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Ibuprofen belongs to a group of medicines know as Non-Steroidal Anti-Inflammatory Drugs (NSAIDs). It was discovered by Dr Stewart Adams and his colleagues John Nicolson and Colin Burrows who all worked for Boots Pure Drug Company in Nottingham, England. They were looking for a possible replacement drug for aspirin and they tested each new compound by evaluating the way that the anti-inflammatory drug reduced the erythema caused by ultra violet light on the skin. After screening many drugs for their potential therapeutic activity clinical trials began on a new compound referred to as BTS8402 but this was eventually found to be unsatisfactory. Dr Adams and his colleagues then discovered a group of compounds known as phenylalkanoic acids which also possessed antipyretic, analgesic and anti-inflammatory properties. This included ibuprofen, or 2-(4-isobutylphenyl) propionic acid, which has subsequently become one of the most popular painkillers throughout the world.In 1966, the first clinical trials for ibuprofen were held in Edinburgh, Scotland by Dr Tom Chambers. Ibuprofen was not the most biologically active of the phenylpropionic acids discovered but it was considered to be the safest compound with the fewest side effects. It is gentler on the stomach than aspirin and as easily tolerated as paracetamol by the body. These trials clearly demonstrated that ibuprofen reduced swelling, alleviating tenderness and stiffness in the joints. When use an anti-inflammatory, ibuprofen was found to be between 16 and 32 times as effective as similar dosages of aspirin. Its analgesic properties were found to be about 30 times as effective as aspirin, while its antipyretic attributes were up to 20 times more effective. In 1969, Boots made ibuprofen available for prescription use in the United Kingdom as a treatment for rheumatoid arthritis, with the United States following suit in 1974.Ibuprofen provides pain relief by preventing the release of an enzyme called cyclo-oxygenase (COX). Cyclo-oxygenase is responsible for the production of various other chemicals by the body, including those known as prostaglandins which are found in all inflamed tissue. These prostaglandins consist of a group of about a dozen compounds that are synthesized from fatty acids. Prostaglandins are manufactured as a response to injury or damage and cause pain, inflammation or swelling at the site of an injury in order to convey this damage to the body. The special nerve endings that transmit the pain message to the brain are very sensitive to prostaglandin and respond with information on where the pain is located and its severity. Ibuprofen inhibits the cells from producing prostaglandin so the brain does not receive the pain message as quickly or as clearly.Ibuprofen will relieve the pain associated with complaints such as headache, migraine headache, backache, neuralgia, rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, muscular aches, soft-tissue injuries like tendonitis or bursitis, sprains and strains, surgical pain, dental pain, rheumatic pain, period pain (primary dysmenorrhea) and menstrual cramps. It does not, however, treat the cause of the condition but only the pain that is the body's response to it.Ibuprofen can also reduce the symptoms of colds and flu, including inflammation, sore throat and fever (pyrexia). Because several prostaglandins have been shown to participate in the temperature-regulating mechanisms in the hypothalamus, this enables ibuprofen to reduce fever by making adjustments to the brain's thermostatic control over the body's temperature. Ibuprofen will usually provide effective pain relief within 30 minutes of being taken, peaking after 1 to 2 hours. Ibuprofen is composed of carbon, hydrogen, and oxygen, and is usually excreted out of the body through urination within twenty-four hours of being taken.