Azithromycin: Price, Dosage & Where to Buy

Azithromycin is a macrolide antibiotic used to treat mild to moderate bacterial infections caused by susceptible organisms. It is also prescribed for the prevention and treatment of disseminated Mycobacterium avium complex disease in people with advanced HIV infection.

In the United Kingdom, azithromycin requires a prescription. Generic versions have been available since November 2005.

Azithromycin belongs to the macrolide class of antibiotics. Macrolides work by interfering with bacterial protein synthesis, which bacteria need to grow and multiply. The drug binds to the bacterial ribosome and stops the bacteria from making essential proteins.

Without these proteins, the bacteria cannot survive or reproduce. This action helps the body's immune system clear the infection. Azithromycin has a long half-life in body tissues, which means it stays active in the body for an extended period after dosing.

This property allows for less frequent dosing compared to some other antibiotics. The medicine is effective against a range of susceptible bacteria, including certain mycobacteria.

Azithromycin treats mild to moderate infections caused by susceptible bacteria. It is indicated for mycobacterial infections, specifically for the prevention of disseminated Mycobacterium avium complex disease in people with advanced HIV infection. When used alone or combined with rifabutin, azithromycin helps prevent MAC disease.

For treatment of disseminated MAC infections in people with advanced HIV infection, azithromycin is used in combination with ethambutol. The medicine should only be used to treat infections that are proven or strongly suspected to be caused by susceptible bacteria, helping to reduce the development of drug-resistant organisms and maintain the effectiveness of antibacterial drugs.

The label lists tablets in 250 mg, 500 mg, and 600 mg strengths. Oral suspension is available as powder that reconstitutes to 100 mg/5 mL and 200 mg/5 mL. Injectable forms and ophthalmic drops are also listed.

For prevention of disseminated MAC disease, the label lists 1,200 mg taken once weekly. This dose may be combined with rifabutin.

For treatment of disseminated MAC infections, azithromycin should be taken at a daily dose of 600 mg in combination with ethambutol at 15 mg/kg daily. Azithromycin can be taken with or without food, though increased tolerability has been observed when tablets are taken with food.

The label lists storage at 20° to 25°C, with excursions permitted from 15° to 30°C. Azithromycin tablets should be dispensed in tight containers to maintain quality. Keep the medicine in its original packaging until use, protected from excessive heat and moisture.

Store out of reach of children. Do not use azithromycin after the expiry date printed on the packaging. Follow any additional storage instructions on the label or as directed by a pharmacist.

If a dose is missed, the general approach depends on the dosing schedule. For once-weekly dosing such as the 1,200 mg regimen for MAC prevention, contact a pharmacist or doctor for guidance on when to take the missed dose. For daily dosing regimens such as the 600 mg daily treatment dose, take the missed dose as soon as remembered unless it is nearly time for the next scheduled dose.

Do not double doses to make up for a missed one. Maintaining a consistent schedule helps ensure the medicine works effectively against the infection.

Available data from published literature and postmarketing experience over several decades with azithromycin use in pregnant women have not identified any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes. Developmental toxicity studies in rats, mice, and rabbits showed no drug-induced fetal malformations at doses up to 3, 2, and 1 times, respectively, an adult human daily dose of 600 mg based on body surface area. Azithromycin is present in human milk.

Non-serious adverse reactions have been reported in breastfed infants after maternal administration of azithromycin. Women who are breastfeeding should monitor the infant for diarrhoea, vomiting, or rash.