ADME: How Your Body Absorbs, Distributes, Metabolizes, and Excretes Medications

When you take a pill, it doesn’t just disappear and start working. It goes through a hidden process called ADME, the four-step journey your body takes to handle every medication: absorption, distribution, metabolism, and excretion. Also known as pharmacokinetics, it’s the reason why two people taking the same drug can have completely different results. This isn’t just science—it’s the reason your warfarin dose needs checking, why probiotics must be spaced from antibiotics, and why some generics don’t work the same for you as the brand name.

Let’s break it down simply. Absorption, how the drug enters your bloodstream—can be slowed by food, especially protein, which blocks drugs like levodopa. Distribution, how the drug travels through your body affects whether it reaches your brain, kidneys, or joints. That’s why some drugs cause drowsiness while others trigger sweating—where they go determines what they do. Metabolism, mostly in the liver, breaks the drug down. If your liver is slow, the drug builds up and can become toxic. That’s why NTI drugs like lithium and digoxin need close monitoring—they have almost no safety margin. Finally, Excretion, how your body gets rid of the drug, usually through the kidneys. If your kidneys aren’t working well, even normal doses can become dangerous.

These four steps explain why drug interactions happen. NSAIDs and warfarin? The NSAID changes how warfarin is metabolized, increasing bleeding risk. Antidepressants causing sweating? That’s an off-target effect tied to how the drug distributes and interacts with nerve receptors. Even fiber supplements can interfere with absorption if taken too close to your meds. Every post in this collection connects back to ADME—it’s the invisible engine behind every side effect, interaction, and dosing rule you’ve ever heard about.

You won’t find a textbook here. What you’ll find are real stories from people who learned the hard way—why spacing probiotics matters, why switching generics can backfire, how protein in your breakfast ruins your Parkinson’s meds, and why some people need brand-name drugs even when generics are cheaper. These aren’t abstract concepts. They’re the reason your medication works—or doesn’t. If you’ve ever wondered why your pill behaves differently than your friend’s, this is where the answer lives.