Which medication is the drug of choice for managing a cough in an infant suspected of having pertussis?

The drug of choice for managing a cough in an infant suspected of having pertussis is azithromycin. Pertussis, also known as whooping cough, is a highly contagious respiratory disease caused by the bacterium Bordetella pertussis. Azithromycin is effective against this bacteria and is commonly used for treatment, particularly in infants and young children, to help reduce the severity of the disease and prevent its spread.

Treatment with azithromycin can help alleviate symptoms and is critical in preventing complications associated with pertussis, especially in the infant population where the risk for severe disease is higher. Early intervention with appropriate antibiotics like azithromycin is crucial, as this can mitigate the transmission of the bacteria and decrease the associated risks in young patients.

Other options, such as ceftriaxone, ampicillin, and gentamicin, do not target the specific organism responsible for pertussis and therefore are not suitable choices for managing this condition in an infant. They are used to treat different types of bacterial infections but lack efficacy against B. pertussis.