What is the recommended treatment for an 11-year-old patient with pertussis?

Treatment of Pertussis in an 11-Year-Old Patient

Azithromycin is the recommended first-line treatment for an 11-year-old patient with pertussis, with a dosing regimen of 10 mg/kg (maximum: 500 mg) on day 1, followed by 5 mg/kg per day (maximum: 250 mg) on days 2-5. 1

First-Line Treatment Options

• Azithromycin is preferred over other macrolides due to its effectiveness, better tolerability, and shorter treatment duration (5 days versus 14 days for erythromycin) 1, 2
• For children aged ≥6 months (including our 11-year-old patient), the recommended azithromycin dosing is 10 mg/kg (maximum: 500 mg) on day 1, followed by 5 mg/kg per day (maximum: 250 mg) on days 2-5 3, 1
• Azithromycin has been demonstrated to be as effective as erythromycin for bacterial eradication (100% efficacy) while causing significantly fewer gastrointestinal side effects 2

Alternative Treatment Options

• Clarithromycin can be used as an alternative first-line agent with a dosing regimen of 7.5 mg/kg twice daily for 7 days 3, 1
• Erythromycin, while effective, is less preferred due to:
  • Longer treatment duration (14 days) 3, 4
  • Higher incidence of gastrointestinal side effects (41.2% vs 18.8% for azithromycin) 2
  • Lower compliance rates (55% vs 90% for azithromycin) 2, 5
• For patients with macrolide contraindications, trimethoprim-sulfamethoxazole (TMP-SMZ) can be used if the patient is >2 months of age 1

Treatment Timing and Effectiveness

• Antibiotics administered early in the course of illness can reduce the duration and severity of symptoms and decrease the period of communicability 3, 1
• Treatment primarily aims to eradicate B. pertussis from the nasopharynx, rendering the patient non-infectious 3, 4
• Even without treatment, approximately 80-90% of patients will spontaneously clear B. pertussis from the nasopharynx within 3-4 weeks from onset of cough 3

Important Considerations and Precautions

• Macrolides are contraindicated in patients with a history of hypersensitivity to any macrolide agent 3, 1
• Azithromycin should not be taken with aluminum- or magnesium-containing antacids as they reduce absorption 3, 1
• Monitor for potential side effects, which may include:
  • Gastrointestinal symptoms (abdominal discomfort, diarrhea, nausea, vomiting) 3, 2
  • Headache and dizziness 3

Post-Exposure Prophylaxis for Close Contacts

• The same antimicrobial agents and dosing regimens used for treatment are recommended for post-exposure prophylaxis of close contacts 3, 1
• Post-exposure prophylaxis should be administered to close contacts within 21 days of exposure, particularly in settings that include:
  • Infants <12 months of age 3, 6
  • Women in the third trimester of pregnancy 3, 1
  • Household contacts 6

Prevention Through Vaccination

• Vaccination remains the most important preventive strategy against pertussis 3, 6
• Immunity from vaccination wanes after 5-10 years, making previously vaccinated individuals (like our 11-year-old patient) potentially susceptible to infection 3, 6
• Ensure the patient is up-to-date with pertussis vaccination to prevent future infections 3, 7