What treatment is recommended for a patient with asthma who has contracted influenza (flu) and should they continue their asthma medications while taking Tamiflu (oseltamivir)?

Treatment of Influenza in Patients with Asthma

Patients with asthma who contract influenza should receive oseltamivir (Tamiflu) treatment immediately, ideally within 48 hours of symptom onset, and should continue all their regular asthma maintenance medications without interruption. 1

Oseltamivir Treatment for Asthmatic Patients

Oseltamivir provides significant clinical benefits in asthmatic children with influenza, particularly improving lung function and reducing asthma exacerbations, even though symptom duration reduction may be less pronounced than in otherwise healthy children. 1, 2

Evidence-Based Benefits in Asthma Patients

• A randomized controlled trial specifically in influenza-infected children with asthma demonstrated significantly greater improvement in forced expiratory volume (FEV1) among oseltamivir-treated patients (10.8% versus 4.7%; P = 0.0148) compared to placebo. 2

• The same study showed oseltamivir-treated asthmatic children experienced fewer asthma exacerbations up to day 7 (68% versus 51%; P = 0.031). 2

• While oseltamivir reduced illness duration by only 10.4 hours (8%; P = 0.542) in asthmatic children—a nonsignificant reduction—the pulmonary function benefits and reduced exacerbation rates make treatment clearly beneficial. 1, 2

• Meta-analyses confirm no significant effect of oseltamivir on reducing illness duration specifically in asthmatic children, but the drug's impact on preventing complications and improving lung function justifies its use. 1

Dosing Recommendations

• Adults and adolescents ≥13 years: 75 mg orally twice daily for 5 days. 1, 3

• Pediatric weight-based dosing (twice daily for 5 days):

  • ≤15 kg: 30 mg twice daily

  • 15-23 kg: 45 mg twice daily

  • 23-40 kg: 60 mg twice daily

  • 40 kg: 75 mg twice daily 1

• Dose adjustment required for renal impairment (creatinine clearance <30 mL/min): reduce to 75 mg once daily. 3, 4

Continuation of Asthma Medications

All baseline asthma controller medications (inhaled corticosteroids, long-acting beta-agonists, leukotriene modifiers) must be continued during influenza treatment. 3

• Influenza infection itself triggers airway inflammation and can precipitate asthma exacerbations, making maintenance therapy even more critical during acute viral illness. 2

• Rescue bronchodilator use (short-acting beta-agonists) should be available and may need to be increased during the acute illness. 2

• There are no drug interactions between oseltamivir and standard asthma medications that would necessitate dose adjustments or discontinuation. 5

Treatment Timing Considerations

• Optimal benefit occurs when oseltamivir is initiated within 48 hours of symptom onset, but treatment should not be withheld in high-risk patients (including those with asthma) presenting beyond 48 hours. 1

• Patients with chronic respiratory diseases like asthma are considered high-risk and may benefit from treatment even when started after 48 hours, particularly if they have moderate-to-severe or progressive disease. 1, 3

• Do not wait for laboratory confirmation of influenza before initiating treatment in asthmatic patients during influenza season—empiric treatment based on clinical presentation is appropriate. 3, 4

Expected Clinical Outcomes

• Reduction in asthma exacerbations during the acute influenza illness. 1, 2

• Improved pulmonary function (FEV1) compared to untreated patients. 2

• Decreased risk of secondary bacterial complications, including pneumonia (50% risk reduction) and sinusitis. 1, 3

• Potential reduction in need for antibiotics (37% versus 69% in high-risk patients). 6

Safety and Tolerability

• Oseltamivir is safe and well-tolerated in asthmatic children and adults. 2, 6

• The most common adverse effect is nausea and vomiting (occurring in approximately 5-15% of patients), which is mild, transient, and less likely when taken with food. 1, 5

• No established link exists between oseltamivir and neuropsychiatric events, though neurologic complications can occur with influenza itself. 1

• Zanamivir (inhaled neuraminidase inhibitor) is not recommended for patients with asthma or chronic obstructive pulmonary disease due to increased risk of bronchospasm. 1

Critical Clinical Pitfalls to Avoid

• Never withhold oseltamivir from asthmatic patients while waiting for influenza test results—rapid antigen tests have poor sensitivity, and negative results should not exclude treatment in high-risk patients. 3, 4

• Do not discontinue asthma controller medications during influenza treatment, as this increases risk of exacerbations. 2

• Do not assume lack of fever excludes influenza in asthmatic patients, particularly if immunocompromised or elderly—these patients may not mount adequate febrile responses. 3, 4

• Monitor closely for secondary bacterial pneumonia if symptoms worsen or fail to improve after 3-5 days of oseltamivir treatment—this may require addition of antibiotics. 4, 6