How Medicines Work

How Medicines Work

If you have ever given it a thought, it is amazing how medicines work in our bodies. Why is it so that the medicine for headache goes into our stomach and heals the headache? Since our childhood and adolescence, we all have been using medicines for different health-related issues. At times when we are sick and go to the doctor for a health check-up, we are prescribed certain medicines which when consumed make us feel better in some time, whether it is for fever, cough, cold, or any other ailment.

Have you ever pondered upon how medicines work in our bodies? Well, how medicines work is a mystery for at least for all those who have not studied medicines. In this article, you will get to know how medicines work to heal us from different ailments.

To simplify the understanding, there are 4 steps that will help us understand the process of how medicines work from start to finish. We can understand pharmacokinetics (how the body processes a drug/medicine) according to ADME i.e. Absorption, Distribution, Metabolism, and Excretion.

  • ABSORPTION: Medicines are absorbed after intake when they travel to the body’s circulation from the site of administration. A few of the common ways for the intake of drugs are oral (swallowing a tablet), intramuscular (taking injection shot in muscle), subcutaneous (under the skin like insulin), intravenous (through the vein), or transdermal (wearing a skin patch). Medicines taken through the mouth are transferred via a special blood vessel leading from the digestive tract to the liver, where a large amount of the medicine breaks down. Other routes of drug ignore the liver, entering the bloodstream directly or via the skin or lungs.


  • DISTRIBUTION: After medicines are absorption in the body, the next step in the process is distribution. After the body receives a medicine inside, it is carried in the body through the bloodstream. While this step is happening in the body, side effects can occur when a drug has an effect at a site other than its target site. For a pain reliever, the target organ might be a sore muscle in the arm; but the irritation of the stomach could be a side effect. Drugs destined for the central nervous system face a nearly impossible to cross barricade called the blood-brain barrier that protects the brain from potentially dangerous substances such as poisons or viruses. Other factors that can influence distribution include protein and fat molecules in the blood that can put drug molecules out of commission by latching on them.


  • METABOLISM: After the distribution of medicine, the process of breaking medicine or metabolism takes place. The medicine that enters the bloodstream whether swallowed, injected, inhaled, or absorbed through the skin goes into the liver where is it is twisted, pummelled, cut apart, and transformed by proteins called enzymes. Medicine that will effectively work then goes to its target site after breaking down.


  • EXCRETION: After metabolism, the last stage in the working of medicine is excretion. The inactive drug gets excreted out of the body. Removal of non-active medicine happens through urine or feces. Clinical pharmacologists calculate how a person is processing a drug by measuring the amounts of a drug in urine as well as in blood, checking which the doctors can change the dosage or medicine. For example, if the drug is being excreted relatively quickly, a higher dose may be needed. This is how medicines work.