You should not stop regular medication or supplements before taking the test - it is important to follow your usual routine as otherwise your sample might not be reflective of your microbiome in the state that is most representative of what is normal for you.
Antibiotics is also a special case - if you are using these long term, they would need to be continued but if taking a short course for a specific infection, you would need to wait 4-8 weeks for your microbiome to recover.
We have specific guidance on supplements known to affect the gut microbiome:
https://support.biomesight.com/kb/sample-collection/should-i-take-a-break-from-taking-probiotics-fermented-foods-and-prebiotics-before-i-collect-my-sample
https://support.biomesight.com/articles/do-i-need-to-stop-immunoglobulins-before-collecting-my-sample