1 What is Horizant?

Brand: Horizant

Generic: Gabapentin Enacarbil

Horizant is used to treat a condition called restless legs syndrome (RLS). It can be used to treat moderate to severe restless legs syndrome.

RLS is one of the neurological disorders that causes an uncomfortable feeling in the legs, which results in an irresistible desire to move the legs continuously.

Gabapentin enacarbil is also used in the management of a pain syndrome called postherpetic neuralgia. It occurs after the shingles and causes severe pain in the face.

This product is available in following dosage form:

  • Tablet, Extended Release

This drug is only available on a doctor’s prescription.

2 What To Know Before Using

Before using Horizant, you must know all about the risks and complications associated with it. Like any other medicine, Gabapentin Enacarbil has potential side effects. So, the benefits of a drug should always be weighed against its associated risks.

Your doctor will consider these risks before prescribing the drug and will inform you about them.

Following factors should be considered before taking this drug:


If you have had an allergic reaction to this drug in the past, inform your doctor. You should also tell your healthcare provider if you are allergic to any other drugs or food products.

Age specific problems

The data regarding the effects of this medicine specific to the pediatric age group is not yet available because appropriate studies have not been carried out. 

The studies specific to the geriatric age group reveal no significant adverse effect specific to the old age group that would limit its use in elder people.


Regarding the safety of usage of this drug during pregnancy, it comes under “C” category which means that the clinical studies reveal harmful effect to the developing fetus or the relevant trials have not taken place.

Drug Interactions

Certain drugs should not be used together because they can interact inside the body which can have a harmful effect. On the other hand, certain drugs are allowed to be used together. So, you should tell your doctor about any other medications you are taking. If there is a chance of interaction between those two drugs, the doctor may change the dose or may prescribe an alternative drug. 

The use of this drug with orlistat is not contraindicated.

Gabapentin enacarbil should be used cautiously along with following drugs:

  • Magaldrate
  • Dihydroxyaluminum Aminoacetate
  • Aluminum Carbonate, Basic
  • Aluminum Hydroxide
  • Aluminum Phosphate
  • Morphine
  • Dihydroxyaluminum Sodium Carbonate
  • Ginkgo
  • Magnesium Carbonate
  • Magnesium Trisilicate
  • Magnesium Hydroxide
  • Magnesium Oxide

Furthermore, certain medications should not be taken with alcohol or tobacco, which may also result in harmful interactions. Ask your doctor about the concurrent use of this drug along with alcohol or tobacco.

You should also inform your doctor about any other medical condition you may be suffering from., especially:

  • Depression
  • Mental illness
  • Kidney disease—It should be used with caution.

3 Proper Usage

To use Horizant properly, you must follow all instructions given by your doctor.

Gabapentin enacarbil also comes in an extended release form. You should swallow the extended release tablet as a whole. Avoid chewing, crushing and breaking the tablet. Try taking the dose with food.

If you are a patient with restless legs syndrome, avoid using this drug if you’re required to sleep during the day and remain awake at night.

To avoid adverse effects, this drug should be used exactly as prescribed by your doctor. Do not overuse or misuse this drug and do not use it longer than the recommended time. Read all the instructions mentioned in the medication guide.

Do not miss any dose. The dose of this drug varies according to the condition of each person. The number of doses per day, the time interval between the doses and the length of time you have to take the medicine depends on your condition individually and all these factors should only be determined by your healthcare provider. Follow each and every instruction of your doctor and also read the label carefully.

In case you miss one dose of this drug, take it as soon as you can. If it is almost time for your subsequent dose, you can then skip the missed dose and continue with your regular dosing schedule. Do not take two doses at once.


This medicine should be stored at room temperature within a closed container, away from heat, direct light and moisture. Keep this drug out of the reach of children. Do not store expired or outdated medicines or the medicine no longer needed. 

4 Precautions To Take

Before using Horizant, there are some precautions you must take.

Gabapentin may cause allergic reactions, vision changes, clumsiness, drowsiness, and behavior changes. Make sure to inform your doctor if you experience any of these symptoms.

Gabapentin should not be taken with alcohol. It adds to the effects of alcohol and other CNS depressants.

Also inform your doctor right away if you experience a rash, fever, swollen, painful, or tender lymph glands in the neck, axilla or groin, unusual bleeding or bruising, or yellowing eyes or skin. These may be symptoms of a serious and life-threatening allergic reaction.

Regular follow-up is necessary during and after the treatment. It is important to allow your doctor to monitor your progress and to make sure that there aren’t any side effects from the medication.

Contact your doctor if your symptoms have not improved even after taking the full course of treatment. The doctor may order some blood tests in order to determine the blood levels of the drug.

Avoid taking any other medicine unless thoroughly discussed with your doctor. Always ask your doctor before using any prescription, non-prescription or herbal medicine.

5 Potential Side Effects

As with many medications, there are several potential side effects associated with Horizant. Although these side effects may occur only in a handful of patients but if they do occur, contact your physician immediately.

This medication is associated with the following side effects:

  • Irritability
  • Discouragement
  • Feeling sad or empty
  • Lack of appetite
  • Loss of interest or pleasure
  • Rapid weight gain
  • Black, tarry stools
  • Tingling of the hands or feet
  • Tiredness
  • Trouble concentrating
  • Bloody or cloudy urine
  • Changes in behavior
  • Confusion
  • Chest pain or discomfort
  • Chills or fever
  • Difficulty with breathing
  • Dizziness or lightheadedness
  • Painful or difficult urination
  • Fainting
  • Fast heartbeat
  • Nausea or vomiting
  • Rash
  • Rapid, shallow breathing
  • Sore throat
  • Thoughts of killing oneself
  • Unusual bleeding or bruising
  • Swelling of the face, feet, or lower legs
  • Yellow eyes and skin
  • Upper right abdominal or stomach pain

Seek medical help instantly, if you experience any of these symptoms while on this medication. Also contact your healthcare professional immediately, if you have overdosed on this drug.

If any of these side effects becomes more bothersome or does not go away, contact your doctor.

6 Related Clinical Trials