What is HORIZANT used for?

HORIZANT is used to treat moderate-to-severe primary Restless Legs Syndrome (RLS) and to manage postherpetic neuralgia (PHN) in adults.

Can I crush or chew HORIZANT tablets?

No, you should swallow HORIZANT tablets whole and do not cut, crush, or chew them.

Can I take HORIZANT with food?

Yes, you should take HORIZANT with food.

Is HORIZANT the same as regular gabapentin?

No, HORIZANT is not substitutable with other gabapentin products because they have different profiles in the body.

What should I do if I miss a dose of HORIZANT?

For RLS, wait until the next day to take your dose. For PHN, skip the missed dose and take the next one at your regular time.

Can HORIZANT affect my ability to drive?

Yes, HORIZANT may cause significant driving impairment, so do not drive until you know how it affects you.

Can I stop taking HORIZANT suddenly?

No, stopping HORIZANT abruptly may increase your risk of seizures or cause withdrawal symptoms.

What are the common side effects of HORIZANT?

Common side effects include dizziness, sleepiness, and headache.

Can I drink alcohol while taking HORIZANT?

It is not recommended to consume alcohol while taking HORIZANT because it can cause the drug to release faster.

Is HORIZANT safe to use during pregnancy?

There is no adequate data on the risks of using HORIZANT in pregnant women.

Gabapentin Enacarbil | CAS 478296-72-9 | TZDUHAJSIBHXDL

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Calcium channel modulator

HORIZANT (gabapentin enacarbil) is a prescription medicine used to treat moderate-to-severe Restless Legs Syndrome (RLS) in adults and to manage postherpetic neuralgia (PHN) in adults. It is an extended-release tablet that works as a prodrug for gabapentin. Because it is an extended-release formula, it cannot be swapped for other gabapentin products. Common side effects include dizziness and sleepiness.

How it worksHORIZANT is a prodrug that turns into gabapentin in the body. It works by modulating voltage-gated calcium channels, which helps manage nerve-related pain and restless leg symptoms.

Brand names:HORIZANT

Used for

Moderate-to-severe primary Restless Legs Syndrome (RLS) in adultsManagement of postherpetic neuralgia (PHN) in adults

Conditions

Restless Legs SyndromePostherpetic neuralgia

Class

Calcium channel modulatorAnticonvulsantNervous system

How to take

FormsExtended-release tablet

RoutesOral

For RLS, the usual dose is 600 mg once daily around 5 PM. For PHN, the starting dose is 600 mg in the morning for 3 days, then increasing to 600 mg twice daily. Always swallow tablets whole; do not crush, chew, or cut them. Take with food.

Do not substitute HORIZANT with other gabapentin products because they work differently in your body. If you have kidney issues, your dose may need to be adjusted.

Missed dose: If you miss a dose for RLS, take the next one the following day. For PHN, skip the dose and take the next one at your regular scheduled time.

Key warnings

·Do not drive until you know how HORIZANT affects you, as it may cause significant impairment.
·Stopping this medicine suddenly can increase the risk of seizures or cause withdrawal symptoms.
·Monitor for any new suicidal thoughts or behaviors.
·Using this with other drugs that slow down the central nervous system may cause dangerous breathing problems.
·Alcohol can cause the medicine to release too quickly into your body; avoid alcohol while taking it.

Do not use if

·None listed

Side effects

Common

DizzinessSleepiness (somnolence/sedation)Headache

Serious

·Suicidal thoughts or behaviors
·Seizures (if stopped suddenly)
·Breathing problems (respiratory depression)
·Severe allergic reactions (DRESS/multiorgan hypersensitivity)
·Impaired driving ability

Seek help if

·Suicidal thoughts
·Difficulty breathing
·Severe allergic reaction

Interactions

·Alcohol (can make the drug release faster)
·Morphine (can increase sleepiness, dizziness, and nausea)
·Gralise
·Lyrica

FoodTake HORIZANT with food.

AlcoholDrinking alcohol is not recommended because it can cause the drug to release faster than intended.

Special populations

PregnancyThere is not enough data on the risks of using HORIZANT during pregnancy. In animal studies, it caused developmental issues. Using it with opioids near delivery might increase the risk of newborn withdrawal.

PediatricThe safety and effectiveness of HORIZANT in children have not been studied.

GeriatricClinical trials for RLS did not include enough people aged 65 and older to know if they respond differently than younger adults. However, many people in the PHN trials were 65 or older.

Talk to your doctor

Monitor

·Suicidal thoughts or behaviors
·Breathing patterns
·Driving ability
·Seizure activity

Questions to ask

·How should I adjust my dose if I have kidney problems?
·Is it safe to take this with my other medications?
·What should I do if I feel suicidal or have unusual thoughts?
·How long should I wait before driving after taking a dose?

Pharmacokinetics

BioavailabilityProvides approximately dose-proportional and extended exposure to gabapentin.

MetabolismIs a prodrug of gabapentin; absorption involves active transport via MCT-1.

Practical

OverdoseTaking too much can cause increased dizziness and sleepiness. Symptoms of an overdose may include double vision, tremors, slurred speech, drowsiness, altered mental state, and diarrhea. Fatal breathing problems have occurred with overdose.

StorageStore at 25°C (77°F). Keep away from moisture and do not remove desiccants.

Ingredients

Inactive

colloidal silicon dioxidedibasic calcium phosphate dihydrateglyceryl behenatemagnesium stearatesodium lauryl sulfatetalc

Educational summary derived from FDA labeling, AI-assisted. Not medical advice — consult a healthcare professional. Updated 2026-04-25.