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
Antibiotics classification:
• Sulfonamides
• Penicillins
• Cephalosporins
• Tetracyclines
• Aminoglycosides
• Quinolones
• Macrolides
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
Penicillins
– Natural penicillins
PenG, PenV
– Aminopenicillins Ampicillin, Amoxicillin
– Anti-Staph penicillins Oxacillin, Dicloxacillin
– Anti-Pseudomonal Ticarcillin
Piperacillin
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
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
– 1st Generation
Cephalexin, Cefazolin
– 2nd Generation Cefoxitin, Cefuroxime,
– 3rd Generation Cefotaxime, Ceftriaxone, Ceftazidime
– 4th Generation Cefepime
Cephalosporins
1st Generation Gram (+)
2nd Generation Decreasing Gram (+) and Increasing Gram (-)
3rd Generation Gram (-), but also some GPC
4th Generation Gram (+) and Gram (-)
1st Generation:
Cefazolin
•Good for Gram (+) bugs
•Osteomyelitis
•Strep– Group A
•Staph– MSSA & MSSE
•Poorer choices: E. coli (50% resistant), Klebsiella
2nd 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
•
2nd 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
•
3rd 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
3rd 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
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)
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
AAP guideline Rx of OM
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/JFLAbx4commonpedsinfxn.pdf
• http://www.medstudy.com/PedsAntibiotics/Pediatrics_Antibiotics.html