Treatment for a 17-Year-Old with Possible Pertussis
Azithromycin is the preferred treatment for a 17-year-old with possible pertussis, administered as 500 mg on day 1, followed by 250 mg daily for days 2-5. 1, 2
First-Line Antimicrobial Therapy
- Macrolide antibiotics are the first-line treatment for pertussis, with azithromycin being the preferred agent due to better tolerability, fewer side effects, and shorter treatment duration compared to erythromycin 1, 2
- For a 17-year-old (adult dosing), the recommended azithromycin regimen is 500 mg on day 1, followed by 250 mg daily for days 2-5 1
- Treatment should begin as soon as pertussis is suspected, without waiting for laboratory confirmation, as early therapy is more effective at reducing symptoms and preventing transmission 1, 2
Alternative Treatment Options
- Clarithromycin is an acceptable alternative if azithromycin is unavailable, administered as 500 mg twice daily for 7 days 1, 2
- Erythromycin (2 g per day in 4 divided doses for 14 days) can be used but has more gastrointestinal side effects and requires a longer treatment course, leading to poorer compliance 1, 3
- Trimethoprim-sulfamethoxazole is an alternative for patients with macrolide allergy or intolerance 1, 4
Timing and Effectiveness of Treatment
- Antibiotics are most effective when started during the catarrhal phase (first 1-2 weeks of illness) 1, 2
- Even when started during the paroxysmal phase, antibiotics can still eradicate B. pertussis from the nasopharynx and may reduce severity and duration of symptoms 2, 5
- Without treatment, most patients will spontaneously clear B. pertussis from the nasopharynx within 3-4 weeks from onset of cough 2
Isolation Recommendations
- The patient should be isolated at home and away from school for 5 days after starting antibiotic therapy 1
- This isolation period is crucial to prevent transmission to others, especially vulnerable populations such as infants and pregnant women 1, 6
Post-Exposure Prophylaxis for Close Contacts
- Close contacts of the patient should receive post-exposure prophylaxis (PEP) with the same antibiotics and dosing regimens as for treatment 1, 6
- PEP should be administered within 21 days of exposure to be effective 1, 6
- Household contacts and those at high risk for severe disease (infants, pregnant women in third trimester) should be prioritized for PEP 1, 6
Clinical Considerations and Monitoring
- Adjunctive therapies such as long-acting β-agonists, antihistamines, corticosteroids, and pertussis immunoglobulin have not shown significant benefit in controlling cough paroxysms and are not recommended 1
- Monitor for potential complications including weight loss, sleep disturbance, and secondary bacterial infections 2
- Verify and update vaccination status of the patient and close contacts 2, 6
Treatment Efficacy and Compliance
- Studies show that azithromycin has similar or superior efficacy to erythromycin in eradicating B. pertussis, with eradication rates of 93-100% 7, 8
- Compliance with azithromycin (93%) is significantly higher than with erythromycin (57%) due to fewer side effects, particularly gastrointestinal disturbances 3
- Azithromycin has demonstrated in vitro activity against Bordetella pertussis 9