newer antibiotics - pharmacell€¦ · newer antibiotics. newer antibiotics b-lactams quinolones...
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NEWER ANTIBIOTICS
NEWER ANTIBIOTICS
B-LACTAMS QUINOLONESCEPHALOSPORINS LEVOFLOXACIN
SPARFLOXACINCEFDITOREN GATIFLOXACINCEFEPIME GREPOFLOXACIN CEFEPIROME TRAVOFLOXACIN
CARBAPENEMS MOXIFLOXACINERTAPENEM CLINAFLOXACIN
MACROLIDES OXAZOLIDINONESDIRITHRMYCIN LINEZOLID
STREPTOGRAMINSJOSAMYCIN DALFOPRISTIN
AMINOGLYCOSIDES QUINPRISTIN
ARBIKACIN GLYCO/LIPOPEPTIDESDAPTOMYCINORITAVANICIN
GLYCINCYCLINS TEGICYCLINS
CEPHALOSPORINS• The activity of cephalosporins increases over gram negative organisms
as the generation passes• 4th generation are even resistant to b-lactamases and highely active
against pseudomonas• They act by inhibiting cell wall synthesis• INDICATION DOSAGE :cefditoren at 200-400mg po12hly indicated
for bronchitis, complicated sinusitis,otitis media,uti cefepime at 500-2g iv 8-12hly indicated for empirical therapy in febrile neutropenic patients and ABR gram-ve bacteremia
• ADVERSE EFFECTS:git effects, thrombophlebitis(cfepime), rare ones like hypersensitivity,interstitial nephritis,anemia, leukopenia
• CONTRAINDICATIONS: Decreased dosage in renal failure .cefepirome contra in pregnancy lactating .cefepime is to used with caution in lactating patients
QUINOLONES
• The activity of quinolones increases over gram +ve organisms as the generation increases .4th generation drugs are active against even anaerobic organisms
• INDICATIONS: levofloxacin(250-750mg po od)for sinusitis, bronchitis, pneumonia, uti . Gatifloxacin(400mg po/iv od 7-14days) for LRTI,UTI, gonorrhea .moxifloxacin(400mg po/iv od) for sinusitis,bronchitis ,pneumonia
• ADVERSE EFFECTS :most well tolerated drugs .nasuea ,rashes, cns disturbances .
• INTERACTIONS: increases QT interval• CONTRAINDICATIONS:2nd,3rd generation decrease dosage in renal
failure .4th generation decrease dosage in hepatic failure • Not to used in pregnancy lactating children below 18yrs
GLYCINCYCLINS(TEGICYCLIN)
• Bacteriostatic drug having good activity against gram+ve and gram –ve organisms
• Activity similar to tetracyclins• Inhibits protein synthesis by binding with 30s subunit• INDICATION: complicated skin&intra abdominal infections caused
by susceptable strains• DOSAGE:100mg stat followed by 50mg every 12th hly IV for 5-14days• ADVERSE EFFECTS: git side effects, irritation at injection site
,photosensitivity• INTERACTIONS: decreased elimination of warfarin• CONTRAINDICATIONS: not safe in pregnant lactating and children
below 8 yrs
KETOLIDE(TELITHROMYCIN)
• Telithromycin has broad spectrum of activity against gram +ve bacteria ,active against most macrolide resistant pneumococci, but like erythromycin not active against staph aureus
• INDICATION: for sinusitis, bronchitis , pneumonia• DOSAGE:800mg od daily dosage• ADVERSE EFFECTS: git side effects , vision problems ,
hepatotoxicity, pseudomembrane colitis • INTERACTIONS: inhibitor of cyp3a4• CONTRAINDICATIONS: decreased dosage in hepatic failure, no data
for pregnant, lactating, children
OXAZOLIDINONES(LINEZOLID)
• Outstanding activity against variety of gram positive organisms • Linezolid prevents formation of the 70S ribosome complex• No cross resistance• INDICAT/DOSAGE: at 10mg/kg iv/po for 10-14days is used as
an alternative to vancomycin for MRSA pneumonia/enterococcal meningitis
• Adverse effects: git side effects /oral moniliasis/ taste perverstion thrombocytopenia / myelosupression
• Contraindications: pregnancy/lactation-caution .FDA has approved for treating infections in infants .NO contraindication in renal, hepatic failure
