Gabapentin enacarbil

The most common side effects of gabapentin enacarbil are:

• dizziness,
• somnolence,
• ataxia,
• fatigue, and
• drowsiness.

Gabapentin enacarbil may cause significant driving impairment. Fluid retention, hostility, nausea and vomiting also occur. Other adverse events associated with gabapentin enacarbil include:

• weight gain,
• joint pain,
• motion sickness,
• blurred vision, and
• viral infections.

Gabapentin enacarbil is converted to gabapentin, which is an anti-seizure medication. Anti-seizure medications have been associated with an increased risk of suicidal thinking and behavior. Anyone considering the use of anti-seizure drugs must balance this risk of suicide with the clinical need. Patients who are started on therapy should be closely observed for clinical worsening, suicidal thoughts, or unusual changes in behavior.

Dosage Forms & Strengths

tablet, extended-release

• 300mg
• 600mg

Restless Leg Syndrome (RLS)

Indicated for moderate-to-severe primary restless legs syndrome

600 mg qDay with food at about 5:00 pm

Postherpetic neuralgia

600 mg PO x3 days, and then increase to 600 mg PO BID

Renal Impairment

CrCl >60 mL/min: 600 mg qDay

CrCl 30-59 mL/min: Start at 300 mg qDay; if needed may increase to 600 mg qDay

CrCL 15-29 mL/min: 300 mg qDay

CrCl <15 mL/min: 300 mg every other day

CrCl <15 mL/min and hemodialysis: Do not administer

Administration

Swallow tablet whole, do not cut, crush, or chew

Take with food

If dose not taken as scheduled, wait until next scheduled dose to resume administration

Discontinuation: Gradually taper downward; patients receiving 600 mg BID for postherpetic neuralgia should decrease dose to 600 mg qDay for 1 week

Safety and effectiveness have not been studied

May require a dose reduction depending on renal function (see Renal Impairment)

Postherpetic Neuralgia (Horizant)

600 mg PO x3 days, and then increase to 600 mg PO BID

Restless legs syndrome (Horizant)

Indicated for moderate-to-severe primary restless legs syndrome

600 mg PO qDay with food at about 5 PM

• It is used to treat restless leg syndrome.
• It is used to treat painful nerve diseases.
• It may be given to you for other reasons. Talk with the doctor.

• If you have an allergy to gabapentin or any other part of gabapentin enacarbil.
• If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
• If you have restless leg syndrome and you need to sleep during the daytime and stay awake at night.
• If you are on dialysis, talk with your doctor.
• If you are taking another drug that has the same drug in it.
• If you are breast-feeding or plan to breast-feed.

This is not a list of all drugs or health problems that interact with this medicine.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take gabapentin enacarbil with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

• Tell all of your health care providers that you take this medicine. This includes your doctors, nurses, pharmacists, and dentists.
• Avoid driving and doing other tasks or actions that call for you to be alert until you see how gabapentin enacarbil affects you.
• Have blood work checked as you have been told by the doctor. Talk with the doctor.
• Avoid drinking alcohol while taking this medicine.
• Talk with your doctor before you use other drugs and natural products that slow your actions.
• This medicine is not the same as gabapentin (Gralise™, Neurontin®). Do not use in its place. Talk with your doctor.
• A very bad and sometimes deadly reaction has happened with gabapentin enacarbil. Most of the time, this reaction has signs like fever, rash, or swollen glands with problems in body organs like the liver, kidney, blood, heart, muscles and joints, or lungs. Talk with the doctor.
• Do not stop taking this medicine all of a sudden without calling your doctor. You may have a greater risk of side effects. If you need to stop gabapentin enacarbil, you will want to slowly stop it as ordered by your doctor.
• If you are 65 or older, use this medicine with care. You could have more side effects.
• Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using gabapentin enacarbil while you are pregnant.

Use this medicine as ordered by your doctor. Read all information given to you. Follow all instructions closely.

• Take gabapentin enacarbil with food.
• Swallow whole. Do not chew, break, or crush.
• For restless leg syndrome, take about 5 PM each day.

What do I do if I miss a dose?

• Skip the missed dose and go back to your normal time.
• Do not take 2 doses at the same time or extra doses.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Dizziness.
• Feeling sleepy.
• Headache.
• Upset stomach.
• Feeling tired or weak.
• Not able to sleep.
• Weight gain.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

Adverse events were observed in animal reproduction studies. Gabapentin enacarbil is the prodrug of gabapentin; bioavailability following gabapentin enacarbil is increased in comparison to gabapentin (Backonja, 2011). Refer to Gabapentin monograph for information related to gabapentin exposure during pregnancy.

Applies to gabapentin enacarbil: oral tablet extended release

Along with its needed effects, gabapentin enacarbil may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking gabapentin enacarbil:

• Bloating or swelling of the face, arms, hands, lower legs, or feet
• discouragement
• feeling sad or empty
• irritability
• lack of appetite
• loss of interest or pleasure
• rapid weight gain
• tingling of the hands or feet
• tiredness
• trouble concentrating

• Black, tarry stools
• bloody or cloudy urine
• changes in behavior
• chest pain or discomfort
• chills or fever
• confusion
• difficulty with breathing
• dizziness or lightheadedness
• fainting
• fast heartbeat
• nausea or vomiting
• painful or difficult urination
• rapid, shallow breathing
• rash
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• swelling of the face, feet, or lower legs
• swollen, painful, or tender lymph glands in the neck, armpit, or groin
• thoughts of killing oneself
• unusual bleeding or bruising
• upper right abdominal or stomach pain
• yellow eyes and skin

Some side effects of gabapentin enacarbil may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

• Lack or loss of strength
• sleepiness or unusual drowsiness

• Blurred vision
• decreased interest in sexual intercourse
• dry mouth
• excess air or gas in the stomach or intestines
• inability to have or keep an erection
• sensation of spinning
• weight gain