Antibiotics Review _ __________________________________________________________________________
THE MACROLIDES
Agent
Adult Dosing Range
Pediatric Dosing Range
Route
Common Side Effects
Comments
Azithromycin
PO: 250–600 mg/ day, or 1–2 g/day IV: 250–500 mg/ day 250–500 mg every 12 hrs, or 1 g/day extended-release formulation for 7 to 14 days Base: 250–500 mg PO every 6 to 12 hrs Max: 4 g/day Ethylsuccinate: 400–800 mg PO every 6 to 12 hrs Max: 4 g/day Lactobionate: 15–20 mg/kg/day IV in 4 divided doses, or 0.5–1 g IV every 6 hrs, or continuous infusion over 24 hrs (Max: 4 g/day)
PO: 5–12 mg/kg/day Max: 500 mg/day Otitis media: 30 mg/ kg as single dose (not to exceed 1,500 mg) >6 mos of age: 7.5 mg/kg every 12 hrs
PO, IV, ophthal- mic drops
GI upset
One dose of 1 g given PO can be used for non- GC urethritis/cervicitis. Interaction with pimozide/ cyclosporine. Inhibits liver CYP 450 enzyme 3A4, resulting in multiple significant drug interactions. Special dosing combined with omeprazole and amoxicillin or lansoprazole and amoxicillin is one regimen used for H. pylori treatment. Inhibits liver CYP 450 enzymes 3A4 and 1A2, resulting in multiple significant drug interactions.
Clarithromycin
PO GI upset, metallic taste
Erythromycin
Base: 30–50 mg/ kg/day PO in 2 to 4 divided doses Max: 2 g/day
PO, IV, ophthal- mic solution, topical ointment, gel, or pad
GI intolerance (common), phlebitis at IV infusion site
Ethylsuccinate: 30–50 mg/kg/day PO in 2 to 4 divided doses Max: 4 g/day Stearate: 30–50 mg/ kg/day PO in 2 to 4
divided doses Max: 2 g/day
Lactobionate: 15–50 mg/kg/day IV in 4
divided doses Max: 4 g/day
Fidaxomicin
PO Nausea,
Used for treatment of diarrhea due to C. difficile
200 mg twice daily for 10 days
Not studied in pediatric patients
abdominal pain
Prescribing information is given for comparison purposes only. The higher dosage ranges reflect dosages for more severe infections. Please consult the manufacturer’s package insert for the antibiotic for complete prescribing information, maximum dosages, and indications. Non-GC = nongonococcal infection. Source: [6; 16] Table 5
PHARMACOKINETICS Erythromycin has a wide spectrum of activity. Gram-positive bacteria that are usually susceptible to erythromycin include the Streptococcus species. Erythromycin is a second-line agent for gram-negative bacteria, such as H. influenzae (when used concomitantly with sulfonamides) and M. catarrhalis . Mac- rolides are particularly useful for their coverage of atypical bacteria, such as Mycoplasma and Chlamydia . Some spirochetes and mycobacteria are also susceptible to the macrolides. These drugs are indicated for upper respiratory tract infections, such as sinusitis, otitis media, pharyngitis, and bronchitis. They are also useful in the treatment of pertussis, Legionnaires disease, and diphtheria.
The gene for this mechanism is transferred on plasmids between bacteria. Mutations of the 50S ribosomal receptor site may also develop, preventing binding of the erythromycin [101]. Lastly, bacterial enzymes have been described that may deactivate erythromycin [102]. It is likely that this form of resistance is also transferred on plasmids. Many strains of H. influenzae are resistant to erythromycin alone but are susceptible to a combination with a sulfonamide [103]. Erythromycin ethylsuccinate and sulfisoxazole are manufac- tured as suspensions for use in treating acute otitis media in children older than 2 months of age [6]. They are useful for targeting H. influenzae , one of the common pathogens in otitis media in this age group.
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MDTX2026
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