Most bacterial infections in animals are treatable, thanks to antibiotics. But be aware that some antibiotics can have side effects.

Rhodococcus equi [ROAD-o-coccus eck-we] are bacteria that can cause pneumonia in young foals. Fortunately, macrolide antibiotics — like erythromycin [earth-row-MY-a-sin] — provide effective treatment, and most foals tolerate them well. However, some foals develop drug-induced diarrhea, respiratory distress and a high body temperature called hyperthermia. That’s because drugs like erythromycin, azithromycin and clarithromycin can compromise a foal’s ability to sweat. What’s more, macrolide-induced hyperthermia can last for several weeks beyond treatment.

That’s why foals on macrolide therapy should stay in a cool area and out of direct sunlight until three weeks after treatment ends. The goal is to support both effective — and safe — treatment.