Azcotil

Azithromycin dihydrate.

Each Film-coated tablet contains: Azithromycin (as dihydrate) 250 mg.
Each Film-coated tablet contains: Azithromycin (as dihydrate) 500 mg.
Azithromycin is a nitrogen-containing macrolide or azalide with actions and uses similar to those of erythromycin. Azithromycin is derived from erythromycin; however, it differs chemically from erythromycin in that a methyl-substituted nitrogen atom is incorporated atom is incorporated into the lactone ring.

Azithromycin is less active than erythromycin against streptococci and staphylococci, but has greater activity than erythromycin in vitro against some Gram-negative pathogens such as Haemophilus influenza and Moraxella catarrhalis (Branhamella catarrhalis), as well as having activity against some of the Enterobacteriaceae such as Escherichia coli and Salmonella and Shigella spp. Azithromycin is also more active than erythromycin against Chlamydia trachomatis and some opportunistic mycobacteria, including Mycobacterium avium complex. It has activity against the protozoa Toxoplasma gondii and Plasmodium falciparum.
Strains of Streptococcus pneumonia and other penicillin-resistant strains have been observed to exhibit resistance to azithromycin.
Pharmacology: Pharmacodynamics: Azithromycin is an azalide, a sub-class of the macrolide antibiotics. By binding to the 50S-ribosomal sub-unit, azithromycin avoids the translocation of peptide chains from one side of the ribosome to the other. As a consequence of this, RNA-dependent protein synthesis in sensitive organisms is prevented.
Resistance to azithromycin may be inherent or acquired. There are three main mechanisms of resistance in bacteria: target site alteration, alteration in antibiotic transport and modification of the antibiotic.
Complete cross resistance exists among Streptococcus pneumoniae, beta-haemolytic streptococcus of group A, Enterococcus faecalis and Staphylococcus aureus, including methicillin resistant S. aureus (MRSA) to erythromycin, azithromycin, other macrolides and lincosamides.
Pharmacokinetics: Azithromycin given orally is about 40% bioavailable. Peak plasma concentrations are achieved 2-3 hours after a dose, but azithromycin is extensively distributed to the tissues, and tissue concentrations subsequently remain much higher than those in the blood; in contrast to most other antibacterials, plasma concentrations are therefore of little value as a guide to efficacy. High concentrations are taken up into white blood cells. There is little diffusion into the CSF when the meninges are not inflamed. Small amounts of azithromycin are demethylated in the liver, and it is excreted in bile as unchanged drug and metabolites. About 6% of an oral dose (representing about 20% of the amount in the systemic circulation) is excreted in the urine. The terminal elimination half-life is about 68 hours.

Azithromycin is indicated for the treatment of patients with mild to moderate infections (pneumonia) caused by susceptible strains of the designated microorganisms in the specific conditions listed as follows: Acute bacterial exacerbations of chronic obstructive pulmonary disease due to Haemophilus influenzae, Moraxella catarrhalis or Streptococcus pneumoniae.
Acute bacterial sinusitis due to Haemophilus influenzae, Moraxella catarrhalis or Streptococcus pneumoniae.
Community-acquired pneumonia due to Chlamydia pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae or Streptococcus pneumoniae in patients appropriate for oral therapy.
NOTE: Azithromycin should not be used in patients with pneumonia who are judged to be inappropriate for oral therapy because of moderate to severe illness or risk factors such as any of the following: patients with cystic fibrosis, patients with nosocomially acquired infections, patients with known or suspected bacteremia, patients requiring hospitalization, elderly or debilitated patients, or patients with significant underlying health problems that may compromise their ability to respond to their illness (including immunodeficiency or functional asplenia).
Pharyngitis/tonsillitis caused by Streptococcus pyogenes as an alternative to first-line therapy in individuals who cannot use first-line therapy.
Uncomplicated skin and skin structure infections due to Staphylococcus aureus, Streptococcus pyogenes, or Streptococcus agalactiae. Abscesses usually require surgical drainage. Urethritis and cervicitis due to Chlamydia trachomatis or Neisseria gonorrhoeae.
Genital ulcer disease in men due to Haemophilus ducreyi (chancroid). 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.
Azithromycin, at the recommended dose, should not be relied upon to treat syphilis. Antimicrobial agents used in high doses for short periods of time to treat non-gonococcal urethritis may mask or delay the symptoms of incubating syphilis. All patients with sexually-transmitted urethritis or cervicitis should have a serologic test for syphilis and appropriate cultures for gonorrhea performed at the time of diagnosis. Appropriate antimicrobial therapy and follow-up tests for these diseases should be initiated if infection is confirmed.

