Treatment of Influenza in Patients with Asthma
Oseltamivir 75 mg orally twice daily for 5 days is the first-line treatment for patients with asthma who contract influenza, and should be initiated as soon as possible, ideally within 48 hours of symptom onset. 1, 2, 3
Primary Antiviral Selection
Oseltamivir is the only appropriate antiviral for asthma patients because zanamivir is absolutely contraindicated in anyone with underlying airways disease, including asthma, due to risk of fatal bronchospasm. 4, 1, 3 The CDC explicitly states that zanamivir should not be administered to patients with chronic respiratory diseases such as asthma or COPD. 4
Standard Dosing
- Adults and adolescents ≥13 years: 75 mg orally twice daily for 5 days 2, 5
- Pediatric patients (weight-based):
- Renal impairment: Reduce to 75 mg once daily if creatinine clearance is 10-30 mL/min 1, 2
Critical Timing Considerations
Treatment should be initiated immediately without waiting for confirmatory testing when influenza is suspected during community influenza activity. 2 While maximum benefit occurs when started within 48 hours of symptom onset, patients with asthma are high-risk and may benefit even when treatment is initiated beyond 48 hours—do not withhold therapy based solely on timing. 1, 2, 3
The evidence strongly supports early treatment in asthma patients:
- Oseltamivir reduces illness duration by 24-36 hours (26% reduction) when started early 2
- In hospitalized patients, treatment provides mortality benefit (OR 0.21) even up to 96 hours after symptom onset 2
- Early antiviral therapy (within 48 hours) is associated with reduced severe outcomes in asthma patients (22% vs 44% severe outcomes when delayed) 6
Expected Clinical Benefits in Asthma Patients
Oseltamivir provides specific benefits for asthma patients beyond symptom reduction:
- Improved pulmonary function: 10.8% improvement in FEV1 versus 4.7% with placebo (p=0.0148) 7
- Reduced asthma exacerbations: 68% of treated patients avoided exacerbations versus 51% with placebo through day 7 (p=0.031) 7
- Reduced complications: 34% reduction in otitis media in pediatric patients 2
- Faster resolution of febrile illness in patients with chronic respiratory disease 5
However, the FDA label notes that a trial in adolescents and adults with chronic cardiac or respiratory disease was unable to demonstrate efficacy in time to alleviation of all symptoms, though more rapid cessation of fever was observed. 5
Medications to Avoid
Never prescribe adamantanes (amantadine or rimantadine) due to widespread resistance among circulating influenza A strains. 3 These agents are no longer recommended by the CDC. 3
Never prescribe zanamivir to any patient with asthma, COPD, or any history of reactive airways disease, regardless of current asthma control or severity. 4, 1, 3 This is an absolute contraindication due to risk of fatal bronchospasm. 1
Role of Antibiotics
Antibiotics are not routinely indicated for uncomplicated influenza with asthma exacerbation in the absence of bacterial pneumonia. 1 Consider antibiotics only if:
- Worsening symptoms develop after initial improvement 1
- Signs of bacterial pneumonia emerge (chest radiograph infiltrates, which are associated with severe outcomes—adjusted OR 9.38) 6
- Purulent sputum develops with systemic signs of infection 1
Common Pitfalls to Avoid
Do not withhold oseltamivir from high-risk asthma patients presenting slightly beyond 48 hours—they may still benefit significantly from treatment 1, 2, 3
Do not prescribe zanamivir to any patient with respiratory disease history, even if asthma is well-controlled or intermittent 4, 1, 3
Do not delay treatment while awaiting confirmatory testing in high-risk patients during influenza season 2
Do not discontinue oseltamivir early (before 5 days) to minimize resistance development 3
Do not use higher doses (150 mg twice daily)—no increased efficacy has been demonstrated in standard populations 5, 8
Additional Supportive Care
- Continue all regular asthma controller medications during influenza illness 4
- Fever-reducing medications are appropriate and were allowed in clinical trials 5
- Monitor peak flows and clinical asthma symptoms closely 4
- Approximately 10% of patients may experience nausea or vomiting with oseltamivir, which can be reduced by taking with food 2
Prevention Considerations
Annual inactivated influenza vaccination is recommended for all asthma patients to prevent influenza-related complications, though it should not be expected to reduce asthma exacerbation frequency during influenza season. 4 The live attenuated influenza vaccine (LAIV) is contraindicated in children aged 2-4 years with asthma or wheezing history, and should be used with caution in persons ≥5 years with asthma. 4