Which factor is most likely to affect medication absorption in older adults?

In older adults, multiple physiological changes can significantly impact how medications are absorbed in the body. Each of the factors listed plays a role:

Increased body fat is relevant because many medications are lipophilic, meaning they can be stored in fat tissue. With age, the proportion of body fat tends to increase, which can alter the distribution of these drugs and subsequently affect their absorption and effectiveness.

Decreased blood flow can result from various age-related conditions and can also influence medication absorption. Poor circulation may reduce the delivery of drugs to the tissues and organs where they are needed, leading to slower absorption rates.

Changes in gastrointestinal pH are particularly important for drugs that require a specific pH level for optimal absorption. As people age, the stomach’s acid production often decreases, which can affect how well certain medications dissolve and are absorbed.

Given that all these factors can independently affect medication absorption, it's accurate to conclude that all of them collectively contribute to the challenges faced in pharmacology for older adults. Therefore, the answer encompasses the broad range of changes influencing absorption in this demographic.