose 1000mg followed by 500mg 6 hrs Macrolide First discovered in 1950sMacrocyclic lactone ring with attached sugar moietyErythromycin is the prototype drug Roxithromycin, Clarithromycin & Azithromycin are the later additionsBacteriostatic at lower concentrations & bactericidal at higher concentrationAerobic gram positive cocci and bacilli
MECHANISM OF ACTION
Erythromycin binds 50S subunit of bacterial ribosome & inhibits protein synthesis PHARMACOKINETICSAcid labileAvailable as enteric coated tabletsCrosses serous membranes & placenta Does not cross blood brain barrierPlasma t is 1.5 hrPartly metabolised & excreted in bile, small amount excreted by kidneys
ADVERSE EFFECTS &DRUGINTERACTIONSFever, eosinophilia, skin eruptionsNausea, vomiting, abdominal painCholestatic hepatitis- EstolatePotentiate effect of Carbamezapine, corticosteroids, cyclosporine, digoxin, triazolam, warfarin * drug interactions are shared by clarithromycin & azithromycin
INDICATIONS & DOSAGEPrimary : Atypical Mycoplasma pneumonia, whooping cough, chancroidAlternative to Penicillin : Streptococcal pharyngitis, tonsillitis, mastoiditis, Diphtheria, Tetanus & SyphilisSecond choice drug : Penicillin resistant Staph infections, DOSAGEERYTHROMYCIN
250- 500mg/6 hrly (maximum 4g/day)ALTHROCIN 125, 250, 500mg tab or 250mg/5ml vial
AZITHROMYCIN
250-500 mg OD x 03 days
AZITHRAL, AZIWOK, AZIWIN 100, 250, 500 mg capsule ROXITHROMYCINSemi synthetic, long acting, acid stablePlasma t 12 hrsRespiratory, ENT, skin infectionROXID, RULIDE 50, 150 ,300 mg tabDose: 150-300 mg BID 30 mins before meal CLARITHROMYCINSame as RoxithromycinPlasma t 3-6 to 6-9 hrsURTI, LRTI , ENT, skin & soft tissue infectionsCLARIBID ,CLARIMAC 250, 500 mgDose : 250 - 500 mg BID x 07 days Use in endodontics
Alternative choice for patients allergic to penicillin
Clarithromycin and Azithromycin adv over erythromycin broader spectrum of activity lesser GI upset
Loading dose 500mg
Followed by 250 mg - 12 hrs (Cl) - 24 hrs (Az) Antibiotics in endodonticsMajority of infections without antibiotics
Not a substitute for timely endodontics
Chemomechanical debridement of the canal , drainage through the canal / incision and drainage bioburden healing Lack of circulation systemically administered antibiotics not effective against reservoir of microorganisms
MIC may not reach the anatomic spaces filled with purulence and edematous fluid Conditions not requiring adjunctive antibiotics
Pain without signs and syptoms a. symptomatic irreversible pulpitis b. symptomatic apical periodontitisTeeth with necrotic pulps and radiolucenciesTeeth with sinus tractLocalized fluctuant swellingsFollowing endodontic surgery
Antibiotic regimen is prescribed in conjugation with endodontic treatment when
systemic signs and symptoms of infection
Progressive persistent spread of infectionIndications for adjunctive antibiotics
Systemic involvement Fever > 1000 FLymphadenopathyTrismus
Progressive infectionsIncreased swellingCellulitisOsteomyelitis
Persistent infectionsAdministration of antibiotics
Loading dose provides initial adequate therapeutic blood levels
Continued for 2 3 days following resolution of the major signs and symptoms
7 day regimen is adequate Medications in Pregnancy.In general, every medication is assigned to a category (A,B, C, D, or X) based on how safe or risky it is to use during pregnancy
Category Athat human studies have shown no evidence of fetal harm in the first trimester or later in the pregnancy.eg Nystatin vaginal (Mycostatin)
Category B
Most antibiotics are Category B, which means that there is no known association with birth defects or other pregnancy-related complication and the drug is probably safe. These include:
