TEGRETOL CR 400/MG PR TAB 30/TAB

Indications

Approved Uses

Epilepsy (focal/partial seizures and generalized tonic‑clonic seizures; mixed seizure patterns) and trigeminal neuralgia; bipolar disorder/mania is not an approved indication for Tegretol CR in many jurisdictions and should be treated as off‑label unless specifically stated in the local SFDA product label.

Off-Label Uses

Common off‑label uses include bipolar disorder (acute mania/maintenance where not locally approved), neuropathic pain syndromes (e.g., diabetic neuropathy, post‑herpetic neuralgia-evidence variable), alcohol withdrawal (adjunct), and restless legs syndrome (less common/variable evidence).

Dosage & Administration

Dosing by Condition

Epilepsy (adults, typical): start 200 mg twice daily (or lower such as 100-200 mg 1-2 times daily if sensitive), increase by ~200 mg/day at weekly intervals; usual maintenance 800-1200 mg/day in divided doses; max commonly 1600 mg/day. Trigeminal neuralgia: start 100 mg twice daily (or 200 mg/day), increase by 100-200 mg/day until pain control; usual maintenance 400-800 mg/day; max commonly 1200 mg/day.

Initial Dose

100-200mg once or twice daily, titrated gradually

Maintenance Dose

400-1200mg/day in 1-2 divided doses (prolonged-release formulation)

Maximum Dose

Typically not more than 1600 mg per day for adults; may be higher in some cases.

Children's Dosage

Children 6-12 years: Initial 100mg/day, increase by 100mg/week; Maintenance 400-800mg/day (20mg/kg/day). Children under 6 years: 10-20mg/kg/day in divided doses (immediate-release preferred). Prolonged-release tablets not recommended for children under 6 years

Dose Adjustment Notes

Start low and titrate gradually; avoid abrupt discontinuation; reassess dose after 2-4 weeks due to auto‑induction (reduced levels over time); use caution and consider lower doses in older adults and in hepatic impairment; no routine renal dose adjustment but monitor clinically and with levels.

How to Take

Oral prolonged‑release carbamazepine: swallow tablet whole; may be split only along the score line if a half‑dose is prescribed; do not crush or chew; take consistently with food (or after meals) to reduce GI upset; dose is typically given in 2 divided doses daily (some patients may be maintained once daily per local labeling/clinical judgment).

Side Effects

Common Side Effects

Common: dizziness, somnolence/drowsiness, ataxia, diplopia/blurred vision, nausea/vomiting, headache, fatigue; also clinically common/important: rash and hyponatremia (SIADH), and constipation/dry mouth can occur.

Side Effect Frequency

Very common (>10%): dizziness, somnolence/drowsiness, ataxia, nausea/vomiting, diplopia/blurred vision. Common (1-10%): headache, fatigue, dry mouth, constipation, rash, hyponatremia, leukopenia, elevated liver enzymes, weight gain/edema. Rare/very rare but serious: agranulocytosis/aplastic anemia/thrombocytopenia, severe cutaneous adverse reactions (SJS/TEN, DRESS), hepatitis/hepatic failure, SIADH, cardiac conduction abnormalities/arrhythmias.

Safety & Warnings

Contraindications

Contraindications: hypersensitivity to carbamazepine or tricyclic antidepressants; bone marrow depression; concomitant MAO inhibitor use (or within 14 days); atrioventricular (AV) block; concomitant use with delavirdine and with certain azole antifungals (e.g., voriconazole) due to major interaction/ineffectiveness.

Warnings & Precautions

Key precautions: screen at-risk ancestry for HLA-B*1502 before initiation (SJS/TEN risk); consider HLA-A*3101 where applicable; baseline/periodic CBC and LFTs; monitor sodium (hyponatremia/SIADH); monitor for suicidality; avoid abrupt withdrawal; assess for cardiac conduction disease (consider ECG if risk); counsel on major drug interactions and reduced hormonal contraceptive efficacy; note auto-induction may lower levels after 2-4 weeks requiring reassessment.

Age Restriction

No absolute minimum age for carbamazepine, but Tegretol CR/XR (prolonged/extended-release) tablets are generally not recommended for children <6 years; use immediate-release formulations for younger children when needed.

Driving Warning

May Cause Drowsiness

Drug Interactions

Drug Interactions

Carbamazepine is a strong enzyme inducer (CYP3A4/1A2/2C9/2C19, UGT) that lowers exposure to many drugs (e.g., oral contraceptives, warfarin, DOACs, many antidepressants/antipsychotics, immunosuppressants, methadone); its levels are increased by CYP3A4 inhibitors (macrolides like erythromycin/clarithromycin, azole antifungals, grapefruit juice) and decreased by inducers (e.g., rifampin); contraindicated with MAOIs and delavirdine, and avoid/contraindicated with voriconazole.

Interaction Severity

MAJOR/contraindicated: concomitant MAOIs (and within 14 days of stopping), strong CYP3A4 inhibitors that markedly raise levels (e.g., nefazodone; some azoles/macrolides depending on strength), and strong CYP3A4 inducers that can cause loss of efficacy; clinically major: oral hormonal contraceptives (reduced efficacy) and warfarin (reduced INR/anticoagulation) require active management. MODERATE-MAJOR: macrolides (erythromycin/clarithromycin), azole antifungals (ketoconazole/itraconazole/fluconazole), verapamil/diltiazem, and other antiseizure meds (phenytoin/valproate/lamotrigine) with bidirectional effects; lithium may increase neurotoxicity risk. MINOR: grapefruit is better treated as clinically significant (avoid) rather than minor.

