What is the recommended treatment for a 13-14 year old patient who is influenza (flu) positive?

Treatment for Influenza-Positive 13-14 Year Old

For a 13-14 year old with confirmed influenza, treat with oseltamivir 75 mg orally twice daily for 5 days, ideally initiated within 48 hours of symptom onset. 1

Weight-Based Dosing for Adolescents

For adolescents 13 years and older, the dosing is standardized regardless of weight:

• 75 mg orally twice daily for 5 days 1, 2
• This applies to all patients in this age group weighing >40 kg (>88 lb) 1

If the patient weighs ≤40 kg (uncommon for this age), use pediatric weight-based dosing:

• 23.1-40 kg: 60 mg twice daily 1
• 15.1-23 kg: 45 mg twice daily 1

Timing of Treatment Initiation

Treatment should be started within 48 hours of symptom onset for optimal benefit 1, 2:

• Initiating within 12 hours reduces illness duration by 3.1 days (41%) compared to treatment at 48 hours 3
• Treatment within 24 hours provides the greatest benefit, reducing illness duration by approximately 1.5 days 4, 3
• Even if presenting after 48 hours, treatment should still be considered for patients with moderate-to-severe or progressive disease 1

Administration Details

• Oseltamivir can be taken with or without food, though administration with meals improves gastrointestinal tolerability 1, 2
• Available as 75 mg capsules or oral suspension (6 mg/mL concentration = 12.5 mL per 75 mg dose) 1, 2
• Complete the full 5-day course regardless of symptom improvement 1

Alternative Antiviral Options

If oseltamivir is not available or contraindicated, consider:

Zanamivir (inhaled):

• 10 mg (two 5-mg inhalations) twice daily for 5 days 1
• Approved for patients ≥7 years 1
• Avoid in patients with underlying airway disease (asthma, COPD) 1

Peramivir (intravenous):

• Single 600 mg IV infusion over 15-30 minutes 1
• Approved for ages 13-17 years 1
• Reserved for patients unable to take oral/inhaled medications 1

Baloxavir:

• Single oral dose based on weight: 40 mg for 40-80 kg, 80 mg for >80 kg 1
• Approved for patients ≥12 years 1
• Newer agent with less long-term safety data 1

Clinical Benefits of Treatment

Oseltamivir treatment in adolescents provides:

• Reduction in illness duration by 19-30% 1, 5
• Faster resolution of fever (57% fewer patients remain febrile at 48 hours) 5
• Decreased severity of troublesome symptoms (fatigue reduced by 29%, myalgia by 26%) 5
• Reduced risk of secondary complications requiring antibiotics 4
• Faster return to normal activities and health status 5

Special Considerations

High-risk patients (chronic cardiac/respiratory disease, immunocompromised) should receive treatment regardless of timing, as benefits may extend beyond 48 hours 1:

• These patients show significant reduction in acute febrile illness duration even with delayed treatment 5

Renal impairment:

• For creatinine clearance 10-30 mL/min: reduce to 75 mg once daily for 5 days 1

Common Pitfalls to Avoid

• Do not withhold treatment if presenting after 48 hours in moderate-to-severe cases - some benefit persists with later initiation 1
• Do not routinely prescribe antibiotics unless bacterial co-infection is documented or highly suspected 1, 6
• Do not use amantadine or rimantadine - widespread resistance makes these ineffective against current influenza strains 1
• Do not rely solely on rapid antigen tests for diagnosis in hospitalized patients - molecular assays (RT-PCR, NAAT) are preferred for accuracy 7, 6

Tolerability

Oseltamivir is well tolerated in adolescents 1:

• Most common adverse effects: nausea and vomiting (transient, typically only with first dose) 4, 3
• Discontinuation rate is low (1.8%) 3
• Taking with food significantly reduces gastrointestinal symptoms 3, 5