What is the first-line treatment for whooping cough (pertussis)?

First-Line Treatment for Whooping Cough (Pertussis)

Azithromycin is the first-line treatment for pertussis (whooping cough) due to its effectiveness, better tolerability, and convenient dosing schedule compared to other macrolides. 1

Treatment Recommendations by Age Group

Infants < 1 month

• Azithromycin is the preferred macrolide for treatment and postexposure prophylaxis 1
• Erythromycin is not recommended due to risk of infantile hypertrophic pyloric stenosis (IHPS) 2, 3
• Infants receiving macrolides should be monitored for IHPS and other serious adverse events 2

Infants 1-5 months

• Azithromycin: 10 mg/kg per day for 5 days 2
• Clarithromycin is also considered a first-line agent based on in vitro effectiveness, safety, and convenient dosing 2

Infants ≥ 6 months and children

• Azithromycin: 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
• Clarithromycin is an acceptable alternative 1

Adults

• Azithromycin: 500 mg on day 1, followed by 250 mg per day on days 2-5 2, 1

Alternative Treatment Options

• For patients aged >2 months with macrolide contraindications, trimethoprim-sulfamethoxazole (TMP-SMZ) is recommended 2
• Erythromycin (40-50 mg/kg/day in 4 divided doses for 14 days in children; 2 g per day in 4 divided doses for 14 days in adults) is effective but has more side effects and requires longer treatment duration 2, 4

Efficacy and Clinical Considerations

• Early antibiotic treatment (during the catarrhal phase, first 2 weeks) is most effective in:
  • Reducing duration and severity of symptoms 2
  • Decreasing coughing paroxysms 2
  • Lessening period of communicability 2
• Short-term antibiotics (azithromycin for 3-5 days) are as effective as long-term (erythromycin for 10-14 days) in eradicating B. pertussis from the nasopharynx 5
• Patients should be isolated at home and away from work or school for 5 days after starting antibiotic therapy 2

Side Effects and Precautions

• Azithromycin and clarithromycin are better tolerated and associated with fewer and milder side effects than erythromycin 2
• Common side effects of macrolides include:
  • Gastrointestinal symptoms (nausea, vomiting, abdominal pain, diarrhea) 2, 3
  • These side effects are more frequent and severe with erythromycin 2
• Azithromycin should not be taken with aluminum- or magnesium-containing antacids as they reduce absorption 2, 1
• Macrolides are contraindicated in patients with history of hypersensitivity to any macrolide agent 2

Postexposure Prophylaxis

• The same antimicrobial agents and dosing regimens used for treatment are recommended for postexposure prophylaxis 2, 1
• Prophylaxis should be administered to close contacts, especially in exposure settings that include:
  • Infants aged <12 months 2
  • Women in the third trimester of pregnancy 2, 1

Clinical Course and Prognosis

• Approximately 80-90% of patients with untreated pertussis will spontaneously clear B. pertussis from the nasopharynx within 3-4 weeks from onset of cough 2
• Untreated and unvaccinated infants can remain culture-positive for >6 weeks 2
• While antibiotics effectively eliminate B. pertussis from the nasopharynx, they may not significantly alter the subsequent clinical course if started late in the disease 5