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 adolescent we all have been using medicines for different health related issues. At times when we are sick and go to the doctor for health check-up, we are prescribed certain medicines which when consumed makes us feel better in sometime, whether it is for fever, cough, cold or any other ailment.

Have you ever pondered upon how medicines work in our body? Well, how medicines work is a mystery for at least for all those who have not studied about 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 which will help us understand the process of how medicines work from start to finish. We can understand pharmacokinetics (how 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 body’s circulation from the site of administration. Few of the common way for intake of drugs are oral (swallowing a tablet), intramuscular (taking injection shot in muscle), subcutaneous (under the skin like insulin), intravenous (through vein) or transdermal (Wearing a skin patch). Medicines taken through 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 is absorption in the body, the next step in the process is distribution. After body receives a medicines inside, it is carried in the body through blood stream. 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 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 distribution of medicine, process of breaking medicine or metabolism takes place. The medicine that enters the blood stream 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, 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 faeces. 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.