How to Prescribe Tamiflu and Augmentin Together
For influenza pneumonia, immediately initiate oseltamivir (Tamiflu) 75 mg orally twice daily for 5 days plus co-amoxiclav (Augmentin) as first-line antibiotic therapy, with the specific antibiotic regimen stratified by pneumonia severity. 1, 2
Antiviral Therapy: Oseltamivir (Tamiflu)
Dosing and Duration:
- Standard dose: 75 mg orally every 12 hours for 5 days 3, 1
- Renal adjustment: Reduce to 75 mg once daily if creatinine clearance <30 mL/min 1, 3
- Administration: May be taken with or without food, though tolerability is enhanced when taken with food 3, 4
Timing Considerations:
- Ideally initiate within 48 hours of symptom onset 3, 5
- However, hospitalized patients with pneumonia benefit from oseltamivir even when started >48 hours after symptom onset, particularly if immunocompromised 1, 2
- Earlier initiation within 24 hours of admission significantly reduces 30-day mortality, especially in patients with respiratory failure 6
Antibiotic Therapy: Co-amoxiclav (Augmentin)
The antibiotic regimen depends entirely on pneumonia severity:
Non-Severe Influenza-Related Pneumonia (CURB-65 Score 0-2):
- First-line oral therapy: Co-amoxiclav (amoxicillin-clavulanate) 7, 1, 2
- Alternative: Doxycycline if co-amoxiclav is contraindicated 7, 1
- Duration: 7 days for uncomplicated pneumonia 7, 1
Severe Influenza-Related Pneumonia (CURB-65 Score ≥3 or bilateral infiltrates):
- Immediate IV combination therapy required: Co-amoxiclav OR 2nd/3rd generation cephalosporin (cefuroxime or cefotaxime) PLUS a macrolide (clarithromycin or erythromycin) 7, 1, 2
- Critical timing: Antibiotics must be administered within 4 hours of admission 7, 1
- Duration: 10 days for severe, microbiologically undefined pneumonia 7, 1
Route Switching Strategy:
- Switch from IV to oral antibiotics when: Clinical improvement occurs AND temperature has been normal for 24 hours AND no contraindication to oral route exists 7, 2
Clinical Algorithm for Combined Therapy
Step 1: Confirm influenza pneumonia diagnosis
- Use RT-PCR or nucleic acid amplification test for confirmation 8
Step 2: Assess pneumonia severity using CURB-65 score
- Score ≥3 indicates severe pneumonia requiring hospitalization and IV therapy 9
Step 3: Initiate dual therapy immediately
- Start oseltamivir 75 mg PO BID regardless of timing from symptom onset if hospitalized 1, 2
- Start antibiotics within 4 hours: oral co-amoxiclav for non-severe OR IV combination therapy for severe 7, 1
Step 4: Monitor for treatment failure
- For non-severe pneumonia not responding to co-amoxiclav: switch to fluoroquinolone with pneumococcal and staphylococcal coverage 7
- For severe pneumonia not responding to combination therapy: add antibiotics effective against MRSA 7
Critical Pitfalls to Avoid
Common errors in prescribing this combination:
- Do NOT withhold oseltamivir if >48 hours from symptom onset in hospitalized patients with pneumonia – they still benefit, especially if immunocompromised 1, 2
- Do NOT use azithromycin monotherapy – it is inadequate for influenza-related pneumonia; co-amoxiclav is required as first-line 2
- Do NOT delay antibiotics beyond 4 hours of admission – this critical window significantly impacts mortality 7, 1
- Do NOT forget renal dose adjustment – oseltamivir requires reduction to 75 mg once daily if CrCl <30 mL/min 1, 3
Special Populations
High-risk patients requiring antibiotics even without confirmed pneumonia:
- Patients with chronic comorbidities presenting with lower respiratory tract features should receive antibiotics in addition to oseltamivir 7
- Previously well adults with worsening symptoms (recrudescent fever or increasing dyspnea) after initial improvement require antibiotic addition 7, 2
Immunocompromised patients:
- Benefit significantly from oseltamivir even with delayed initiation 1, 2
- May require extended prophylaxis up to 12 weeks in certain circumstances 3