Alcohol Interaction

Avoid

Special Populations

Pregnancy

Not assigned a pregnancy category; potential for congenital malformations and developmental disorders

Breastfeeding

Caution

Children

Children 6-12 years: Initial 100mg/day, increase by 100mg/week; Maintenance 400-800mg/day (20mg/kg/day). Children under 6 years: 10-20mg/kg/day in divided doses (immediate-release preferred). Prolonged-release tablets not recommended for children under 6 years

Elderly

Start at lower doses and titrate slowly; increased risk of hyponatremia, cardiac conduction disturbances, and CNS side effects; monitor serum sodium and ECG; standard adult maximum doses may not be appropriate

Kidney Impairment

No routine dose adjustment in renal impairment, but use caution and monitor (including sodium and drug levels) in severe renal dysfunction.

Liver Impairment

Use with caution in hepatic impairment; avoid/not recommended in severe hepatic impairment; monitor LFTs and clinical status closely and consider dose reduction based on tolerability/levels.

Storage & Patient Advice

Missed Dose

Take the missed dose as soon as remembered; if it is close to the next scheduled dose, skip the missed dose and resume the regular schedule; do not double doses.

Stopping the Medicine

Do not stop abruptly; taper gradually under medical supervision (typically over weeks, individualized; longer tapers may be needed depending on indication and seizure risk).

Overdose

Symptoms: CNS depression (drowsiness, ataxia, nystagmus, coma), seizures, anticholinergic effects, respiratory depression, and cardiac conduction abnormalities/arrhythmias; Management: emergency care with airway/ventilation support, ECG monitoring, activated charcoal (often multiple-dose), supportive care, and consider extracorporeal removal (e.g., hemodialysis/hemoperfusion) in severe poisoning.

Patient Counseling

Take exactly as prescribed; do not stop suddenly (risk of seizure recurrence). Swallow prolonged‑release tablets whole; may split only on the score if needed, but do not crush/chew (would destroy controlled release). Take with food if GI upset occurs. Avoid alcohol; use caution with driving/operating machinery until effects known (dizziness/drowsiness). Avoid grapefruit juice (can increase carbamazepine levels). Major interaction counseling: carbamazepine is a strong enzyme inducer and can reduce effectiveness of hormonal contraception-use reliable alternative/backup contraception; discuss pregnancy planning (teratogenic risk). Seek urgent care for rash/blistering, fever/sore throat/mouth ulcers, unusual bruising/bleeding, or jaundice (signals of serious cutaneous, hematologic, or hepatic reactions). Keep scheduled monitoring (CBC, LFTs, sodium, and drug levels as clinically indicated). Store below 30°C in original blister.

Monitoring Requirements

Baseline and periodic: CBC (including platelets), liver function tests, serum sodium/electrolytes; consider carbamazepine serum concentrations (typical therapeutic range ~4-12 mcg/mL) when adjusting dose, assessing adherence/toxicity, pregnancy, or interacting drugs; consider HLA‑B*1502 (and often HLA‑A*3101 where relevant) before initiation in at‑risk ethnic groups; consider ECG if cardiac disease/conduction risk; consider thyroid function with long‑term therapy.

Pharmacology

Mechanism of Action

Use‑dependent blockade of voltage‑gated sodium channels, stabilizing hyperexcited neuronal membranes and reducing repetitive firing and synaptic propagation.

Duration of Effect

Controlled/prolonged‑release carbamazepine provides approximately 12‑hour coverage per dose (typically dosed twice daily), with smoother plasma concentrations than immediate‑release; some patients may achieve 24‑hour control depending on regimen and response.

Half-Life

Single dose (before autoinduction): ~25-65 hours; after repeated dosing/autoinduction: ~12-17 hours.

Bioavailability

Oral bioavailability is high (approximately 70-85%); extended/prolonged‑release products mainly slow the rate of absorption without reducing the extent of absorption.

Metabolism

Extensive hepatic metabolism primarily via CYP3A4 to active metabolite carbamazepine-10,11-epoxide; also induces its own metabolism (auto-induction)

Protein Binding

Approximately 70-80% protein bound (mainly to albumin).

Product Information

Available Dosage Forms

For carbamazepine as an active substance: immediate‑release tablets, chewable tablets, oral suspension, and extended/prolonged‑release tablets (e.g., Tegretol CR/XR); extended‑release capsules are formulation/market dependent and not a standard Tegretol CR dosage form.

Composition per Dose

Each prolonged-release scored tablet: 400mg carbamazepine

Generic Availability

Yes

OTC Alternatives

No OTC alternative

Also Used For

Neuropathic Pain, Mood Stabilization, Trigeminal Neuralgia, Bipolar Disorder, Alcohol Withdrawal, Restless Legs Syndrome, Diabetic Peripheral Neuropathy, Post-herpetic Neuralgia

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