How does it work?
Disprin dispersible tablets contain the active ingredient acetylsalicylic acid, otherwise known as aspirin. (NB. Aspirin is also available without a brand name, ie as the generic medicine.)
Aspirin belongs to a group of medicines called non-steroidal anti-inflammatory drugs (NSAIDs). It works by blocking the action of a substance in the body called cyclo-oxygenase.
Cyclo-oxygenase is involved in the production of various chemicals in the body. These are known as prostaglandins, prostacyclins and thromboxane. By blocking the action of cylo-oxygenase, aspirin prevents the production of these chemicals.
High doses of aspirin (300mg and over) prevent the production of prostaglandins. Prostaglandins are produced in response to injury or certain diseases and would otherwise go on to cause pain, swelling and inflammation. Hence a 300mg dose of aspirin is seen as a pain-relieving dose. Disprin dispersible tablets contain 300mg of aspirin and can be used to relieve pain and inflammation.
Aspirin in low doses, eg 75-100mg, does not have this effect and is used instead as an anti-clotting or blood-thinning agent. Low doses of aspirin prevent the production of thromboxane by blood cells called platelets. Thromboxane is one of the chemicals that causes platelets to clump together and start off the clotting process. Stopping its production therefore reduces the likelihood of clots forming in the blood. Clots in the blood can cause a heart attack or stroke, and low dose aspirin is therefore used to prevent this in people who are at risk. See the factsheets linked at the end of this page for more information about this use of aspirin.
Aspirin is also used in the emergency situation of a heart attack. Anyone who has the symptoms of a heart attack (chest pain, possibly radiating towards the arm or neck, shortness of breath) should take one 300mg aspirin tablet as soon as possible, as this has been shown to increase the chances of surviving a heart attack. This is because the aspirin prevents the blood clot that is blocking the supply of blood to the heart from growing any bigger.