Community data Updated 23 hours ago

Azithromycin Dihydrate

Macrolides Prescription

Indications

Pneumonia Bronchitis Sinusitis Pharyngitis Tonsillitis Bacterial Infection Respiratory Tract Infection Skin and Soft Tissue Infection Otitis Media

Azithromycin Dihydrate is used to treat infections caused by susceptible organisms. In the lower respiratory tract, that means bronchitis and pneumonia. In the upper respiratory tract, it covers sinusitis and pharyngitis/tonsillitis. It is also used for otitis media, and for skin and soft tissue infections. For sexually transmitted diseases in men and women, Azithromycin Dihydrate is indicated for non-gonococcal urethritis and cervicitis due to Chlamydia trachomatis.

⚠️ Always consult a registered physician before taking any medicine.

Pharmacology

Azithromycin is stable in acid, so it can be taken by mouth without any protection from stomach acid. It is absorbed readily, and absorption is greater on an empty stomach. In adults, the time to peak concentration is 2.1 to 3.2 hours for oral dosage forms. Phagocytes hold azithromycin in high concentration, so it is actively carried to the site of infection. During active phagocytosis, large amounts are released. The concentration in tissues can be over 50 times higher than in plasma, and this is due to ion trapping and high lipid solubility.

The half-life of azithromycin allows a large single dose to be given and still keep bacteriostatic levels in the infected tissue for several days. After a single 500 mg dose, plasma concentrations fell in a polyphasic pattern, with a mean apparent plasma clearance of 630 mL/min and a terminal elimination half life of 68 hours. This long terminal half-life is thought to be due to extensive uptake of the drug into tissues and its later release. Biliary excretion, mostly of unchanged drug, is a major route of elimination. Over a week, approximately 6% of the dose appears as unchanged drug in urine.

Microbiology

Azithromycin works by binding to the 50S ribosomal subunit of susceptible microorganisms, which interferes with microbial protein synthesis. Nucleic acid synthesis is not affected. It has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections.

Aerobic and facultative gram-positive microorganisms: Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus pyogenes.

Aerobic and facultative gram-negative microorganisms: Haemophilus ducreyi, Haemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae.

Other microorganisms: Chlamydia pneumoniae, Chlamydia trachomatis, Mycoplasma pneumoniae.

Betalactamase production should have no effect on azithromycin activity.

Aerobic and facultative gram-positive microorganisms: Streptococci (Groups C,F,G), Viridans group streptococci.

Aerobic and facultative gram-negative microorganisms: Bordetella pertussis, Legionella pneumophila.

Anaerobic microorganisms: Peptostreptococcus species, Prevotella bivia.

Pregnancy & Breastfeeding

Azithromycin Dihydrate falls under Pregnancy Category B. In animal reproduction studies, azithromycin showed no evidence of harm to the fetus. There are no adequate and well controlled studies in pregnant women, though. Animal studies don't always predict how humans will respond, so azithromycin should be used during pregnancy only if adequate alternatives are not available.

It is not known whether azithromycin is secreted in breast milk. For that reason, caution should be exercised when it is given to nursing women.

⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.

Dosage Reference

⚠️ Reference ranges from official sources only. Consult your doctor for personalized dosing.

Adults: For adults, the usual oral dose of azithromycin is 500 mg once daily for 3 days. Another schedule is 500 mg once on day 1, then 250 mg once daily on days 2 to 5 (4 days). For sexually transmitted diseases caused by Chlamydia trachomatis in adults, the dose is 1 gm given as a single dose. Alternatively, 500 mg once on day 1, followed by 250 mg once daily for the next 2 days, may also be given. Children over 6 months get 10 mg/kg body weight once daily for 3 days. By weight, that works out as 200 mg (1 teaspoonful) for 3 days if the child weighs 15 to 25 kg, 300 mg (1½ teaspoonfuls) for 3 days if the weight is 26 to 35 kg, and 400 mg (2 teaspoonfuls) for 3 days if the weight is 36 to 45 kg. In typhoid fever, 500 mg (2½ teaspoonfuls) is given once daily for 7 to 10 days. Azithromycin injection is for IV infusion only. For adults with community-acquired pneumonia due to the indicated organisms, the recommended dose is 500 mg as a single daily dose by the intravenous route for at least two days. After that, azithromycin is given by mouth as a single daily dose of 500 mg, taken as two 250-mg tablets, to complete a 7 to 10-day course. The doctor decides when to switch to the oral form, based on how the patient responds clinically. For adults with pelvic inflammatory disease due to the indicated organisms, the recommended dose is 500 mg as a single daily dose by the intravenous route for one or two days. Intravenous treatment is then followed by oral azithromycin at a single daily dose of 250 mg to complete a 7-day course. Again, the timing of the switch to oral treatment is left to the doctor and depends on clinical response. If anaerobic microorganisms are suspected of contributing to the infection, an antimicrobial agent with anaerobic activity should be given together with azithromycin. The safety and effectiveness of azithromycin injection in children or adolescents under 16 years have not been established.

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Azithromycin Dihydrate

Indications

Pharmacology

Pregnancy & Breastfeeding

Dosage Reference

Side Effects & Interactions

Side Effects

Key Interactions