Oxcarb XR300 mg

Oxcarb XR is an anticonvulsant (antiepileptic) medicine indicated for the treatment of partial-onset (focal) seizures.

Established / FDA-approved uses

• Monotherapy in the treatment of partial seizures in adults and in children 4 years of age and older.
• Adjunctive therapy (used together with other antiepileptic drugs) in the treatment of partial seizures in adults and in children 4 years of age and older.

Off-label / less-established uses

• Oxcarb XR is sometimes used off-label for neuropathic pain (e.g. trigeminal neuralgia) and for mood stabilization in bipolar disorder, although it is not FDA-approved for these uses and evidence is more limited than for approved anticonvulsants used for these indications.

Use of Oxcarb XR for any indication should be guided and monitored by a physician.

Each tablet/oral suspension of Oxcarbazepine contains Oxcarbazepine as the active ingredient. Oxcarbazepine is commonly available as film-coated tablets (e.g. 150 mg, 300 mg, 600 mg) and as an oral suspension (e.g. 300 mg/5 mL) for patients who cannot swallow tablets.

Oxcarb XR is an anticonvulsant medicine chemically related to carbamazepine (it is the keto analog/derivative of carbamazepine).It is used to control partial-onset seizures in people with epilepsy, either alone or together with other antiepileptic medicines.

Oxcarb XR works by stabilizing over-excited nerve membranes in the brain, which reduces the abnormal electrical activity that causes seizures.It is largely converted in the body to an active metabolite (the 10-monohydroxy derivative, MHD) that is responsible for most of its effect.

Anticonvulsant / Antiepileptic drug (AED) - carboxamide/keto derivative related to carbamazepine. Oxcarb XR is classified as a voltage-gated sodium channel blocker.

Oxcarbazepine is a keto analog of carbamazepine. Its principal mechanism of action is thought to be blockade of voltage-sensitive sodium channels,which stabilizes hyperexcited neuronal membranes, inhibits repetitive neuronal firing, and reduces propagation of synaptic impulses.Oxcarbazepine and its main active metabolite (10-monohydroxy derivative, MHD) may also affect potassium conductance and modulate high-voltage activated calcium channels.

Pharmacokinetics: Oxcarbazepine is rapidly and almost completely absorbed after oral administration and is extensively metabolized by the liver(primarily by cytosolic enzymes, not the CYP450 system to a major extent) to its active metabolite, MHD, which is responsible for most of the pharmacological activity.MHD is further metabolized and excreted mainly by the kidneys. The elimination half-life of MHD is approximately 9 hours.

Oxcarb XR tablets should be swallowed whole with a sufficient amount of liquid; they may be taken with or without food.Oxcarb XR oral suspension should be shaken well before use and can be measured using an oral dosing syringe, taken directly or mixed in a small glass of water immediately before swallowing;it may also be taken with or without food. Tablets and oral suspension of Oxcarb XR may be interchanged at equal total daily doses.Do not change from tablets to suspension or vice versa without consulting the prescribing physician. Always take Oxcarb XR exactly as prescribed, at the same times each day.

Oxcarb XR has the following clinically significant drug interactions:

• Hormonal contraceptives: Oxcarb XR induces certain liver enzymes and can reduce the plasma levels and effectiveness of oral/hormonal contraceptives (e.g. ethinyl estradiol, levonorgestrel). Women of childbearing potential should use an alternative or additional non-hormonal method of contraception while taking Oxcarb XR.
• Phenytoin: Oxcarb XR can increase phenytoin plasma levels at higher Oxcarb XR doses (≥1200 mg/day), and phenytoin dose reduction may be needed.
• CYP3A4/CYP3A5 substrates: Oxcarb XR induces CYP3A4/3A5 and may reduce plasma levels of drugs metabolized by these enzymes (e.g. some calcium channel blockers, cyclosporine); doses of such drugs may need adjustment.
• Other drugs causing hyponatremia: Concurrent use of Oxcarb XR with diuretics, SSRIs, or other drugs that lower serum sodium can increase the risk of clinically significant hyponatremia (see Precautions and Warnings).
• CNS depressants and alcohol: Concurrent use with other central nervous system depressants (e.g. sedatives, opioids, alcohol) may increase somnolence and dizziness caused by Oxcarb XR.
• Other anticonvulsants: Interactions with other antiepileptic drugs (e.g. carbamazepine, phenobarbital, valproic acid, lamotrigine) can be variable and may require dose adjustment; enzyme-inducing antiepileptics may lower MHD (active metabolite of Oxcarb XR) levels.

Always inform the physician about all other medicines being taken before starting Oxcarb XR.

Common side effects of Oxcarb XR include:

• Dizziness and somnolence (sleepiness)
• Diplopia (double vision) and other visual disturbances
• Ataxia (unsteady gait/coordination problems)
• Headache and fatigue
• Nausea and vomiting
• Abnormal gait, tremor, nystagmus
• Rash

Hyponatremia (low blood sodium) is a notable and relatively common side effect of Oxcarb XR, more so than with many other anticonvulsants; it can occasionally be severe (see Precautions and Warnings).

Serious but less common side effects that require prompt medical attention include serious skin reactions (see Precautions and Warnings), multi-organ hypersensitivity reactions, and mood/behavioral changes including suicidal thoughts.

