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Extended Spectrum Macrolide
Aka: Extended Spectrum Macrolide, Azithromycin, Zithromax, Clarithromycin, Biaxin, Telithromycin, Ketek- See also
- Pharmacokinetics: Half Life
- Clarithromycin: 5 hours
- Telithromycin: 10 hours
- Azithromycin: 68 hours
- Precautions
- Increasing Macrolide resistance for most indications (see below)
- QT Prolongation with Azithromycin (see below)
- Calcium Channel Blocker interaction with Clarithromycin (see below)
- Macrolides in general (including Azithromycin) may increase heart defects with first trimester exposure of 5-7 days
- Previously only Clarithromycin was considered a potential Teratogen (Cleft Lip association)
- Fan (2020) BMJ 368: m331 +PMID:32075790 [PubMed]
- Dosing: Azithromycin (Zithromax)
- Directions
- Take more than 1 hour before or 2 hours after food
- Adult
- Day 1: 500 mg PO qd
- Day 2 to 5: 250 mg PO qd
- Child
- Day 1: 10 mg/kg PO qd (maximum: 500 mg)
- Day 2 to 5: 5 mg/kg PO qd (maximum: 250 mg)
- Infant under age 6 months
- 10 mg/kg/day for 5 days
- New preparations
- ZMax 2 grams orally x1 dose (Available in 2005)
- For uncomplicated Community Acquired Pneumonia
- Vomiting >1 hour after dose - no additional med
- Use within 12 hours of reconstituting
- References
- (2005) Prescribers Letter 12(8):44
- ZMax 2 grams orally x1 dose (Available in 2005)
- Directions
- Dosing: Clarithromycin (Biaxin)
- May take with or without food
- Adult: 250 to 500 mg PO bid
- Child: 7.5 mg/kg PO bid
- Dosing: Telithromycin
- Adult: 800 mg PO daily
- Course
- Acute Exacerbation of Chronic Bronchitis: 5 days
- Acute Sinusitis: 5 days
- Community Acquired Pneumonia: 7 days
- Adverse Effects
- Class
- Less Nausea and Vomiting than with Erythromycin
- QT Prolongation (see below)
- Three fold increased risk of Sudden Cardiac Death while on Azithromycin
- Ray (2013) N Engl J Med 366(20): 1881-90 [PubMed]
- Clarithromycin
- Dysgeusia or distorted taste (20%)
- Calcium Channel BlockerDrug Interaction (see below)
- Increased cardiovascular deaths
- Observation in some studies as of 2018, but needs confirmation
- Inghammer (2017) Am J Epidemiol +PMID:29155931 [PubMed]
- Svanström (2014) BMJ 349:g4930 +PMID:25139799 [PubMed]
- Class
-
Drug Interactions: Clarithromycin
- Calcium Channel Blockers
- Clarithromycin increases Calcium Channel Blocker levels via CYP3A4 inhibition
- Highest risk with Dihydropyridine Calcium Channel Blockers (Nifedipine, Felodipine)
- Highest risk in age over 65 years old
- Provokes Hypotension and Bradycardia
- Risk of Acute Kidney Injury (often requiring hospitalization)
- Number needed to harm: 1 in 465 for over age 65 years
- References
- Calcium Channel Blockers
- Indications: Major indications for broad spectrum Macrolides
- Single dose Chlamydia trachomatis treatment
- Respiratory infections
- Otitis Media (Azithromycin)
- Not recommended due to increased resistance rates
- Community Acquired Pneumonia
- Limit to suspected Mycoplasma pneumonia or Legionella pneumonia
- Macrolide resistant pneumococcus is common
- Consider Doxycycline as alternative
- Acute Sinusitis (Azithromycin)
- Not recommended due to growing resistance rates
- Streptococcal Pharyngitis
- Macrolides are only indicated in significant allergy to beta-lactams
- Non-tuberculous Mycobacterial infections
- Helicobacter infections
- Otitis Media (Azithromycin)
- References
- (2013) Presc Lett 20(8): 44
- Contraindications
- Telithromycin (Ketek) may cause repiratory failure in Myasthenia Gravis (FDA Black Box Warning)
- Preparations: Activity Spectrum
- Macrolide resistance is increasing
- Resistance to one Macrolide is resistance to all
- Spectrum includes organisms covered by Erythromycin
- Clarithromycin
- Azithromycin
- HaemophilusInfluenzae
- Moraxella catarrhalis
- Toxoplasmosis gondii
- Mycobacterium Avium Complex (Clarithromycin better)
- Borrelia Burgdorferi
- Telithromycin
- Avoid in patients with Myasthenia Gravis due to risk of Respiratory Failure (FDA Black Box Warning)
- Similar to other Extended Spectrum Macrolides
- Appears to have greater activity for pneumococcus
- May be used in place of other broad spectrum agents
- Augmentin
- Extended spectrum Fluoroquinolones
- References
- Macrolide resistance is increasing