AmoxicillinAmpicillinAugmentin DicloxicillinNitrofurantoinMetronidazole (although there is some controversy about taking it by mouth in the first trimester)Cephalosporins clindamycinErythromycin AzithromycinSulfa Drugs (until near term)FamciclovirAcyclovirValacyclovirCategory C
Others are Category C, meaning that either there isn't enough information or there are some concerns arising from animal studies, but no confirmation of problems like birth defects in humans. These include:
Bactrim, TrimethoprimClarithromycinCiprofloxacinFluconazoleMiconazoleTerconazoleIsoniazidRifampinMebendazoleTetanus ToxoidVaccines: hepatitis A, hepatitis B, influenza, meningococcus, pneumonia (pneumococcus), polio
Category Dclear-cut problems in pregnancy and should not be used unless there are no better alternatives. These includes:
Tetracycline derivatives, which can cause discoloration of teeth: tetracycline, doxycycline (Vibramycin), Minocin (minocycline)
Sulfa drugs - if near delivery (increase the chance of serious newborn jaundice)
Antibiotics in breast feedingAdministration of drugs to women who are breast feeding may have ill effects on the suckling infant and or affect lactation
Antibiotics whos amount is too small to be harmful to the infant / those found to be safe
Cephalosporins
Erythromycin
DrugComment / possible side effectAminoglycoside Use with special caution Risk not known, most manufacturers advice cautionAmoxicillin / AmpicillinUse with special caution Candidiasis , Diarrhoea CiprofloxacinContraindicated High concentrations in milk, arthropathyClindamycin Contraindicated Amount in milk small , risk of diarrhoeaMetronidazole Significant amount in milk ,Avoid Penicillins Toxicity unlikely but risk of allergySulphonamides Use with special caution Rashes, small risk of kernicterus, hemolysis in G6PD deficientTetracycline Contraindicated Growth retardation, candidiasis, tooth discolouration DRUGS TO BE USED WITH SPECIAL CAUTION / CONTRAINDICATED IN BREAST FEEDING WOMEN compromised renal or hepatic function
Patients with liver or renal disease may sometimes need to use antibiotics for unrelated infections and various surgical and dental procedures.
In order to avoid drug toxicity the prescriber must be aware of how the drug will be matabolized and eliminated when selecting a drug or determining dosage as these are the most common routes of elimination.
Liver complicated functions and
One of the most important detoxification of drugsPatients with a pre-existing liver disorder, the detoxification function compromised substances that would normally be metabolized could actually accumulate in the liver or in the bloodstream
ToxicBeside excretory role in elimination of many antibiotics, there is intensive metabolism and secretion in kidney, which is essential for normal functioning of many organs and systems.
The use of antibiotics in renal failure is associated with doubled risk of side and toxic effects.
That is the reason why meticulously modificated dosing of antibiotics eliminating or metabolized by kidney is essential, particularly antibiotics with small therapic wideness and antibiotics which cumulate.
Tetracycline familyWhen used in larger doses, antibiotics in this family can cause jaundice, fever, and fatty liver
Erythromycin familyThese antibiotics can cause damage to the liver via cholestasis (bile retention) and jaundice. The harmful effects usually start to show after 10 to 14 days use and the incidence rate is approximately 5 to 10%. Clinically, patients may experience stomachache, nausea, vomiting, jaundice, and elevation of liver enzymes.
.
Penicillin family.cause the least liver damage and only patients who are allergic may experience some side effects. penicillin family are the most "liver friendly" and safe for chronic hepatitis patients to use.
