Approach to pediatric Antibiotics

Approach to pediatric Antibiotics Gassem Gohal FAAP FRCPC Assistant professor of Pediatrics

objectives To be familiar with common pediatric antibiotics o Classification o Action o Adverse effect To discus common outpatient pediatric infections

Antibiotic choice How do you choose the proper antibiotic It depends on: causative organism Site of infection Host susceptibility narrow spectrum

Sulfonamides Penicillins Cephalosporins Tetracyclines Aminoglycosides Quinolones Macrolides Antibiotics classification:

Type of therapy Empiric therapy: treatment of an infection before specific culture Prophylactic therapy: treatment with antibiotics to prevent an infection Definitive therapy

How Antibiotics Work Inhibit cell wall formation - Penicillin Block protein formation - Macrolides, Aminoglycosides Interfere with DNA formation - Nalidixic acid Prevent folic acid synthesis - Sulfonamides

Natural penicillins PenG, PenV Aminopenicillins Ampicillin, Amoxicillin Anti-Staph penicillins Oxacillin, Dicloxacillin Anti-Pseudomonal Ticarcillin Piperacillin Penicillins

Penicillin Available PO, IM, IV (dosed in units) Drug of Choice, Group A Strep, N. meningitidis, Adverse Reactions skin rash serum sickness Hemolytic anemia, pancytopenia, neutropenia

Ampicillin Amoxicillin Amp (IV, PO) Amox (PO) Spectrum: PenG + H. flu and some E. coli, Listeria monocytogenes and, Enterococcus

Penicillin resistance Bacteria produce enzymes capable of destroying penicillin. beta-lactamases

Penicillin resistance Chemicals to inhibit beta-lactamases clavulanic acid tazobactam Sulbactam amoxicillin + clavulanic acid = Augmentin ticarcillin + clavulanic acid = Timentin piperacillin + tazobactam = Tazocin

Cephalosporins 1 st Generation Cephalexin, Cefazolin 2 nd Generation Cefoxitin, Cefuroxime, 3 rd Generation Cefotaxime, Ceftriaxone, Ceftazidime 4 th Generation Cefepime

Cephalosporins 1 st Generation Gram (+) 2 nd Generation 3 rd Generation Decreasing Gram (+) and Increasing Gram (-) Gram (-), but also some GPC 4 th Generation Gram (+) and Gram (-)

1 st Generation: Cefazolin Good for Gram (+) bugs Osteomyelitis Strep Group A Staph MSSA & MSSE Poorer choices: E. coli (50% resistant), Klebsiella

2 nd Generations: Cefuroxime Much better gram-negative coverage (except Pseudomonas) Good: Gram (+) (esp. Strep pneumoniae), Groups A&B, MSSA H. influenzae but not meningitis!? E. coli and Klebsiella

2 nd Generations: Cefuroxime (Zinacef ) Much better gram-negative coverage (except Pseudomonas) Good: Gram (+) (esp. Strep pneumoniae), Groups A&B, MSSA H. influenzae but not meningitis!? why E. coli and Klebsiella

3 rd Generations Ceftriaxone, Cefotaxime, Ceftazidime Ceftazidime :Pseudomonas, Ceftriaxone and Cefotaxime very good against S. pneumoniae (use with vancomycin if treating meningitis) and H. influenzae; Donʼt use for Staph aureus Drugs of choice for most CNS infections

Aminoglycosides Gentamicin, Tobramycin, Amikacin Aerobic, gram-negatives only Good choice for Pseudomonas infections! Use for Synergy with Beta-Lactams for Enterococcus, and Group B Strep Toxic to otovestibular system and kidneys

QUINOLONES Ciprofloxacin Don t use in those under 18 years of age, except approved as 2nd line therapy for urinary tract infections in children. Why?

Vancomycin MRSA, MRSE, and ampicillin-resistant Enterococcus S. pneumoniae meningitis especially if resistant to beta-lactam antibiotics NOT for gram-negatives Red Man Syndrome : ***Resistance is quickly emerging in Enterococcus (vancomycin-resistant Enterococcus VRE)

Macrolides: Erythromycin, Clarithromycin, Azithromycin Mycoplasma; Chlamydia;,Staph and Strep Azithromycin adds H. influenzae coverage Erythromycin and clarithromycin lots of drug interactions. Azithromycin doesn t have same profile.

Macrolides Erythromycin, Clarithromycin, Azithromycin Mycoplasma; Chlamydia;,Staph and Strep Azithromycin adds H. influenzae coverage Erythromycin and clarithromycin lots of drug interactions. GIVE ME Example Azithromycin doesn t have same profile.

Some common pediatric infection

Acute bacterial sinusitis Dx: Inflammation of the mucosal lining Usually viral URI ( resolve) Bacterial ( suspect if >10 days of URI) URI, allergic rhini1s predisposing factor

Acute bacterial sinusitis First line therapy is amoxicillin 45-90 mg/kg/day divided bid. Severe symptoms is high dose augmentin (90 mg/kg/day amox., 6.4 mg/kg/day clavulanic acid) divided bid. Allergies to penicillin, first line therapy is azithromycin 10 mg/kg kg x 1 day, followed by 5 mg/kg x 4 day,

Acute otitis media Dx of OM fluid in the middle ear plus acute signs of illness signs or symptoms of middle ear inflammation, including bulging

Acute otitis media How should treats? Less than 2 y = treat More than 2 y, treat if toxic, or not normal host

AAP guideline Rx of OM

Group A Strep Pharyngitis First line therapy: Penicillin V is the recommended treatment. Alternative therapy: For patients allergic to Penicillin, use erythromycin. Length of treatment: Ten days of treatment are necessary to prevent the development of rheumatic fever.

Group A Strep Pharyngitis How to differentiate viral from GAS Pharyngitis First line therapy: Penicillin V is the recommended treatment. Alternative therapy: For patients allergic to Penicillin, use erythromycin. Length of treatment: Ten days of treatment are necessary to prevent the development of rheumatic fever.

Community acquired pneumonia 0-3 weeks GBS, Gram rods, CMV 3 weeks 3 months Chlamydia trachomatis, Strep pneumo, RSV, paraflu 4 months 4 yrs Viruses most common, then strep pneumo, than mycoplasma pneumoniae (in older patients in age range 5 yrs 15 yrs Mycoplasma pneumoniae, Chlamydia pneumoniae, Strep pneumo

Community acquired pneumonia-rx 0-3 weeks, Patient must be admitted 3 weeks 3 months Patient admitted if febrile. If afebrile, azithromycin, or erythromycin are recommended first line therapies. If the patient has a well defined, lobar infiltrate on CXR, however, amoxicillin should be used, either in combination with a macrolide or alone. 4 months 4 years Amoxicillin 5 years-15 years Azithromycin, or erythromycin

Home work Review two approach to child with fever ( less than 3 months, 3 month to 3 years) Get an answer for all whys in this lecture plus what I asked you to check

Take Home massage Use of antibiotics based on knowledge of disease, host, character of antibiotics entity, not just by remembering these lecture Go back, check and read, things get forgotten

References Check the website www.pedsjazan.wordpress.com http://pediatrics.uchicago.edu/chiefs/cliniccurriculum/documents/jflabx 4commonpedsinfxn.pdf http://www.medstudy.com/pedsantibiotics/pediatrics_antibiotics.html