A-Rox

Approved Indications:

• Upper Respiratory Tract Infections (URTIs):
• Acute pharyngitis
• Tonsillitis
• Sinusitis
• Lower Respiratory Tract Infections (LRTIs):
• Acute bronchitis
• Exacerbation of chronic bronchitis
• Community-acquired pneumonia (mild to moderate)
• Skin and Soft Tissue Infections:
• Impetigo
• Folliculitis
• Cellulitis
• Genital Infections (Non-gonococcal):
• Nongonococcal urethritis
• Chlamydia trachomatis infections (e.g., cervicitis)
• Dental Infections:
• Odontogenic infections (e.g., periodontitis)

Clinically Accepted Off-Label Uses:

• Prophylaxis of bacterial endocarditis in penicillin-allergic patients
• Acne vulgaris (long-term use in low doses in combination with other agents)
• Helicobacter pylori eradication (as part of multi-drug regimens in select regions)

Route of Administration: Oral

Adults:

• Standard dose: 150 mg twice daily or 300 mg once daily
• Duration: 5–10 days depending on infection severity and type

Children (> 4 years and > 15 kg):

• 5–8 mg/kg/day, divided into two doses
• Max dose: 300 mg/day

Elderly:

• No specific dose adjustment required in patients with normal hepatic function
• Monitor for potential hepatic dysfunction

Renal Impairment:

• No dose adjustment required in mild to moderate impairment
• Use cautiously in severe impairment due to possible accumulation of metabolites

Hepatic Impairment:

• Use with caution; avoid in severe hepatic dysfunction

Administration Notes:

• Administer at least 15 minutes before meals for optimal absorption
• Do not chew or crush tablets

Roxithromycin is a semi-synthetic macrolide antibiotic that inhibits bacterial protein synthesis by binding reversibly to the 50S ribosomal subunit of susceptible microorganisms. This prevents the translocation steps in protein elongation, thereby suppressing the growth of bacteria. It exhibits primarily bacteriostatic activity but can be bactericidal at high concentrations or against highly susceptible organisms. Roxithromycin is effective against a broad range of Gram-positive cocci, atypical organisms (e.g., Mycoplasma, Chlamydia), and some Gram-negative bacteria.

• Absorption: Rapidly absorbed; peak plasma concentration reached within 1.5–2.5 hours. Bioavailability ~50%.
• Distribution: Widely distributed in tissues, especially lungs, tonsils, and prostate; low plasma protein binding (~96%).
• Metabolism: Partially metabolized in the liver via CYP3A4; major metabolite is inactive.
• Half-life: 10–14 hours, allowing once-daily dosing in some cases
• Elimination: Primarily excreted unchanged in feces (~50%) and minor amounts in urine (~10%)

Pregnancy:

• FDA Category B (prior classification): Animal studies have not demonstrated fetal risk; however, human data are limited. Use during pregnancy only if clearly needed.

Lactation:

• Excreted into human breast milk in small amounts
• Use with caution; monitor breastfed infants for gastrointestinal disturbances or candidiasis

• Primary Class: Macrolide Antibiotic
• Subclass: 14-membered ring macrolide
• Generation: Second-generation macrolide (semi-synthetic)

• Known hypersensitivity to roxithromycin, other macrolides, or any component of the formulation
• Severe hepatic impairment
• Concomitant use with drugs known to prolong QT interval
• History of QT prolongation or cardiac arrhythmias

• Cardiovascular Risk: Use with caution in patients with pre-existing cardiac conditions due to risk of QT prolongation and torsades de pointes
• Hepatic Impairment: Avoid in severe liver dysfunction; monitor liver enzymes if prolonged use
• Renal Impairment: Though primarily eliminated via feces, monitor patients with severe renal dysfunction
• Drug Resistance: Overuse may promote resistant bacterial strains
• Myasthenia Gravis: May worsen symptoms; monitor closely

Common Adverse Effects (≥1%):

• Gastrointestinal: Nausea, vomiting, abdominal pain, diarrhea, dyspepsia
• Nervous System: Headache, dizziness
• Skin: Rash, urticaria

Uncommon/Rare Side Effects:

• Hepatitis, cholestatic jaundice
• Taste disturbance
• Photosensitivity
• Elevation of liver enzymes (ALT, AST)

Serious Side Effects:

• QT prolongation, arrhythmias
• Anaphylaxis, angioedema
• Stevens-Johnson syndrome (extremely rare)

Timing & Severity:

• GI symptoms typically occur within the first few days of treatment and are dose-related
• Serious allergic reactions are rare but require immediate discontinuation

Major Drug Interactions:

• QT-Prolonging Agents (e.g., amiodarone, sotalol): Increased risk of arrhythmias
• CYP3A4 Substrates (e.g., theophylline, warfarin, carbamazepine): Roxithromycin may inhibit metabolism, increasing plasma concentrations
• Ergot alkaloids: Risk of ergotism; avoid concurrent use

Food Interaction:

• Absorption is decreased if taken with food; administer on an empty stomach

Alcohol Interaction:

• No direct interaction, but alcohol may exacerbate liver enzyme elevations

Enzyme System:

• CYP3A4 Inhibitor (mild to moderate)

• No major changes in indications or safety warnings by the FDA or EMA in recent years
• Clinical guidelines in some countries continue to include roxithromycin as an alternative macrolide in penicillin-allergic respiratory infection patients
• Ongoing global trend of macrolide resistance, especially in Streptococcus pneumoniae and Mycoplasma, suggests cautious use and local susceptibility testing

• Temperature: Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C
• Light/Humidity: Protect from moisture and direct sunlight
• Handling: Keep tablets in original blister packaging until use
• Oral Suspension (if available): Reconstituted suspension should be stored in the refrigerator (2°C–8°C) and used within 7–14 days depending on formulation. Shake well before each use.