Fentrans 25mcg Transdermal Patch is a pain-relieving medicine. It is used to manage persistent, moderate to severe chronic pain that requires continuous, around-the-clock opioid administration for an extended period of time. Your doctor will explain how to use Fentrans 25mcg Transdermal Patch. 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 it is alright to stop. The most common side effects of this medicine include headache, dizziness, vomiting, nausea, abdominal pain, and irregular heartbeat. You may have side effects more often when you start your treatment or when your dose is increased. Usually, the side effects will slowly go away as your body gets used to it. If they are severe or do not go away, 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 drugs you are using so let your doctor know what these are to be safe. Pregnant and breastfeeding women should consult their doctors first before using the medicine.