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Similar effects noted on regular doses. Adverse events experienced in higher than recommended dose were similar effects noted on regular doses. The typical symptoms of an overdose include reversible loss of hearing, severe nausea, vomiting and diarrhea.

Azithromycin is contraindicated in patients with known hypersensitivity to azithromycin, erythromycin, any macrolide or ketolide antibiotic.

Because azithromycin is principally eliminated via the liver, caution should be exercised when azithromycin is administered to patients with impaired hepatic function. Due to the limited data in subjects with GFR < 10 mL/min, caution should be exercised when prescribing azithromycin in these patients.
Prolonged cardiac repolarization and QT interval, imparting a risk of developing cardiac arrhythmia and torsades de pointes, have been seen in treatment with other macrolides. A similar effect with azithromycin cannot be completely ruled out in patients at increased risk for prolonged cardiac repolarization.
Carcinogenesis, Mutagenesis, Impairment of Fertility: Long-term studies in animals have not been performed to evaluate carcinogenic potential. Azithromycin has shown no mutagenic potential in standard laboratory tests: mouse lymphoma assay, human lymphocyte clastogenic assay, and mouse bone marrow clastogenic assay. No evidence of impaired fertility due to azithromycin was found.
Use in the Elderly: Pharmacokinetic parameters in older volunteers (65-85 years old) were similar to those in younger volunteers (18-40 years old) for the 5-day therapeutic regimen. Dosage adjustment does not appear to be necessary for older patients with normal renal and hepatic function receiving treatment with this dosage regimen.

Pregnancy: Teratogenic Effects. Pregnancy Category B: Reproduction studies have been performed in rats and mice at doses up to moderately maternally toxic dose concentrations (i.e., 200 mg/kg/day). These doses, based on a mg/m² basis, are estimated to be 4 and 2 times, respectively, the human daily dose of 500 mg. In the animal studies, no evidence of harm to the fetus due to azithromycin was found. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, azithromycin should be used during pregnancy only if clearly needed.
Nursing Mothers: It is not known whether azithromycin is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when azithromycin is administered to a nursing woman.

Gastrointestinal disturbances (nausea, vomiting, diarrhea, or abdominal pain) are the most frequent adverse effect but are usually mild and less frequent than with erythromycin.
Headache may occur and taste disturbances have been reported rarely. Other minor side effects: palpitations, chest pain, dyspepsia, flatulence, vomiting, melena, cholestatic jaundice, monilia, vaginitis, nephritis, dizziness, vertigo, somnolence, fatigue, rash, pruritus, photosensitivity and angioedema. Severe hypersensitivity reactions occur rarely but may be prolonged. Transient reductions in neutrophil counts have been seen in patients receiving azithromycin.

Azithromycin, unlike erythromycin and most macrolides, have little or no effect on hepatic cytochrome P450 isoenzymes, hence, may or may not exhibit adverse effects with astemizole, cisapride, and terfenadine.
Giving azithromycin with antacids containing aluminum or magnesium salts can reduce the rate, but not the extent, of its absorption; azithromycin should be given at least 1 hour before or 2 hours after the antacid.

Store at temperatures not exceeding 30°C. Protect from light.

Macrolides

J01FA10 - azithromycin ; Belongs to the class of macrolides. Used in the systemic treatment of infections.

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