EpilepsyRx

Carbamazepine

Tegretol · Carbatrol · Equetro

Seizure aggravation / coverage
May aggravate absence or myoclonic seizures; review syndrome before use (NICE NG217, UK guidance).

DailyMed-verified antiseizure indications

Indication / use

Label / evidence summary
Tegretol: focal seizures with complex symptomatology, generalized tonic-clonic seizures, and mixed patterns containing these seizure types. Absence seizures are not controlled by this product.
Role
Maintenance
Class
Use- and voltage-dependent sodium-channel inhibition

Indications checked 26 September 2026. Product, route, age, and treatment-role limits apply. A DailyMed listing alone does not establish FDA approval.

Formulations & strengths

U.S. products unless another country is named. Strengths are per unit or stated volume.

Brand & formulation labels

Each link names the product and formulation it covers. Archived labels do not establish current availability.

Dosing & administration

Adult / product-specific schedule
Focal/generalized tonic-clonic seizures: start 200 mg twice daily; increase weekly. Typical 800–1,200 mg/day; maximum 1,600 mg/day in adults.
Pediatric
Age <6 years: start 10–20 mg/kg/day divided 2–4 times; usual maintenance 10–35 mg/kg/day. Ages 6–12 use fixed label increments and caps.
Titration / repeat dosing
Adults: start 200 mg twice daily; increase by up to 200 mg/day at weekly intervals to response, usually 800–1,200 mg/day. Children <6 years: 10–20 mg/kg/day divided, increasing weekly.

Practical administration

Product instructions
Tegretol tablets, XR tablets and suspension are taken with meals. Swallow XR tablets whole; do not crush or chew. Shake suspension. Converting tablets to suspension uses the same total daily dose in smaller, more frequent doses because peak concentrations differ.

Dose adjustment & concentrations

Renal impairment
No specific labeled adjustment; use clinical and concentration monitoring when organ dysfunction alters risk.
Hepatic impairment
Use caution and monitor; avoid in active liver disease when risk is unacceptable.
Serum reference information
4–12 mcg/mL total; interpret epoxide when clinically relevant

Safety

Boxed warning
Boxed warnings: serious dermatologic reactions (including SJS/TEN) and aplastic anemia/agranulocytosis. HLA-B*1502 testing is required before treatment in genetically at-risk populations.
Contraindications
Prior bone marrow depression; hypersensitivity to carbamazepine or related tricyclic compounds; MAO inhibitor use (allow ≥14 days after stopping); concomitant nefazodone.
Serious precautions & monitoring
Aplastic anemia/agranulocytosis and serious rash. Screen HLA-B*1502 in genetically at-risk ancestry before starting; assess HLA-A*3101 risk. Baseline CBC/liver function; sodium monitoring as appropriate. Tegretol suspension contains 25 mg/mL propylene glycol: patients younger than 5 years are at highest toxicity risk, and neonatal use requires careful benefit–risk assessment when no alternative is available. Count propylene glycol from all sources and monitor for hemolysis, hyperosmolar anion-gap acidosis, acute kidney injury and CNS toxicity.

Common / selected adverse effects

  • Dizziness
  • Drowsiness
  • Unsteadiness
  • Nausea
  • Vomiting
  • Blurred vision

Drug interactions: toxicity & clinical action

Partner / combinationClinical effectClinical action
CYP3A4 inhibitors (e.g., clarithromycin, azole antifungals) / grapefruitHigher carbamazepine exposure: diplopia, ataxia, somnolence and other toxicity.Choose alternatives when appropriate; monitor concentration and clinical toxicity when starting/stopping an inhibitor.
Valproate, brivaracetam or felbamateActive carbamazepine epoxide may rise despite a normal or falling carbamazepine level.Assess symptoms; consider epoxide levels and a carbamazepine reduction.
Lamotrigine, many other ASMs, hormonal contraceptives, anticoagulants and prednisoloneEnzyme induction lowers exposure; stopping carbamazepine can allow partner concentrations to rise.Plan dose/concentration follow-up when adding or removing carbamazepine; review contraceptive and anticoagulant choice.
MAO inhibitors / nefazodoneContraindicated combinations in the linked Tegretol label.Observe the label washout and avoid the combination.

Pregnancy & contraception

Fetal / neonatal risk
Carbamazepine exposure is associated with congenital malformations, including spina bifida; developmental disorders have also been reported.
Contraception
Enzyme induction can reduce hormonal contraceptive effectiveness; contraceptive failure and breakthrough bleeding have been reported. Use an effective alternative or backup method.

Clinical evidence

Research summaries describe studied populations and outcomes; they do not add indications or constitute treatment recommendations.

Extrapolation

Trial summary

Study design / duration
Approval predates modern Phase 3 conventions; controlled active-comparator epilepsy trials established efficacy. Contemporary labels summarize seizure-control evidence rather than one placebo-controlled pivotal design.
Primary endpoint
No single pivotal endpoint is identified in the cited source.
Results
Marketed before modern Phase 3 standards. Evidence comes from older active-comparator and controlled epilepsy trials establishing efficacy for focal and generalized tonic-clonic seizures; a single current-label placebo-adjusted Phase 3 percentage is not available.

Trial publications

Mechanism of action

  • Experimental evidence supports preferential binding to inactivated voltage-gated sodium channels, limiting sustained high-frequency firing and seizure propagation.
  • This is the principal mechanistic explanation, not a complete account of clinical efficacy. It is distinct from lacosamide’s label-described enhancement of slow inactivation.

Pharmacology

Adult values unless specified. Vd/F denotes apparent oral distribution volume.

Pharmacokinetics

Bioavailability
Oral absorption is substantial but formulation-dependent; the U.S. label does not give one absolute percentage. XR tablets have about 89% bioavailability relative to suspension.
Elimination half-life
25–65 hours initially; 12–17 hours after repeated dosing and autoinduction (U.S. label). Autoinduction develops over approximately 3–5 weeks.
Volume of distribution
Apparent distribution volume 0.8–1.9 L/kg, assuming complete absorption (UK SmPC).
Active metabolite(s)
Yes: carbamazepine-10,11-epoxide. It contributes pharmacologic effects and can contribute toxicity.
Active-metabolite half-life
Approximately 6 hours after a single oral dose of the epoxide itself (UK SmPC). Formation, enzyme induction and interacting drugs can alter its disposition during carbamazepine treatment.
Protein binding
~76%
Metabolism / elimination
CYP3A4; strong autoinduction and broad enzyme induction

The initial-dose half-life is substantially longer; an unchanged dose does not imply unchanged exposure during autoinduction.

Molecular structure

Molecular structure of Carbamazepine
Principal compound; salt and product forms may differ.
NIH PubChem structure and record ↗

Product history

Initial U.S. approval
1968
Market / formulation history
1968 in the U.S.
Brands
Tegretol · Carbatrol · Equetro
Manufacturer / marketer
Novartis (Tegretol); Validus (Carbatrol/Equetro)
Generic availability
Yes
Related drugs
Parent dibenzazepine relative of oxcarbazepine and eslicarbazepine acetate.

Sources & review status

Representative sources are selected product labels, not an exhaustive list of generic manufacturers. Consult the exact product and formulation prescribed. Brand-name package inserts are linked separately.

Brand references: Tegretol / Tegretol XR ↗ · Carbatrol ↗ · Equetro ↗

Indications and DailyMed PDFs checked: 2026-09-26. Other profile sources reviewed: 2026-09-15 · label revision noted at that review: July 2026 T2026-28. This is a draft reference; final review is pending.

Send a comment · Privacy & traffic measurement