[Posted 06/16/2015] ISSUE: Based on reviews of additional safety reports from patients treated with the anti-seizure drug ezogabine (Potiga), the FDA has determined that the potential risks of vision loss due to pigment changes in the retina and of skin discoloration can be adequately managed by following the current recommendations in the ezogabine labeling. To further explore any potential long-term consequences of these pigment changes, FDA has required the ezogabine manufacturer, GlaxoSmithKline, to conduct a long-term observational study.
FDA review of additional safety reports does not indicate that the pigment changes in the retina observed in some patients affect vision. Skin discoloration associated with the use of ezogabine appears to be a cosmetic effect and does not appear to be associated with more serious adverse effects. Therefore, a modification of the Risk Evaluation and Mitigation Strategy (REMS) is not needed at this time to ensure that the benefits of ezogabine outweigh the risks of retinal and skin pigment changes. FDA expects that the required long-term observational study will provide further information on whether pigment changes in the retina caused by ezogabine can lead to vision loss or other long-term side effects. In addition, the study should provide more information on the relationship between pigment changes in the retina and skin discoloration.
BACKGROUND: Ezogabine is approved for use in combination with other anti-seizure drugs to treat partial-onset seizures in adult patients who have had an inadequate response to several alternative therapies and for whom the benefits of treatment outweigh the risks.
RECOMMENDATION: Health care professionals should continue to follow the recommendations provided in the Boxed Warning, FDA's most serious type of warning, and the Warnings and Precautions and Indications and Usage sections of the labeling. For more information visit the FDA website at: http://www.fda.gov/Safety/MedWatch/SafetyInformation and http://www.fda.gov/Drugs/DrugSafety.
Why is this medication prescribed?
Ezogabine is used along with other medications to control partial onset seizures (seizures that involve only one part of the brain) in adults. Ezogabine is in a class of medications called anticonvulsants. It works by reducing abnormal electrical activity in the brain.
How should this medicine be used?
Ezogabine comes as a tablet to take by mouth. It is usually taken with or without food three times a day. Take ezogabine at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand.
Swallow the tablets whole; do not split, chew, dissolve, or crush them.
Your doctor will probably start you on a low dose of ezogabine and gradually increase your dose, not more than once every week.
Take ezogabine exactly as prescribed. Ezogabine may be habit forming. Do not take a larger dose, take it more often, or take it for a longer period of time than prescribed by your doctor.
Ezogabine may help control your condition but will not cure it. It may take a few weeks or longer before you feel the full benefit of ezogabine. Continue to take ezogabine even if you feel well. Do not stop taking ezogabine without talking to your doctor, even if you experience side effects such as unusual changes in behavior or mood. If you suddenly stop taking ezogabine, your seizures may happen more often. Your doctor will probably decrease your dose gradually over at least 3 weeks.
Your doctor or pharmacist will give you the manufacturer's patient information sheet (Medication Guide) when you begin treatment with ezogabine and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) or the manufacturer's website to obtain the Medication Guide.
Other uses for this medicine
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?
Before taking ezogabine,
- tell your doctor and pharmacist if you are allergic to ezogabine, any other medications, or any of the ingredients in ezogabine tablets. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
- tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: amiodarone (Cordarone, Pacerone); certain antibiotics such as azithromycin (Zithromax), clarithromycin (Biaxin), erythromycin (E.E.S., Erythrocin), or moxifloxacin (Avelox); chloroquine (Aralen); antihistamines; carbamazepine (Carbatrol, Epitol, Equetro, Tegretol, Teril), chlorpromazine; citalopram (Celexa); digoxin (Cardoxin, Digitek, Lanoxicaps, Lanoxin); disopyramide (Norpace); dofetilide (Tikosyn); droperidol (Inapsine); flecainide (Tambocor); haloperidol (Haldol); ipratropium (Atrovent); medications for irritable bowel disease, motion sickness, Parkinson's disease, ulcers, or urinary problems; mesoridazine (Serentil); methadone (Dolophine); pentamidine (NebuPent, Pentam); phenytoin (Dilantin, Phenytek); pimozide (Orap); procainamide (Pronestyl); quinidine (in Nuedexta); sotalol (Betapace); thioridazine; and vandetanib (Caprelsa). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you drink or have ever drunk large amounts of alcohol and if you have or have ever had benign prostatic hyperplasia (BPH; enlarged prostate) or any other condition that causes difficulty urinating, heart failure or other heart problems, a long QT interval (a heart problem that may cause irregular heartbeat, fainting, or sudden death), low levels of potassium or magnesium in your blood, or kidney or liver disease.
tell your doctor if you are pregnant, plan to become pregnant or are breastfeeding. If you become pregnant while taking ezogabine, call your doctor.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking ezogabine.
- you should know that ezogabine may make you dizzy, drowsy, confused, or unable to concentrate. Do not drive a car or operate machinery until you know how this medication affects you.
- ask your doctor about the safe use of alcoholic beverages while you are taking ezogabine. Alcohol can make the dizziness and drowsiness caused by ezogabine worse.
- you should know that your mental health may change in unexpected ways and you may become suicidal (thinking about harming or killing yourself or planning or trying to do so) while you are taking ezogabine for the treatment of epilepsy or other conditions. A small number of adults and children 5 years of age and older (about 1 in 500 people) who took anticonvulsants such as ezogabine to treat various conditions during clinical studies became suicidal during their treatment. Some of these people developed suicidal thoughts and behavior as early as one week after they started taking the medication. There is a risk that you may experience changes in your mental health if you take an anticonvulsant medication such as ezogabine, but there may also be a risk that you will experience changes in your mental health if your condition is not treated. You and your doctor will decide whether the risks of taking an anticonvulsant medication are greater than the risks of not taking the medication. You, your family, or your caregiver should call your doctor right away if you experience any of the following symptoms: panic attacks; agitation or restlessness; new or worsening irritability, anxiety, or depression; acting on dangerous impulses; difficulty falling or staying asleep; aggressive, angry, or violent behavior; mania (frenzied, abnormally excited mood); talking or thinking about wanting to hurt yourself or end your life; withdrawing from friends and family; preoccupation with death and dying; giving away prized possessions; or any other unusual changes in behavior or mood. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.
What special dietary instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do if I forget a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?
Ezogabine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- problems with coordination, balance, or walking
- memory problems
- drowsiness, confusion, or trouble concentrating
- difficulty or inability to speak or understand speech or written language
- feelings of numbness, tingling, pricking, burning, or creeping on the skin
- uncontrollable shaking of a part of the body
- abnormal color of urine
- weight gain
Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:
- inability to begin urinating
- changes in color (blue) of skin, lips, or fingernails
- changes in vision
- pain when urinating
- weak urine stream
- difficulty emptying your bladder
- blood in urine
- difficulty thinking clearly, understanding reality, or using good judgment
- hallucinations (seeing things or hearing voices that do not exist)
Ezogabine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).
What should I know about storage and disposal of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
Store ezogabine in a safe place so that no one else can take it accidentally or on purpose. Keep track of how many tablets are left so you will know if any are missing.
In case of emergency/overdose
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include the following:
- aggressive behavior
- irregular heartbeat
What other information should I know?
Your doctor will probably order regular eye examinations while you are taking this medication. Keep all appointments with your doctor and eye doctor.
Do not let anyone else take your medication. Ezogabine is a controlled substance. Prescriptions may be refilled only a limited number of times; ask your pharmacist if you have any questions.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.