What Is Oxtellar XR? Uses, Dosage, and What You Need to Know in 2026

Oxtellar XR is a prescription extended-release anticonvulsant medication used to treat partial-onset seizures (also called focal seizures). It's made by Supernus Pharmaceuticals and contains oxcarbazepine as its active ingredient in an extended-release formulation designed for once-daily dosing. Here's everything you need to know about Oxtellar XR in 2026.

What Is Oxtellar XR Used For?

Oxtellar XR is FDA-approved as adjunctive (add-on) therapy for partial-onset seizures in:

• Adults (18 years and older)
• Children aged 6 to 17 years

Partial-onset seizures (also called focal aware seizures and focal impaired awareness seizures) begin in one specific area of the brain rather than involving the whole brain simultaneously. They account for approximately 60% of all epilepsy cases. Oxtellar XR helps prevent these seizures from starting or spreading by stabilizing overactive electrical activity in the brain.

Oxtellar XR is used alongside (not instead of) other antiepileptic drugs in most cases. Your neurologist may prescribe it as part of a multi-drug regimen if a single medication hasn't provided complete seizure control.

How Does Oxtellar XR Work?

After you take Oxtellar XR, it's converted in your body to its active form: 10-monohydroxyderivative (MHD). MHD works primarily by blocking voltage-sensitive sodium channels in nerve cells. When sodium channels are blocked, overexcited neurons can't fire as rapidly, which helps prevent seizures from starting and spreading. The medication also increases potassium conductance and modulates calcium channels, providing additional stabilizing effects.

Oxtellar XR vs. Trileptal: What's the Difference?

Both contain oxcarbazepine, but they differ in important ways:

• Dosing frequency: Oxtellar XR is once daily; Trileptal is twice daily
• Food restrictions: Oxtellar XR must be taken on an empty stomach (1 hour before or 2 hours after food); Trileptal can be taken with or without food
• Peak blood levels: Oxtellar XR produces lower peak MHD concentrations, which may reduce some side effects like dizziness and diplopia
• Age range: Oxtellar XR is for ages 6+; Trileptal is for ages 2+
• Dose equivalence: Higher doses of Oxtellar XR may be needed compared to Trileptal IR due to different bioavailability profiles

Oxtellar XR Dosage

Oxtellar XR comes in three tablet strengths: 150 mg, 300 mg, and 600 mg. Dosing guidelines:

• Adults: Start at 600 mg once daily; increase by 600 mg/week as tolerated; target dose 1,200–2,400 mg once daily
• Children (6-17 years): Weight-based dosing; start at 12-15 mg/kg/day once daily (maximum 900 mg in week 1)
• Renal impairment: Lower starting dose recommended; use immediate-release formulation for ESRD

Tablets must be swallowed whole — do not crush, chew, or split them. Take on an empty stomach at the same time each day.

Important Warnings and Contraindications

• Do not use if allergic to oxcarbazepine or eslicarbazepine acetate
• Carbamazepine allergy: Cross-hypersensitivity is common — tell your doctor if you've had reactions to Tegretol
• Birth control: Oxtellar XR can make hormonal contraceptives less effective — use additional birth control methods
• Pregnancy: May harm the unborn baby — tell your doctor immediately if you become pregnant
• Never stop abruptly: Sudden discontinuation can cause increased seizures or status epilepticus

Is Oxtellar XR a Controlled Substance?

No. Oxtellar XR is not a DEA-scheduled controlled substance. It does not have abuse potential, and there are no DEA restrictions on prescribing or refilling. This means it can be prescribed via telehealth, refilled by any licensed prescriber, and does not require special prescription forms in most states.

Finding Oxtellar XR at a Pharmacy

Oxtellar XR is a specialty brand-name medication that isn't stocked at every retail pharmacy. If you're having trouble finding it, medfinder can help by calling pharmacies near you to find which ones have it in stock. For more details on why it can be hard to find, see our availability guide.