Infen Plaster is a pain-relieving medicine. It is used to treat pain, swelling, stiffness, and joint pain in conditions like rheumatoid arthritis, osteoarthritis, and acute musculoskeletal injuries. It works by blocking the release of certain chemical messengers that cause fever, pain, and inflammation. Your doctor will explain how to use Infen Plaster. Follow the instructions carefully to get the most benefit. The dose and duration will depend on what you are using it for and how well it helps your symptoms. Use it regularly and do not discontinue using it until the doctor tells you to stop using it.The most common side effect of this medicine is application site reactions such as redness and swelling. These are usually mild and resolve with time. If they do not go away or bother you, you should remove your patch and contact your doctor.Before using the medicine, you should tell your doctor if you have any other illnesses or disorders. It may also affect, or be affected by some other medicines you are using. Let your doctor know all the other medicines you are taking or using to make sure it is safe for you. Pregnant and breastfeeding women should consult their doctors first before using the medicine.