What is Horizant? Uses, warnings & side effects

Updated May 14, 2025  •  Published Dec 30, 2020

Horizant overview

BRAND NAMES:

  • Horizant

Generic Names:

  • Horizant

Uses:

  • Treats restless leg syndrome (RLS) and pain caused by shingles.

Therapeutic Classes:

  • Analgesic

Forms:

  • Long Acting Tablet

How it’s taken:

  • By mouth

What is Horizant used for?

What form(s) does Horizant come in?

  • Long Acting Tablet

What are common Horizant dosages?

  • Tablet 300mg

  • Tablet 600mg

Horizant images - What does Horizant look like?

  • Horizant
    300mg tablet extended release

  • Horizant
    600mg tablet extended release

How to take Horizant

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.

  • Oral routeIt is best to take this medicine with food or milk.

  • Swallow the extended-release tablet whole. Do not crush, break, or chew it.

  • This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.

  • Missed dose: If you miss a dose, skip that dose and go back to your regular dosing schedule.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

  • This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.

  • Missed dose: If you miss a dose, skip that dose and go back to your regular dosing schedule.

  • Oral routeIt is best to take this medicine with food or milk.

  • Swallow the extended-release tablet whole. Do not crush, break, or chew it.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

What to do if you miss a dose of Horizant

Horizant contraindications - Who shouldn't take Horizant?

  • This medicine is not right for everyone. Do not use it if you had an allergic reaction to gabapentin enacarbil.

Horizant warnings

  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

  • Tell your doctor if you are pregnant or breastfeeding, or if you have kidney problems (including patients receiving dialysis), or a history of depression or mental health problems. Tell your doctor if you need to sleep during daytime and remain awake at night.

  • This medicine may cause the following problems: Changes in mood or behavior, including suicidal thoughts or behaviorRespiratory depression (serious breathing problem that can be life-threatening), when used with narcotic pain medicinesDrug reaction with eosinophilia and systemic symptoms (DRESS) or multiorgan hypersensitivity, which may damage the liver, kidney, blood, heart, or muscles

  • Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.

  • This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Horizant interactions & what to avoid when taking Horizant

  • Some medicines can affect how gabapentin enacarbil works. Tell your doctor if you are also using other medicines that contain gabapentin.

  • Do not drink alcohol while you are using this medicine.

  • Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol. Tell your doctor if you are also using lorazepam, morphine, oxycodone, or zolpidem.

  • Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.

  • This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Horizant side effects - How does Horizant make you feel?

Serious Side Effects

  • Sudden mood changes, unusual moods or behavior, including extreme happiness or depression, thoughts or attempts of killing oneself

  • Unusual bleeding, bruising, or weakness

  • Fever, rash, swollen or tender glands in the neck, armpit, or groin

  • Yellow eyes or skin

  • Rapid weight gain, swelling in your hands, ankles, or feet

  • Blue lips, fingernails, or skin, trouble breathing, chest pain

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing

Less Serious Side Effects

  • Dizziness, drowsiness, sleepiness, tiredness

  • Headache

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