Azithromycin is one of the antibiotics you may be using. It belongs to macrolides class of antibiotics and can stimulate the motilin receptors of GIT and cause loose stools and diarrhoea.
Once you have completed the course of azithromycin 500, the symptoms will slowly fade off
Till then ,take adequate hydration to makeup for the lost volume.
You can do further evaluation if still confused
Next Steps
adequate hydration
consult for further evaluation