Dear Madam, Hi & Welcome. I appreciate your concern for your beloved son and I am sorry to know about his motorbike accident a couple of years ago which could have caused his present problems. Tramil (Paracetamol & Caffeine) is a pain reliever generally prescribed for the short term treatment of headaches, migraine, backache, rheumatic pain, muscle pain, toothache and for relieving fever. Generally it is a safe medication. However it may cause allergic reactions. Very rarely it may decrease red blood cells and platelet counts. In larger doses, liver damage may occur due to increased intake of Paracetamol and high caffeine intake can result in tremor and palpitations. As far as his painful swelling in the knee is concerned, he needs to be evaluated by an orthopedic surgeon and to rule out certain post-traumatic conditions like arthritis, osteomyelitis (infection of the bone) or tumor involving the knee joint. Hope the advice given above would be useful. Best regards. A feed back is appreciated.