Saturday, December 03, 2005

Aminopenicillins

Aminopenicillins

(Ampicillin, Amoxicillin, Augmentin, Unasyn)

See Also

Penicillin

Preparations: Amoxicillin and Ampicillin
Ampicillin
Child: 50-200 mg/kg/day IV divided qid

Amoxicillin
Adult: 875 mg PO bid
Child: 45 mg/kg/day divided PO bid

Preparations: Added Beta-lactamase resistance

Ampicillin Sulbactam (Unasyn)
Adult: 1.5-3 grams IV every 6 hours

Amoxicillin Clavulanate (Augmentin)
Adult: 875 mg PO bid
Child: 45 mg/kg/day divided PO bid

Mechanisms of action

Same as for Natural Penicillins
Penetrates outer membrane of some
Gram Negatives
Clavulanic acid and sulbactam bind Beta-lactamases

Pharmacokinetics

Keep Augmentin suspension refrigerated
Clavulanate suspension breaks down at room temperature
Turns brown with breakdown
Loses 90% of potency after 2 days at room temperature

Bacterial Resistance Mechanisms Overcome

Beta-lactamase Production
Alteration of
Penicillin binding protein
Activity Spectrum

General
Gram Positive Cocci
Gram Negative Rods
Spirochetes (e.g. Treponema pallidum)

Conditions
Otitis Media
Sinusitis
CNS Infection
Urinary Tract Infection
Infectious Enteritis
Borrelia Burgdorferi (Lyme Disease)
Helicobacter Pylori

Adverse effects

Similar to Natural Penicillins
Maculopapular rash

Diarrhea (modifications can decrease stools to 12%)
Dose exactly by kilogram for children
Avoid food before dose
Consider eating yogurt with each dose

Family Practice Notebook

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