What is the recommended treatment for Pertussis (Whooping Cough)?

Treatment of Pertussis (Whooping Cough)

Azithromycin is the preferred first-line treatment for pertussis in all age groups due to its better tolerability, fewer side effects, and more convenient dosing schedule compared to alternatives. 1

Recommended Antimicrobial Regimens

Azithromycin (First-line)

• Infants <6 months: 10 mg/kg per day for 5 days 2, 1
• Infants and children ≥6 months: 10 mg/kg (maximum: 500 mg) on day 1, followed by 5 mg/kg per day (maximum: 250 mg) on days 2-5 2, 1
• Adults: 500 mg on day 1, followed by 250 mg per day on days 2-5 2, 1

Erythromycin (Alternative)

• Infants <1 month: Not preferred due to risk of infantile hypertrophic pyloric stenosis (IHPS). Use azithromycin instead. If unavailable, dose is 40-50 mg/kg per day in 4 divided doses for 14 days with monitoring for IHPS 2
• Infants ≥1 month and children: 40-50 mg/kg per day (maximum: 2 g per day) in 4 divided doses for 14 days 2, 3
• Adults: 2 g per day in 4 divided doses for 14 days 2, 3

Clinical Evidence and Considerations

Azithromycin has demonstrated equal efficacy to erythromycin with significantly fewer side effects. In a large randomized controlled trial, bacterial eradication rates were 100% for both azithromycin and erythromycin, but gastrointestinal adverse events were reported less frequently with azithromycin (18.8%) compared to erythromycin (41.2%) 4. Additionally, compliance was markedly better with azithromycin (90% took all prescribed doses) compared to erythromycin (only 55% took all prescribed doses) 4.

Special Considerations

Neonates and Young Infants

• Azithromycin is strongly preferred for infants <1 month due to the risk of IHPS with erythromycin 2, 1
• The high case-fatality ratio of pertussis in neonates underscores the importance of prompt treatment 2

Timing of Treatment

• Antibiotics are most effective when started during the early catarrhal stage of illness 5
• While antibiotics may not affect the course of established paroxysmal cough, they remain important for reducing transmission 5, 4

Drug Interactions and Contraindications

• Azithromycin should be prescribed with caution to patients with impaired hepatic function 2, 1
• Avoid concurrent administration of azithromycin with aluminum- or magnesium-containing antacids 2, 1
• Monitor patients when azithromycin is used with drugs metabolized by cytochrome P450 or those with pharmacokinetic interactions (e.g., digoxin, triazolam, ergot alkaloids) 1
• Macrolides are contraindicated in patients with history of hypersensitivity to any macrolide agent 2

Additional Management Considerations

• Patients should be isolated at home and away from work or school for 5 days after starting antibiotic therapy 1
• Supportive care is important, especially for infants and young children who are at higher risk for complications such as apnea, pneumonia, seizures, or death 5
• Antibiotics should not be used prophylactically at late periods of pertussis for prevention of secondary bacterial complications, as this may increase risk of complications 6

Common Pitfalls to Avoid

1. Delaying treatment: Early treatment is crucial for reducing transmission and may help reduce symptom severity if initiated during the catarrhal phase 5

2. Using erythromycin in neonates: Avoid erythromycin in infants <1 month due to risk of IHPS; use azithromycin instead 2, 1

3. Poor monitoring of compliance: The 14-day course of erythromycin leads to poor compliance; the shorter 5-day course of azithromycin improves adherence 4

4. Failure to identify and treat close contacts: Postexposure prophylaxis should be considered for household contacts and those at high risk 1

5. Overlooking supportive care: While antibiotics address the infection, supportive care is essential, particularly for managing cough paroxysms and preventing complications in young children 5