Xtoro - Drug Monograph

Introduction

Xtororo (finafloxacin otic suspension) is a fluoroquinolone antimicrobial agent specifically formulated for otic use. It is indicated for the treatment of acute otitis externa (AOE) caused by susceptible microorganisms. Xtoro represents a specialized formulation that demonstrates enhanced activity in acidic environments, which is particularly relevant for infected ear canals where pH is often lowered.

Mechanism of Action

Finafloxacin, the active component of Xtoro, is a broad-spectrum fluoroquinolone antibacterial that inhibits bacterial DNA gyrase and topoisomerase IV. Unlike other fluoroquinolones, finafloxacin demonstrates increased antibacterial activity in acidic environments (pH 5.0-6.0), which commonly occur in infected ears. This unique property allows for enhanced efficacy against pathogens commonly associated with otitis externa.

Indications

Xtoro is indicated for the treatment of acute otitis externa (AOE) caused by susceptible isolates of Pseudomonas aeruginosa and Staphylococcus aureus.

Dosage and Administration

• Recommended dosage: 4 drops instilled into the affected ear twice daily for 7 days
• Administration: Patient should lie with affected ear upward before instillation. Drops should be administered, and patient should remain in position for 1 minute to facilitate penetration
• Special populations: Safety and effectiveness in pediatric patients below 6 months of age have not been established. No dosage adjustment required for geriatric patients or those with renal/hepatic impairment
• Storage: Store at room temperature (20-25°C/68-77°F)

Pharmacokinetics

• Absorption: Minimal systemic absorption following otic administration. Plasma concentrations are generally below quantifiable limits (<1 ng/mL)
• Distribution: Primarily local action with minimal systemic distribution
• Metabolism: Not extensively studied due to minimal systemic exposure
• Elimination: Primarily through local mechanisms with negligible renal excretion

Contraindications

• Hypersensitivity to finafloxacin, other quinolones, or any component of the formulation
• History of hypersensitivity reactions to other fluoroquinolones

Warnings and Precautions

• Superinfections: As with other antibacterial agents, prolonged use may result in overgrowth of nonsusceptible organisms including fungi
• Systemic effects: Although systemic absorption is minimal, potential for systemic quinolone effects should be considered
• Perforated tympanic membrane: Safety and effectiveness in patients with perforated tympanic membrane have not been established
• Contact lens wear: Patients should avoid wearing contact lenses if they have otitis externa involving the eye area

Drug Interactions

• Minimal systemic absorption suggests low potential for clinically significant drug interactions
• No formal drug interaction studies have been conducted due to minimal systemic exposure
• Theoretical interactions with systemically administered quinolones should be considered if used concomitantly

Adverse Effects

• Pruritus (itching)
• Ear discomfort
• Ear congestion
• Application site pain

• Dermatitis
• Erythema
• Ear edema
• Hypersensitivity reactions

Monitoring Parameters

• Clinical signs and symptoms of acute otitis externa
• Resolution of infection after completion of therapy
• Signs of superinfection or fungal overgrowth
• Local tolerance and signs of hypersensitivity reactions

Patient Education

• Complete the full course of therapy even if symptoms improve
• Administer exactly as prescribed (twice daily for 7 days)
• Proper instillation technique: Lie with affected ear upward, instill drops, remain in position for 1 minute
• Avoid contaminating the dropper tip
• Do not use in eyes or swallow the medication
• Report any signs of allergic reaction (rash, itching, swelling) or worsening symptoms
• Store at room temperature and discard unused portion after therapy completion

References

1. FDA prescribing information: Xtoro (finafloxacin otic suspension) 2. Dryden MS, et al. A comparison of the efficacy and safety of finafloxacin otic solution vs. otiprio in the treatment of acute otitis externa. J Antibiot. 2018;71(6):577-585 3. Jones RN, et al. Antimicrobial activity of finafloxacin against contemporary pathogens isolated from acute otitis externa. Diagn Microbiol Infect Dis. 2018;90(3):196-200 4. ClinicalTrials.gov: Efficacy and Safety Study of Finafloxacin Otic Suspension for Treatment of Acute Otitis Externa 5. European Medicines Agency Assessment Report: Finafloxacin otic suspension