What is NOT true concerning the excretion of medications?

The assertion that the liver plays no role in drug excretion is not true. In pharmacology, drug metabolism and excretion are two crucial processes for the removal of medications from the body. While the kidneys are primarily responsible for the excretion of many drugs through urine, the liver significantly contributes to the biotransformation of drugs, a process known as hepatic metabolism. During this process, the liver modifies drugs, making them easier to eliminate through the kidneys and bile. Therefore, it's essential to understand that while the liver may not directly excrete drugs, its role in drug metabolism profoundly impacts the excretion process.

In contrast, the functionality of the kidneys does influence how quickly medications are excreted, as compromised renal function can lead to decreased drug clearance and potential toxicity. Drug formulation indeed affects excretion rates, as different forms (such as tablets versus extended-release formulations) are designed to dissolve and release medications at different rates. Lastly, age can lead to changes in both renal and hepatic function, impacting the overall excretion rates of medications due to physiological changes that occur with aging.