Oxcarb XR should be used during pregnancy only if clearly needed and if the potential benefit to the mother justifies the potential risk to the fetus; this decision should always be made in consultation with a physician.

Like other antiepileptic drugs, Oxcarb XR has been associated with an increased risk of congenital malformations when taken during pregnancy, although data suggest the risk profile may differ from some other anticonvulsants. Physicians may recommend folic acid supplementation before and during pregnancy in women taking Oxcarb XR. Antiepileptic therapy should generally not be stopped abruptly during pregnancy without medical advice, because uncontrolled seizures also carry risk to mother and fetus.

Oxcarb XR and its active metabolite pass into breast milk. Breastfeeding while taking Oxcarb XR should only be done after discussing the potential risks and benefits with a physician, with the infant monitored for drowsiness or poor feeding.

Hyponatremia

Oxcarb XR can cause clinically significant hyponatremia (serum sodium below 125 mmol/L in some cases). This risk is higher during the first few months of treatment, but can occur at any time. Serum sodium should be monitored in patients at higher risk (e.g. those on other medicines that lower sodium, or with kidney disease) and in anyone who develops symptoms such as nausea, headache, confusion, or worsening seizures while on Oxcarb XR.

Serious skin reactions

Oxcarb XR can rarely cause serious dermatologic reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Patients with the HLA-B*1502 allele (more common in certain Asian ancestries) who have a history of hypersensitivity to carbamazepine may be at increased risk given the structural similarity between the two drugs; genetic testing may be considered by the physician in at-risk patients before starting Oxcarb XR. Any new rash, blistering, mouth sores, or skin peeling while taking Oxcarb XR requires immediate medical evaluation and, typically, discontinuation of the drug.

Multi-organ hypersensitivity reactions

Oxcarb XR has been associated with rare but serious multi-organ hypersensitivity reactions (including fever, rash, and involvement of organs such as the liver, kidneys, or blood) - sometimes called anticonvulsant hypersensitivity syndrome or DRESS. Treatment must be stopped immediately if such a reaction is suspected.

Other precautions

• Do not stop Oxcarb XR abruptly, as this can precipitate increased seizure frequency or status epilepticus; discontinuation should be tapered gradually under medical supervision.
• Use with caution in patients with cardiac conduction abnormalities (e.g. AV block), as Oxcarb XR may rarely cause cardiac arrhythmia.
• Like other antiepileptic drugs, Oxcarb XR may be associated with a small increased risk of suicidal thoughts or behavior; patients and caregivers should watch for mood changes, depression, or unusual behavior and report these promptly.
• May cause dizziness and somnolence; caution is advised when driving or operating machinery until the effect of Oxcarb XR on the individual is known.
• Use with caution in patients with hepatic or renal impairment (dose adjustment may be needed).

Overdose of Oxcarb XR may cause somnolence, dizziness, nausea, vomiting, ataxia, and, in severe cases, coma, hyponatremia, cardiac conduction abnormalities, or respiratory depression.

If an overdose of Oxcarb XR is suspected, seek immediate medical attention or contact emergency services / a poison control center right away. Do not attempt to treat an overdose at home. Management in a hospital setting is generally supportive (there is no specific antidote), and may include monitoring of vital signs, cardiac monitoring, correction of electrolyte disturbances, and general supportive care.

Store at room temperature (below 30°C), protected from light and moisture. Keep out of reach of children.

Renal impairment

In patients with creatinine clearance below 30 mL/min, Oxcarb XR therapy should be initiated at half the usual starting dose with slower titration (see Dosage and Administration).

Hepatic impairment

No dose adjustment is generally needed in mild-to-moderate hepatic impairment; Oxcarb XR has not been extensively studied in severe hepatic impairment, so caution and close monitoring are advised.

Elderly

Elderly patients may be more susceptible to hyponatremia and dizziness/somnolence with Oxcarb XR; dose adjustment may be guided by renal function and clinical response.

Children

See Pediatric Uses for age-specific information; safety and efficacy of Oxcarb XR have not been established in children below 4 years of age.

The duration of treatment with Oxcarb XR is individualized by the treating physician based on seizure control, response, and tolerability, and is typically long-term for chronic management of epilepsy.Oxcarb XR should not be stopped or the dose changed without medical advice, and any discontinuation should be done gradually (tapered) to reduce the risk of rebound seizures.

Anticonvulsants (antiepileptic drugs); Oxcarbazepine belongs to the carboxamide/keto-derivative class, structurally related to carbamazepine.

Oxcarbazepine and its active metabolite (MHD) primarily block voltage-gated sodium channels in neurons, stabilizing hyperexcitable nerve cell membranes,inhibiting repetitive neuronal firing, and reducing the spread of abnormal electrical impulses that cause seizures.It may also modulate calcium and potassium channel activity, contributing to its anticonvulsant effect. See Pharmacology for full detail.

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Oxcarb XR is approved for use, as monotherapy or adjunctive therapy for partial seizures, in children 4 years of age and older, using weight-based dosing that is individualized and titrated by the treating physician.

Safety and efficacy of Oxcarb XR have not been established in children younger than 4 years of age.

Children and adolescents taking Oxcarb XR should be monitored for the same risks seen in adults, including hyponatremia, serious skin reactions, and mood/behavioral changes, as well as for growth and cognitive development during long-term therapy.