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Azithromycin (Zithromax)
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Basic information
- Generic name: Azithromycin
- Brand/Trade names: Zithromax
- Dosages:
Tablets: 250 mg, 500 mg, 600 mg (as dihydrate)
Powder for injection, lyophilized: 500 mg
Powder for oral suspension: 100 mg per 5 mL; 200 mg per 5 mL;
1 g/packet (as dihydrate)
- Pharmacologic category: Macrolide antibiotic
- FDA approved: June 12, 1996
- Habit forming? No
- Pregnancy risk factor: B
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Medical uses
Azithromycin (Zithromax) is a powerful broad spectrum semi-synthetic
macrolide antibiotic. It is the first representative of a new
subclass of macrolides called azalides. Azithromycin is similar
in structure to erythromycin.
Azithromycin (Zithromax) is used to treat the following mild
to moderate infections:
- Lower Respiratory Tract infections: acute bacterial
exacerbations of chronic obstructive pulmonary disease; community-acquired
pneumonia of mild severity.
- Upper Respiratory Tract infections: pharyngitis, tonsillitis,
otitis media, sinusitis
- Skin and Skin Structure infections: uncomplicated skin
and skin structure infections. Abscesses usually require surgical
drainage.
- Chancroid (genital ulcer disease in men): due to the
small number of women included in clinical trials, the efficacy
of azithromycin in the treatment of chancroid in women has not
been established.
- Sexually Transmitted Diseases: urethritis and cervicitis
due to Chlamydia trachomatis or Neisseria gonorrhoeae.
- Mycobacterial Infections.
Azithromycin rarely causes side effects. Gastrointestinal disturbances
(flatulence, nausea, vomiting, diarrhea and abdominal pain) and
a rash may occur. Transient moderate elevations of hepatic enzymes
values, neutropenia and rarely neutrophilia and eosinophilia have
been observed.
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Pharmacological characteristics
- Elimination half-life: The t 1/2 is approximately 68
h.
- Metabolism: Hepatic
- Excretion: Excreted primarily in the bile, predominantly
as unchanged drug. Approximately 6% is excreted in urine as
unchanged drug (oral); approximately 11% is excreted in the
urine after first dose and 14% after fifth dose (IV).
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Benefits
- Targeted activity from the site of infection. Due to
the high concentration in phagocytes, azithromycin is actively
transported to the site of infection.
- Active against most bacteria causing respiratory trect
infections.
- Low potential for drug interactions. Due to the fact
that azithromyci is not metabolysed through P 450 system, it
does not effect metabolysm of other drugs. Other macrolides
are frequently involved in drug to drug interactions.
- Easy to use - very convenient dosing. Simple dosing
in antibiotic therapy decreases possibility of bad compliance.
Azithromycin's half-life allows a large single dose to be administered
and yet maintain bacteriostatic levels in the infected tissue
for several days. Good compliance improoves clinical outcome,
decreases possibility of selection for resistance and decreases
need for subsequent represcribing of antibiotics.
- Excellent safety. Azithromycin rarely causes side effects.
- Effective treatment for chlamydia during pregnancy. Azithromycin
has been shown to be safe in pregnant women and is recommended
as the treatment of choice for chlamydia during pregnancy.
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Unlabeled uses
- Dental infections.
Azithromycin is used is in patients who are allergic to penicillins
and who also are at risk of developing bacterial endocarditis
(a serious and potentially fatal heart infection) following
dental procedures likely to induce mucosal or gingival bleeding.
Such procedures include dental extractions, periodontal surgery,
professional cleanings, orthodontic band (not bracket) placement
and some other procedures.
- Acne
Azithromycin may be safe and effective antibiotic for the treatment
of acne. Azithromycin (250 mg dose three times a week) produces
about 80% reduction in the inflammatory acne lesions2.
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Mechanism of action
By inhibition of protein synthesis it effects the ability of
bacteria to replicate and grow. Antimicrobial spectrum of Sumamed
includes different Gram - positive, Gram - negative, anaerobic,
intracellular and atypical microorganisms. Because of the transport
with white blood cells, Sumamed possesses a unique property -
targeted activity at the site of infection. In infected tissues,
Sumamed achieves high and sustained therapeutic concentrations
that last five to seven days after the last dose. Because of that,
administration of Sumamed is simple and short.
Inhibits RNA-dependent protein synthesis at the chain elongation
step; binds to the 50S ribosomal subunit resulting in blockage
of transpeptidation
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Azithromycin (Zithromax) Discussion Boards &
Forums
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References
- 1. U.S. Food and Drug Administration.
Azithromycin (Zithromax) U.S. Prescribing Information. Available
at (PDF format): Prescribing
Information
- 2. Fernandez-Obregon AC. Azithromycin for
the treatment of acne. Int J Dermatol. 2000 Jan;39(1):45-50.
PubMed
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Interesting Azithromycin facts
- On 20 August 2000 in Washington D.C., USA, the American Chemical
Society (ACS), a non-profit association of American chemists and
chemical engineers and the largest association of scientists in
the world organised the "Heroes of Chemistry 2000" ceremony. For
their discovery of azithromycin, PLIVA scientists Slobodan Dokic
and Gabrijela Kobrehel were named "Heroes of Chemistry", together
with representatives from US-based Pfizer which had also contributed
to the success of azithromycin.
- Zithromax offers excellent tolerability, with a low incidence
of adverse events. Zithromax is designated pregnancy category B.
- Zithromax is a good choice for children who are allergic to penicillin.
- Zithromax has to be one of the most convenient antibiotics. The
fact that you can also take just a three or one day course of Zithromax
makes it particularly popular with parents of children who don't
like to take medicine.
- The 250 mg tablets are often dispensed in packages of six and
commonly referred to as a "Z-Pak," whereas the 500 mg tablets are
commonly available commercially in a pack of three tablets, or "Tri-Pak,"
intended as a three-day treatment.
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