Antibiotics are often recommended as a precautionary measure, even in cases where the clinical course may be unaffected. This is done to limit the spread of infection to infants that may be in close proximity to the infected patient.
If diagnosed in the catarrhal stage, B. pertussis can successfully be treated with the use of macrolide antibiotics, including azithromycin, erythromycin, or clarithromycin. Trimethoprim/sulfamethoxazole (TMP-SMZ) can be used as an alternative agent in patients aged ≥ 2 months who are allergic to macrolides (e.g., azithromycin, erythromycin, clarithromycin), who cannot tolerate macrolides, or who are infected with a rare macrolide-resistant strain of Bordetella pertussis. Table 3 summarizes treatment and dosing for pertussis infection.
Antibiotics administered in the paroxysmal stage have shortened the severity and duration of the disease.
Treatment may commence prior to the availability of test results if clinical history is strongly suggestive or the patient is at risk for severe or complicated disease (e.g., infants). If the patient is diagnosed late (past the infectious period), antibiotics will not alter the course of the illness, and even without antibiotics, the patient should no longer be spreading pertussis.
Table 3. Treatment and Dosing for Pertussis Infection.Age Group
| Azithromycin*
| Erythromycin
| Clarithromycin
| TMP-SMZ
|
< 1 month
| Recommended agent
10 mg/kg per day in a single dose for 5 days
Only limited safety data available | Not preferred. Erythromycin is associated with infantile hypertrophic pyloric stenosis. Use if azithromycin is unavailable 40-50 mg/kg per day in 4 divided doses for 14 days | Not recommended (safety data unavailable)
| Contraindicated for infants aged <2 months (risk for kernicterus)
|
1-5 months
| 10 mg/kg per day in a single dose for 5 days
| 40-50 mg/kg per day in 4 divided doses for 14 days
| 15 mg/kg per day in 2 divided doses for 7 days
| Contraindicated at age <2 months. For infants aged ≥2, TMP 8 mg/kg per day. SMZ 40 mg/kg per day in 2 divided doses for 14 days
|
Infants(aged ≥ 6 months) and children
| 10 mg/kg in a single dose on day 1 the 5 mg/kg per day (maximum 500 mg) on days 2-5
| 40-50 mg/kg per day (maximum 2 g per day) in 4 divided doses for 14 days
| 15 mg/kg per day in 2 divided doses (maximum 1 g per day) for 7 days
| TMP 8 mg/kg per day. SMZ 40 mg/kg per day in 2 divided doses for 14 days
|
Adults
| 500 mg in a single dose on day 1 then 250 mg per day on days 2-5
| 2 g per day in 4 divided doses for 14 days
| 1 g per day in 2 divided doses for 7 days
| TMP 320 mg per day. SMZ 1,600 mg per day in 2 divided doses for 14 days
|
*On March 12, 2013, the Food and Drug Administration (FDA) issued a warning that azithromycin can cause abnormal changes in the electrical activity of the heart that may lead to a potentially fatal irregular heart rhythm in some patients. Due to milder side effects and longer half-life resulting in fewer daily doses, Azithromycin remains one of the recommended drugs for treatment and chemoprophylaxis of pertussis, but an alternative drug should be used for those who have known cardiovascular disease.
