Normally, you may be instructed to take something with or without milk (or food or lots of water, etc) by your doctor. I have been told to take certain medications with milk to protect my stomach (the medication was known to be irritating to the stomach). That’s all I know. Nothing about effectiveness, more just to do with if your digestive system should be started up or not, if your stomach lining needs protection or not, etc.
Now, why milk should not be mixed with the drug? Drugs or antibiotics consumed orally can be effective for a person if consumed and absorbed by the body. Oral medication must be absorbed through the digestive tract so that it can enter the bloodstream and sent to hurt area. There are several factors that affect the body’s ability to absorb medications very well, including the relative acidity in the stomach, the presence or absence of fat nutrients or other nutrients, and whether there are certain elements such as calcium. Some drugs in the family of antibiotics, containing tetracycline that will react with the milk.
Calcium which is found in milk will bind drugs or antibiotics that prevent absorption into the body. In addition, there is a good drug consumed before and after meals. This is because the food you eat can affect drug absorption. Therefore, the best thing to do is follow the instructions written on the package and don’t forget to ask the pharmacist if necessary.
So the best thing is to take medicines with fresh water because water does not contain compounds that could interfere drugs absorption.