Carbamazepine

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Drugs Dictionary: Carbamazepine

Carbamazepine

Trade Name

Tegretol, Tegretol XR, Carbatrol (extended-release); generic carbamazepine

Classification

Anticonvulsant; mood stabilizer; sodium channel blocker

Dosage/Route

* Dosage:
- – Immediate-release (IR) tablets: 100 mg, 200 mg
- – Extended-release (XR): 100 mg, 200 mg, 400 mg
- – Suspension: 100 mg/5 mL
* Route: Oral (PO)

Usual Dosage

* Seizures (Adults): Start 200 mg PO BID (IR) or once daily (XR); increase by 200 mg/day weekly; usual 800-1200 mg/day; max 1600 mg/day
* Bipolar Disorder: Start 200 mg PO BID; usual 400-1600 mg/day
* Trigeminal Neuralgia: Start 100 mg PO BID; usual 400-800 mg/day; max 1200 mg/day
* Children (≥6): 10-20 mg/kg/day, divided BID-QID; titrate to max 35 mg/kg/day
* Split doses to reduce side effects

Mechanism of Action

Blocks voltage-gated sodium channels in neuronal membranes, stabilizing hyperexcitable neurons. Reduces seizure propagation, stabilizes mood (bipolar), and dampens nerve pain signals (neuralgia)

Side Effects & Adverse Effects

* Side Effects: Dizziness, drowsiness, nausea, blurred vision.
* Adverse Effects:
- – Bone marrow suppression (boxed warning; agranulocytosis, aplastic anemia).
- – Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) (boxed warning; esp. HLA-B*1502 Asians).
- – Hyponatremia (SIADH-like effect).
- – Hepatotoxicity, teratogenicity (fetal harm)

Nursing Management (Implications & Teachings)

* Implications:
- – Monitor CBC, LFTs, sodium baseline/periodically (hematologic/hepatic risk)
- – Assess for rash (SJS/TEN—stop if severe); neuro status (dizziness)
- – XR: Don’t crush/chew; suspension: Shake well, don’t mix with other liquids
- – Screen for HLA-B*1502 in Asians (SJS risk)
* Teachings:
- – Take with food to reduce GI upset
- – Report fever, bruising, rash, or yellowing
- – Avoid alcohol, driving if drowsy
- – Don’t stop abruptly (seizure risk); use contraception (teratogenic)