If you have epilepsy, it means that you have had more than one unexplained fit, or seizure. A seizure is a short episode of symptoms caused by a burst of abnormal electrical activity in your brain. Different parts of the brain control different functions of your body, so the symptoms that occur during a seizure will depend on where the abnormal burst of electrical activity occurs. Symptoms that may occur during a seizure can affect your muscles, sensations, behaviour, emotions, consciousness, or a combination of these. The seizures can be prevented in most people by suitable antiepileptic medication. Phenytoin is a commonly used medicine. It works by stabilising the electrical activity of your brain, which prevents the seizures from occurring. Phenytoin is also prescribed as a treatment for severe burning or stabbing pains in the face, a nerve pain called trigeminal neuralgia. This is because it can modify some types of pain. If you have been given phenytoin for this reason, ask your doctor if you have questions about your treatment. Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you (or your child if you are their carer) start taking phenytoin it is important that your doctor knows:
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with phenytoin. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.
Important: your doctor will discuss with you the possibility that phenytoin can cause blood and skin disorders. Although these occur less commonly than the side-effects listed above, it is important that you contact your doctor straightaway if you experience any of the following symptoms:
If you experience any other symptoms which you think may be due to phenytoin, speak with your doctor or pharmacist for further advice.
Headache, nausea, vomiting, constipation, dizziness, feeling of spinning, drowsiness, trouble sleeping, or nervousness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. Phenytoin may cause swelling and bleeding of the gums. Massage your gums and brush and floss your teeth regularly to minimize this problem. See your dentist regularly. Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: slow heartbeat, unusual eye movements, loss of coordination, trouble speaking, confusion, muscle twitching, double or blurred vision, tingling of the hands/feet, facial changes (such as swollen lips, butterfly-shaped rash around the nose/cheeks), excessive hair growth, increased thirst or urination, unusual tiredness, bone or joint pain, easily broken bones. A small number of people who take anticonvulsants for any condition (such as seizure, bipolar disorder, pain) may experience depression, suicidal thoughts/attempts, or other mental/mood problems. Tell your doctor right away if you or your family/caregiver notice any unusual/sudden changes in your mood, thoughts, or behavior including signs of depression, suicidal thoughts/attempts, thoughts about harming yourself. Rarely, males may have a painful or prolonged erection lasting 4 or more hours. If this occurs, stop using this drug and get medical help right away, or permanent problems could occur. Get medical help right away if you have any very serious side effects, including: uncontrolled muscle movements, signs of liver problems (such as nausea/vomiting that doesn't stop, stomach/abdominal pain, yellowing eyes/skin, dark urine), easy bruising/bleeding. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: fever, swollen lymph nodes, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345. |