Article by The U.S. Food and Drug Administration
“As you get older you may be faced with more health conditions that you need to treat on a regular basis. It is important to be aware that more use of medicines and normal body changes caused by aging can increase the chance of unwanted or maybe even harmful drug interactions. The more you know about your medicines and the more you talk with your health care professionals, the easier it is to avoid problems with medicines.
As you get older, body changes can affect the way medicines are absorbed and used. For example, changes in the digestive system can affect how fast medicines enter the bloodstream. Changes in body weight can influence the amount of medicine you need to take and how long it stays in your body. The circulatory system may slow down, which can affect how fast drugs get to the liver and kidneys. The liver and kidneys also may work more slowly, affecting the way a drug breaks down and is removed from the body.”