• Interactions: MAO inhibitor
STREPTOGRAMINS(DALFOPRISTIN-QUINPRISTIN)
• Good activity against MDR gram +ve organisms except enterococcal feacalis active against gram –ve URT pathogens
• Inhibits protein synthesis by binding to 50s ribosome • Both are static drugs individually but cidal when used in combination,• StreA:streB—30%:70%• INDICATION: VRSA ORSA VR enterococcal feacium infections• DOSAGE: 7.5mg/kg IV ever 8-12hly for 7das• ADVERSE EFECTS: thrombophlebitis, arthralgias ,myalgias • INTERACTIONS: inhibits cyt p3a4• CONTRAINDICATIONS: hepatic failure , not safe in children
pregnant ,lactating women
GLYCO/LIPOPEPTIDE(DAPTOMCIN)
• Bactericidal activity against wide variety of gran +ve bacteria including enterococi,staphylococci,streptococci that are even resistent to methicillin& vancomycin
• Daptomycin bind to bacterial mambrane causes rapid depolarisation of membrane potential resulting in inhibition of dna rna protein synthesis
• INDICATION: at dose of 4mg/kg iv od is approved for treatment of complicated skin infections
• ADVERSE EFFECTS: git side effects , increased LFTS ,increased CPK with or with out myopathy
• CONTRAINDICATIONS: renal failure ,inpregnant and lactitating no data
CARBAPENEMS(ERTAPENEM)
• Effective against gram –ve bacteria and anaerobic bacteria • It inhibits cell wall synthesis• INDICATION: indicated only for community acquired
infections because of its lack activity against pseudomonas• DOSAGE:1gm iv once aday• ADVERS EFFECTS: diarrhoea• seizeures(older,renal failure,cns
pathology)• pseudomembrane colitis• CONTRAINDICATIONS: renal failure, no data in
pregnant lactating and children
Why?
•Increasing resistance patterns among both community and hospital acquire infections•Judicious use will prevent resistance strains to emerge
INDICATIONS
1.Clinical scenario
2.Organisms common in that scenario
3.Antibiotic resistance patterns
4.Pharmacokinetics of the drug
5.Clinical trials
Community infections
•Pneumonia
•Meningitis
•Osteomyelitis
COMMUNITY ACQUIRED PNEUMONIA
Core pathogens
•Streptococcus pneumonia•Mycoplasma pneumoniae (during epidemics)•Haemophilus influenzae•Staphylococcus aureus•Chlamydia pneumonia•Legionella pneumophila
Pencillin resistance is a major problem in these casesSo the drug used should take into account of the organism, risk factors for atypical organisms,anti biotic resistance
With no risk factors
• Patient can be treated with
• Ketolides(telithromycin)
• New extended spectrum fluroquinolones
• Ertapenem if there is e/o of vancomycin resistance
Fluoro quinolene should not be used in patients with Rhinitis,sinusitis,Pahryngitis unless there is evidence of pneumonia……………ACP recommendation.
Meningitis
Mc organisms
• Strep.pneumoniae• H.influenza• Neisseria meningitidis• Streptococcus agalactiae• Listeria monocytogenes
Pencillin resistance is also major problem
So empirical therapy is started with 3rd generation cephalosporinsBut if risk factors are present for listeria ampicillin with gantamycin should be used as empirical therapy
Cephalosporins are ineffective
AFTER GRAM STAIN AND CULTURE
EMPIRICAL THERAPY CAN BE CHANGED TO
MORE SPECIFIC THERAPY
In adults penetration of vancomycin is not good especially if dexamethasone is being used So in such cases ceftriaxone plus rifampcin is used
Newer antibiotic LINEZOLIDE irrespective of dexamethasone therapy reaches high concenteration in CSF fluid so can be used in stead of ceftriaxone +rifampcin
Osteomyleitis
Acute haematogenous infection : Staph.aureus
Secondary to contagious focus of infectionPolymicrobial: staphylococci, streptococci, enteric organisms, and anaerobic bacteria.
