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Mechanism of action of paracetamol
Paracetamol, more commonly known as Tylenol, has a distinct mechanism of action but the full system of its pain impeding action is still unknown to pharmacological experts. Therefore, it is often classified as a non-NSAID drug. However, physicians also class it as a non-opioid analgesic. It cannot be put into both these classes because the mechanism of its action is somewhat different, even though the extent of the clinical effect is almost similar.
The drug works by inhibiting the cyclooxygenase pathway and affects the central nervous system, thereby mitigating the sense of pain and increasing its threshold. It inhibits two cyclooxygenase enzymes, COX-1 and COX-2. Both of these enzymes are involved in synthesizing prostaglandins in the body. Prostaglandins are the biomolecules that enable the sensation of pain. Paracetamol does not inhibit the pathway of cyclooxygenase in the peripheral parts of the body, so the effects are observed in the central areas only. Furthermore, because Paracetamol inhibits the cyclooxygenase pathway indirectly, it does not cause irreversible inhibition, which is more preferred than the mechanism of action induced by NSAIDs.
The unique property of Paracetamol is that it blocks the variant types of COX-1 and COX-2 enzymes very selectively, making the effect different from other analgesics. Latest studies also show that the enzyme inhibited by acetaminophen is COX-3 and not COX-1 or COX-2. In addition, Paracetamol regulates the temperature in the body by controlling the heat-regulating centers in the brain. This causes vasodilation in the peripheral areas of the body and induces sweat, bringing down the patient’s temperature just as the onset of action of the drug takes place.
