Zithromax (azithromycin) is a macrolide antibiotic medication prescribed to treat a wide variety of bacterial infections. Its advanced azalide subclass structure allows for a unique pharmacokinetic profile, facilitating a shorter treatment duration and improved patient compliance compared to many older antibiotics. Clinicians value its broad-spectrum activity against common pathogens responsible for respiratory, skin, and sexually transmitted infections. This medication represents a cornerstone in modern antimicrobial therapy due to its efficacy and well-established safety profile.

Features

• Active ingredient: Azithromycin
• Drug class: Macrolide (azalide subclass) antibiotic
• Available forms: Oral tablets, oral suspension, and intravenous solution
• Standard dosing: Often a single daily dose
• Treatment course: Frequently shorter (3-5 days) for many indications
• Spectrum: Broad activity against Gram-positive, Gram-negative, and atypical bacteria

Benefits

• Effective against common community-acquired pathogens including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis
• Convenient once-daily dosing regimen improves adherence to therapy
• Short course treatment duration reduces overall antibiotic exposure
• Generally well-tolerated with a favorable safety profile in appropriate patients
• Available in multiple formulations suitable for different age groups and clinical situations
• Demonstrated efficacy in treating respiratory infections, skin/soft tissue infections, and certain sexually transmitted diseases

Common use

Zithromax is commonly prescribed for bacterial pharyngitis, acute bacterial exacerbations of chronic obstructive pulmonary disease, community-acquired pneumonia, uncomplicated skin and skin structure infections, and urethritis/cervicitis caused by Chlamydia trachomatis. It is also used in the treatment of otitis media in children and for the prevention and treatment of Mycobacterium avium complex (MAC) in immunocompromised patients. Off-label uses include the treatment of certain gastrointestinal infections and as part of combination therapy for Helicobacter pylori eradication.

Dosage and direction

Dosage varies significantly based on the infection being treated, patient age, renal function, and formulation. For most respiratory and skin infections in adults: 500 mg as a single dose on the first day, followed by 250 mg once daily for four days. For sexually transmitted infections: single 1 gram dose. Pediatric dosing is weight-based. The oral suspension should be shaken well before administration. Tablets may be taken with or without food, though administration with food may reduce gastrointestinal upset. Complete the full prescribed course even if symptoms improve earlier.

Precautions

Patients should disclose complete medical history, particularly regarding liver disease, kidney disease, myasthenia gravis, or cardiac conditions including arrhythmias. Use with caution in patients with known QT prolongation or those taking medications that prolong the QT interval. May cause exacerbation of symptoms in patients with myasthenia gravis. Monitor for signs of superinfection or Clostridium difficile-associated diarrhea. Not appropriate for viral infections. Use during pregnancy only if clearly needed; azithromycin does enter breast milk.

Contraindications

Known hypersensitivity to azithromycin, erythromycin, or any macrolide antibiotic. Contraindicated in patients with history of cholestatic jaundice/hepatic dysfunction associated with prior azithromycin use. Should not be used concomitantly with ergot derivatives or drugs that significantly prolong QT interval such as pimozide. Not recommended in patients with known hypokalemia or hypomagnesemia. Severe hepatic impairment requires careful consideration before administration.

Possible side effect

Common side effects include diarrhea/loose stools (5-10%), nausea (3-5%), abdominal pain (2-3%), and vomiting. Less frequently reported: headache, dizziness, rash, and vaginitis. Serious but rare side effects include QT prolongation, torsades de pointes, hepatotoxicity, Clostridium difficile-associated diarrhea, and allergic reactions. Hearing loss, particularly in elderly patients or those receiving high doses, has been reported. Cases of rhabdomyolysis have been documented, though causality remains uncertain.

Drug interaction

Significant interactions occur with antacids containing aluminum or magnesium (reduce azithromycin absorption; separate administration by 2 hours). Increases concentration of warfarin (monitor INR), digoxin, phenytoin, and cyclosporine. Concomitant use with nelfinavir increases azithromycin levels. QT prolonging agents (antiarrhythmics, antipsychotics, fluoroquinolones) may have additive effects. May potentiate effects of ergot derivatives. Colchicine toxicity may be enhanced in patients with renal impairment.

Missed dose

Take the missed dose as soon as remembered, unless it is almost time for the next scheduled dose. Do not double the dose to make up for a missed one. If multiple doses are missed, contact your healthcare provider for guidance. Maintaining consistent antibiotic levels is important for efficacy, but single missed doses are generally not critical with azithromycin’s prolonged half-life.

Overdose

Symptoms may include severe nausea, vomiting, diarrhea, and temporary hearing loss. Management is supportive; gastric lavage may be considered if presentation is immediate. There is no specific antidote. Hemodialysis does not significantly remove azithromycin. Monitor ECG for QT prolongation if large overdose is suspected. Contact poison control center or emergency department immediately for guidance.

Storage

Store at room temperature (15-30°C or 59-86°F) in original container. Keep away from moisture and light. Oral suspension remains stable for 10 days after reconstitution when refrigerated; discard any unused portion after this period. Do not freeze. Keep all medications out of reach of children and pets. Do not transfer to other containers unless specifically instructed.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before starting, changing, or stopping any medication. Dosage and treatment decisions should be made based on individual patient factors and professional medical judgment. The prescriber should reference complete prescribing information before administration.

Reviews

Clinical studies demonstrate azithromycin’s efficacy with cure rates exceeding 85-95% for approved indications. Meta-analyses confirm its non-inferiority to comparator antibiotics for respiratory infections. The short-course regimen is consistently rated higher for patient satisfaction and adherence compared to longer antibiotic courses. Some concerns have emerged regarding cardiovascular risk in specific populations, though the absolute risk remains low for most patients. Emerging bacterial resistance patterns require ongoing surveillance and appropriate use.