P. aeruginosa is frequently associated with puncture wounds of the foot (especially by a nail through a sneaker)
Penicillin-resistant, methicillin-sensitive (MSSA ) --- ceftriaxone, 1 g IV q24h
Methicillin-resistant (MRSA ) --- Vancomycin
Vancomycin alone always not effective in such cases. Rifampcin can be added New antibiotics like daptomycin is effective
osteomyelitis due to Enterobacteriaceae ---- Extended spectrum β-lactam antibiotics fluoroquinolone
Hospital acquired infections
Most common are
•UTI
•Pneumonia
•Surgical site infections
UTI
Mc organisms are E.coli, enterobacteraceaenterococcipseudomonas
Risk factors for uti include catheterization,instrumentation,diabetesMost are resistant to tmp-smx,amoxiciliinIn such cases
Fluroquinolones,extende spectrum b-lactams likeTicarcillinCarbapenem—(Imipenem)
Fosfomycin has been recently approved for uncomplicated UTI
Hospital acquired pneumonia
Most common organisms are ;•Pneumococcus•Staph areus•Enterobacteriacea•Pseudomonas•Anaerobes
Many are resistant to pencillin,Enterobacteriacea are resistant to cephalosporinsPseudomonas to cephalosporins,pencillin
HAP is classified into 3 types based on risk factors and severity of pneumoniaAnd the time of development of pneumonia(<5days >5days)
1.Moderate to MILD ,early onset, no risk factors treated like CAPRx: 3rd generation cephalosporins or fluroquinolones
2.Moderate to severe,early onset, if risk factor presentadditional antibiotic is added
If risk factors …
Anaerobes…… Clindamycin
Pseudomonas Extended spectrum Blactam+aminoglycoside
Staph.aureus Vancomycin,linezolid,ortitavanicin
Entero bacteriacea cephamycins
3.Severe H.A.P Use amino glycoside with carbapenems or extended blactams
Surgical site infections
Most commonG+cocci. Staphyloccoccus aureus, Staphylococcus
epidermidis,
Enterococcus faecalis and Escherichia coli, the latter two of which are common pathogens after clean-contaminated surgery.
Antibiotic chosen should be active against Staph1 generation cephalosporins CEFAZOLIN commonly usedThe antibiotic should be given within two hrs of sugery
Single dose prophylaxis is enough
Unless if the patient is undergoing transplant surgery(48 hrs)
Immunocompromised Individuals
Patients with neutropenia
neutropenia is common in hematological malignancies:Such patients predisposed to both gram +Coagulase – staphStre. viridans and g- infectionsEspecially to pseudomonasPatient is said to have low risk neutropenia ifFACTORS ASSOCIATED WITH A LOW RISK OF SEVERE COMPLICATIONS•Malignancy in remission•Absence of co-morbidities (chronic lung disease, diabetes mellitus, congestive heart failure, hemorrhage, liver disease, renal disease)•Absence of vomiting, diarrhea, dehydrationOutpatient status•Absolute monocyte count =100 cells/mm3•Anticipated duration of neutropenia <7–10 days•Normal chest radiograph•Peak temperature <102.2°F (39.0°C)•Absence of shivering•Does not appear ill•Absence of neurologic or mental alterations•Absence of abdominal pain•Absence of intravenous catheter site infection•Absence of septic complications (e.g. severe sepsis, septic shock, hypoxia, pneumonia or other deep organ infection)
In neutro penia IV anti biotics are usedThe anti biotic Should be BACTERICIDAL:,
NON TOXICBROAD SPECTRUM
PREVIOUSLY the initial treatment used to beExtended spectrum pencillin/Antipseudomonal cephalosporin+Aminoglycoside
(Toxic regimen)EORTC-IATG trial showed that mono therapy with ceftriaxone+amikacin is as effective as thrice daily regemen of ceftazidime+amikacinSo now neutropenia patients are treatedMONOTHERAPY 1Carbapenems
2.extended spectrum b lactam/blactamase inhibitor3.3rd and 4th gen. Cephalosporins
And amino glycoside should be added if there is septic shock,severe sepsis,and pseudomonas infection is suspectedAdd vancomycin or linezolid or ortivanacin if sepsis shock and evidence or sucpicion of catheter based infectionIn low risk patients oral fluroquinolones can be give and are effective
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