What antibiotics are recommended for treating Bordetella pertussis (whooping cough) in children and adults?

The organism described is most consistent with Bordetella pertussis (whooping cough) that produces episodic coughing fits with post‑tussive vomiting. First‑line therapy is a macrolide antibiotic. For children the usual regimen is azithromycin 10 mg/kg (maximum 500 mg) given as a single daily dose for 5 days; an equivalent pediatric dose of clarithromycin is 15 mg/kg per day divided every 12 hours for 7 days, and erythromycin can be used at 40–50 mg/kg per day divided every 6 hours for 14 days if the macrolides are unavailable or contraindicated. In adults the standard adult dose of azithromycin is 500 mg once daily for 5 days (or a single 1 g dose), clarithromycin 500 mg twice daily for 7 days, or erythromycin 500 mg four times daily for 14 days. If a patient cannot tolerate macrolides, trimethoprim‑sulfamethoxazole (TMP‑SMX) 8 mg/kg (based on the TMP component) divided twice daily for 7 days is an acceptable second‑line option. Therapy should be started as soon as pertussis is suspected to reduce transmission and to shorten the course of illness, and close contacts should receive prophylactic macrolide treatment as well. Supportive measures (hydration, monitoring for apnea in infants, and avoiding triggers of cough) should be provided alongside the antibiotic regimen.