Guidelines for compromised hepatic functionPotential impairmentExamples of dental drugs eliminatedLab testRangeMargin of safety for dental prescribingHepaticAcetaminophenCodeineDiazepamErythromycinIbuprofenKetoconazoleLidocaineLorazepamPrednisone
AST, ALT, liver transaminases30-40 u/lIf greater than 4 times normal, do not use drugs that are toxic to or metabolized by the liverIf available, some laboratory values may serve as guidelines for prescribing drugs eliminated by the liverGuidelines for compromised renal Potential impairmentExamples of dental drugs eliminatedLab testRangeMargin of safety for dental prescribingRenalAmoxicillinCephalosporinPenicillinTetracyclineGFR (Creatinine Clearance)50 ml/minOne dose q 24 hrsOne dose q 8-12 hoursOne dose q 8 hours
If available, some laboratory values may serve as guidelines for prescribing drugs eliminated by the kidneyIt is important to note most medications prescribed for dental purposes are prescribed for only a short duration and many have a large margin of safety, which reduces the risk of ADRs.
prophylaxisFor decades, the American Heart Association (AHA) recommended that patients with certain heart conditions take antibiotics shortly before dental treatment.
done with the belief prevention of infective endocarditis (IE)
The AHAs latest guidelines were published in its scientific journal, Circulation, in April 2007 AHA recommends that most of these patients no longer need short-term antibiotics as a preventive measure before their dental treatment.
The guidelines are based on a growing body of scientific evidence that shows the risks of taking preventive antibiotics outweigh the benefits for most patients.
Inappropriate use of antibiotics can also lead to the development of drug resistant bacteria.no compelling evidence that taking antibiotics prior to a dental procedure prevents IE in patients who are at risk of developing a heart infection.
Their hearts are already often exposed to bacteria from the mouth, which enter their bloodstream during basic daily activities such as brushing or flossing.
The new guidelines are based on a comprehensive review of published studies that suggests IE is more likely to occur as a result of these everyday activities than from a dental procedure.The guidelines say patients who have taken prophylactic antibiotics routinely in the past but no longer need them include people with:
mitral valve prolapse
rheumatic heart disease
bicuspid valve disease
calcified aortic stenosis
congenital heart conditions such as ventricular septal defect, atrial septal defect and hypertrophic cardiomyopathy.
The new guidelines are aimed at patients who would have the greatest danger of a bad outcome if they developed a heart infection.
Preventive antibiotics prior to a dental procedure are advised for patients with:1. artificial heart valves2. a history of infective endocarditis3. certain specific, serious congenital (present from birth) heart conditions, including unrepaired or incompletely repaired cyanotic congenital heart diseasea completely repaired congenital heart defect with prosthetic material or device, during the first six months after the procedureany repaired congenital heart defect with residual defect at the site or adjacent to the site of a prosthetic patch or a prosthetic device4. a cardiac transplant that develops a problem in a heart valve
Frequency, Nature, Magnitude, and Duration of Bacteremia Associated With a Dental Procedure
Transient bacteremia is common with manipulation of the teeth and periodontal tissues, and there is a wide variation in reported frequencies of bacteremia in patients resulting from dental procedures: Tooth extraction (10% to 100%),Periodontal surgery (36% to 88%),Scaling and root planing (8% to 80%),Rubber dam matrix/wedge placement (9% to 32%),Endodontic procedures (up to 20%)Transient bacteremia also occurs frequently during routine daily activities unrelated to a dental procedure, such as
tooth brushing and flossing (20% to 68%), use of wooden toothpicks (20% to 40%), use of water irrigation devices (7% to 50%),chewing food (7% to 51%).
119conclusionAntibiotics are an important tool in the hands of a clinician when dealing with infections in endodontics
It is extremely important to use them appropriately according to the clinical situation and needs of the patient
Modification of the drug dosage during specific medical condition
REFERENCESEssentails of Medical Pharmacology : KD TRIPATHI, 5 EdnEndodontics John I.Ingle 6th edPathways of pulp Stephen Cohen .9th edPharmacolgy & Pharmacotherapeutics: RS SATOSKAR & SD BHANDARKAR, 13 Edn
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