Ezogabine

Ezogabine is a prescription medication used to treat partial-onset seizures in adults. Ezogabine belongs to a group of drugs called potassium channel openers, which may work by reducing abnormal electrical activity in the brain.

This medication comes in tablet form and is taken three times a day, with or without food.

Common side effects include dizziness, confusion, sleepiness, and tiredness. 

Ezogabine is a prescription medicine that is used with other medicines to treat partial onset seizures in people with epilepsy who are 18 years of age or older.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

• how you respond to this medication
• how you tolerate medication
• your renal function
• your hepatic function

The recommended maintenance dose of ezogabine for the treatment of partial-onset seizures in adults is 200 mg to 400 mg 3 times daily (600 mg to 1,200 mg per day), based on individual patient response and tolerability. The initial dosage should be 100 mg 3 times daily (300 mg per day) and should be increased gradually.

• Ezogabine can cause retinal abnormalities with funduscopic features similar to those seen in retinal pigment dystrophies, which are known to result in damage to the photoreceptors and vision loss.
• Some patients with retinal abnormalities have been found to have abnormal visual acuity. It is not possible to determine whether ezogabine caused this decreased visual acuity.
• The rate of progression of retinal abnormalities and their reversibility are unknown.
• Patients who fail to show substantial clinical benefit after adequate titration should be discontinued from ezogabine.
• All patients taking ezogabine should have baseline and periodic (every 6 months) systematic visual monitoring by an ophthalmic professional. Testing should include visual acuity and dilated fundus photography.
• If retinal pigmentary abnormalities or vision changes are detected, ezogabine should be discontinued unless no other suitable treatment options are available and the benefits of treatment outweigh the potential risk of vision loss. 

April 26, 2013- the FDA issued a safety announcement warning that ezogabine "can cause blue skin discoloration and eye abnormalities characterized by pigment changes in the retina." FDA does not currently know if these changes are reversible. All patients taking ezogabine should have a baseline eye exam, followed by periodic eye exams. FDA is working with the manufacturer to gather and evaluate all available information to better understand these events. FDA will update the public when more information is available."

June 16, 2015- the FDA issued a Drug Information Update stating that a 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.

If, while taking ezogabine, you develop any changes in your vision or any discoloration of your skin, including of your lips and nail beds, you should contact your healthcare provider right away. 

Do not stop ezogabine without first talking to a healthcare provider. Stopping ezogabine suddenly can cause serious problems. Stopping ezogabine suddenly can cause you to have more seizures more often.

Other serious side effects have been reported with ezogabine including:

1. Ezogabine can make it hard for you to urinate (empty your bladder) and may cause you to be unable to urinate. Call your healthcare provider right away if you:

• are unable to start urinating
• have trouble emptying your bladder
• have a weak urine stream
• have pain with urination

2. Ezogabine can cause mental (psychiatric) problems, including:

• confusion
• new or worse aggressive behavior, hostility, anger, or irritability
• new or worse psychosis (hearing or seeing things that are not real)
• being suspicious or distrustful (to doubt what one hears or is told)
• other unusual or extreme changes in behavior or mood

Tell your healthcare provider right away if you have any new or worsening mental problems while using ezogabine.

3. Like other antiepileptic drugs, ezogabine may cause suicidal thoughts or actions in a very small number of people, about 1 in 500.

Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you:

• thoughts about suicide or dying
• attempt to commit suicide
• new or worse depression
• new or worse anxiety
• feeling agitated or restless
• panic attacks
• trouble sleeping (insomnia)
• new or worse irritability
• acting aggressive, being angry, or violent
• acting on dangerous impulses
• an extreme increase in activity and talking (mania)
• other unusual changes in behavior or mood

Suicidal thoughts or actions can be caused by things other than medicines. If you have suicidal thoughts or actions, your healthcare provider may check for other causes.

• Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings.
• Keep all follow-up visits with your healthcare provider as scheduled.

Call your healthcare provider between visits as needed, especially if you are worried about symptoms.

Do not drive, operate machinery, or do other dangerous activities until you know how ezogabine affects you. Ezogabine can cause dizziness, sleepiness, double-vision, and blurred vision.

Ezogabine may cause serious side effects, including:

• See “Drug Precautions”.
• Dizziness and sleepiness. These symptoms can increase when your dose of ezogabine is increased. 
• Changes in your heart rhythm and the electrical activity of your heart.Your healthcare provider should monitor your heart during treatment if you have a certain type of heart disease or take certain medications.

Drinking alcohol during treatment with ezogabine may increase the side effects that you get with ezogabine.

The most common side effects of ezogabine include:

• dizziness
• drowsiness
• sleepiness
• tiredness
• confusion
• spinning sensation (vertigo)
• tremor
• problems with balance and muscle coordination, including trouble with walking and moving
• blurred or double vision
• trouble concentrating
• memory problems
• weakness

Tell your healthcare provider about any side effect that bothers you or that does not go away.

These are not all the possible side effects of ezogabine. Ask your healthcare provider or pharmacist for more information.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Taking ezogabine with certain other medicines can affect each other, causing side effects. Especially tell your healthcare provider if you take:

• digoxin (Lanoxin)
• phenytoin (Dilantin, Phenytek)
• carbamazepine (Carbatrol, Tegretol, Tegretol-XR, Equetro, Epitol)

Know the medicines you take. Keep a list of them to show your doctor and pharmacist when you get a new medicine.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Ezogabine falls into category C. In animal studies, pregnant animals were given this medication and had some babies born with problems. No well-controlled studies have been done in humans, though. Therefore, this medication may be used if the potential benefits to the mother outweigh the potential risks to the unborn child.

If you become pregnant while taking ezogabine, talk to your healthcare provider about registering with the North American Antiepileptic Drug Pregnancy Registry. The purpose of this registry is to collect information about the safety of medicines used to treat seizures during pregnancy. You can enroll in this registry by calling 1-888-233-2334.

Tell your healthcare provider if you are breastfeeding or plan to breastfeed. It is not known if ezogabine passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby if you take ezogabine. You and your healthcare provider should decide if you will take ezogabine or breastfeed. You should not do both.

Drinking alcohol during treatment with ezogabine may increase the side effects that you get with ezogabine.

All patients taking ezogabine should have a baseline eye exam, followed by periodic eye exams.

If, while taking ezogabine, you develop any changes in your vision or any discoloration of your skin, including of your lips and nail beds, you should contact your healthcare provider right away.

This medication is a controlled substance (CV) because it can be abused or lead to drug dependence.