If there is persistence or even aggravation of the symptoms within 2 days after the injection, it is not recommended to treat again with tulathromycin, as written in the Statistical Process Control (SPC):
For any respiratory disease, it is recommended to treat animals in the early stages of the disease and to evaluate the response to treatment within 48 hours after injection. If clinical signs of respiratory disease persist or increase, or if relapse occurs, treatment should be changed using another antibiotic and continued until clinical signs have resolved.
Conversely, it remains possible to reinject TULISSIN(R) to an animal previously cured, for instance to treat another outbreak of disease. In this case, we recommend to wait at least 2 weeks between the 2 successive injections, due to the very long action of TULISSIN(R) Injection.