I think we don't need Ajax here. we just need to load the drugs list (~400 drugs) one time, and then put it into a store. Then, we just pull in the whole store and filter based on typed letters (as done in OPD "autocomplete").
Would be helpful
In this , we need to call Ajax every time , as we need updated list of drugs , as users can enter the new drugs , which we could fetch only from our db , so putting all drugs in store , may be not that efficient for here .