Roxithromycin is a semi-synthetic macrolide antibiotic derived from erythromycin, designed to offer enhanced pharmacokinetic properties and a broad spectrum of antibacterial activity. It is particularly valued for its improved acid stability, extended half-life, and high tissue penetration, making it a reliable choice for treating a variety of community-acquired infections. Clinicians frequently prescribe roxithromycin for respiratory, skin, and soft tissue infections due to its efficacy against common pathogens and favorable tolerability profile. Its once- or twice-daily dosing regimen supports patient adherence, contributing to successful therapeutic outcomes.

Features

• Chemical structure: 14-membered lactone ring with oxime modification
• Molecular formula: C₄₁H₇₆N₂O₁₅
• Molecular weight: 837.06 g/mol
• Administration: Oral tablet form
• Standard strengths: 150 mg and 300 mg tablets
• Bioavailability: Approximately 50–60% following oral administration
• Protein binding: 85–95%, primarily to alpha-1-acid glycoprotein
• Elimination half-life: 8–15 hours in adults with normal renal function
• Excretion: Primarily hepatic, with metabolites eliminated via bile and feces

Benefits

• Demonstrates potent bacteriostatic activity against Gram-positive cocci, including Streptococcus pneumoniae and Staphylococcus aureus
• Effective against atypical pathogens such as Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila
• Convenient once- or twice-daily dosing supports compliance and reduces missed doses
• Generally well-tolerated with a lower incidence of gastrointestinal side effects compared to older macrolides
• Suitable for use in both adult and pediatric populations (where approved and appropriately dosed)
• Provides reliable tissue penetration, achieving concentrations effective at sites of infection

Common use

Roxithromycin is indicated for the treatment of mild to moderate bacterial infections caused by susceptible organisms. Common clinical applications include:

• Upper and lower respiratory tract infections, such as pharyngitis, tonsillitis, acute bronchitis, and community-acquired pneumonia
• Skin and soft tissue infections, including impetigo, erysipelas, and secondary infected dermatoses
• Genitourinary infections caused by Chlamydia trachomatis
• Dental infections, such as periodontitis and pericoronitis, where anaerobic and Gram-positive coverage is required
• Prophylaxis against bacterial endocarditis in high-risk patients undergoing dental or surgical procedures (in specific regions and under guidelines)

Dosage and direction

The standard adult dosage for roxithromycin is 300 mg per day, administered either as a single dose or in two divided doses of 150 mg each. For severe infections, the dose may be increased to 300 mg twice daily, though this should be guided by clinical judgment and microbial susceptibility.

For pediatric patients (where approved and available in suitable formulations), dosing is typically based on body weight, often 2.5–5 mg/kg twice daily, not to exceed adult doses.

Administration should occur with or without food, though taking it with food may minimize potential gastrointestinal discomfort. Tablets should be swallowed whole with a full glass of water; crushing or chewing is not recommended.

The usual treatment duration ranges from 5 to 10 days, depending on the type and severity of infection. Completion of the full prescribed course is essential to prevent recurrence and resistance development.

Precautions

• Use with caution in patients with hepatic impairment, as roxithromycin is metabolized in the liver; consider dose adjustment or monitoring of liver function tests.
• Exercise care in patients with renal impairment, although dosage modification is generally not required unless severe impairment exists.
• May prolong the QT interval; avoid use in patients with known QT prolongation, electrolyte disturbances, or concurrent use of other QT-prolonging drugs.
• Not recommended during pregnancy unless clearly needed and benefits outweigh risks; limited human data available.
• Use during lactation should be cautious, as macrolides are excreted in breast milk.
• Superinfection with resistant bacteria or fungi may occur; monitor for new symptoms.
• Inform patients that roxithromycin may cause dizziness or visual disturbances; advise against driving or operating machinery if affected.

Contraindications

• Hypersensitivity to roxithromycin, other macrolide antibiotics, or any component of the formulation.
• History of hepatitis or jaundice associated with prior macrolide use.
• Concurrent administration with ergot derivatives, cisapride, terfenadine, or astemizole due to risk of serious cardiac events.
• Patients with known severe QT prolongation or ventricular arrhythmias.
• Combination with colchicine in patients with renal or hepatic impairment.

Possible side effect

Most side effects are mild to moderate and often resolve with continued use or upon discontinuation. Commonly reported adverse reactions include:

• Gastrointestinal: Nausea, vomiting, abdominal pain, diarrhea, dyspepsia
• Dermatological: Rash, pruritus, urticaria
• Hepatic: Transient elevations in liver enzymes, hepatitis (rare)
• Neurological: Dizziness, headache, taste perversion
• Cardiac: QT prolongation (rare, usually in predisposed patients)
• Other: Oral or vaginal candidiasis due to alteration of normal flora

Serious side effects are uncommon but may include hepatotoxicity, Clostridioides difficile-associated diarrhea, anaphylaxis, or severe skin reactions. Patients should seek medical attention if severe or persistent symptoms occur.

Drug interaction

Roxithromycin is a substrate and inhibitor of CYP3A4 and may interact with numerous medications. Key interactions include:

• Increased levels of: Theophylline, carbamazepine, cyclosporine, digoxin, warfarin (monitor levels and adjust doses as needed)
• Contraindicated with: Ergot alkaloids, cisapride, terfenadine, astemizole (risk of QT prolongation and torsades de pointes)
• Potential interaction with: Statins (increased risk of myopathy), midazolam, triazolam (enhanced sedation)
• Reduced efficacy of: Oral contraceptives (advise backup contraception during and shortly after therapy)
• Interaction with antacids or H2 blockers: May reduce roxithromycin absorption; administer at least 2 hours apart

Missed dose

If a dose is missed, it should be taken as soon as remembered, unless it is nearly time for the next scheduled dose. In that case, skip the missed dose and resume the regular dosing schedule. Do not double the dose to make up for a missed one. Maintaining consistent dosing intervals helps ensure optimal antibiotic levels and efficacy.

Overdose

Symptoms of overdose may include severe nausea, vomiting, diarrhea, and abdominal cramping. QT prolongation and hearing loss have been reported in extreme cases. Management is supportive and symptomatic; there is no specific antidote. Gastric lavage or activated charcoal may be considered if ingestion was recent. Monitor cardiac function and electrolyte levels in cases of significant overdose.

Storage

Store roxithromycin tablets at room temperature (15–30°C or 59–86°F), in a dry place, protected from light and moisture. Keep the container tightly closed and out of reach of children and pets. Do not use beyond the expiration date printed on the packaging.

Disclaimer

This information is intended for healthcare professionals and educated patients as a summary of roxithromycin’s characteristics and is not exhaustive. Always consult a qualified healthcare provider for personalized medical advice, diagnosis, or treatment. Do not initiate, adjust, or discontinue therapy without professional guidance. Local prescribing information and guidelines may vary.

Reviews

Roxithromycin is generally well-regarded in clinical practice for its balance of efficacy, tolerability, and convenience. Healthcare providers appreciate its reliable activity against respiratory pathogens and its role in managing community-acquired infections. Patients often report satisfaction with the once-daily dosing and lower incidence of gastrointestinal upset compared to some other antibiotics. However, as with all antimicrobials, prudent use is encouraged to mitigate resistance development.