TaperCommunitylamotrigine
Boxed Warning
Serious skin rashes including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), especially during initial titration. Increased risk of suicidal thoughts and behavior (anticonvulsant class warning).
Lamotrigine is an anticonvulsant approved for epilepsy (partial seizures, primary generalized tonic-clonic seizures, Lennox-Gastaut syndrome) and maintenance treatment of bipolar I disorder. It is the only mood stabilizer with strong evidence for preventing bipolar depression.
25mg, 50mg, 100mg, 200mg
Tablets: 25mg, 100mg, 150mg, 200mg; Chewable/dispersible tablets: 2mg, 5mg, 25mg; Orally disintegrating tablets (ODT): 25mg, 50mg, 100mg, 200mg; Extended-release tablets (XR): 25mg, 50mg, 100mg, 200mg, 250mg, 300mg
Category C (risk cannot be ruled out)
Blocks voltage-sensitive sodium channels, stabilizing neuronal membranes and inhibiting release of excitatory neurotransmitters (primarily glutamate). May also modulate calcium channels and HCN channels. The anti-glutamate mechanism is thought to underlie its mood-stabilizing effects.
Used as mood stabilizer. Must taper slowly — if stopped and restarted, must re-titrate from scratch due to SJS risk. Available in chewable/dispersible tablets.
Gradual taper essential. If a dose is missed for >5 days, re-titration from low dose is required due to serious rash risk (SJS). Chewable tablets allow fine dose adjustments.
Toxicity
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) — risk highest with rapid titration, concurrent valproate, and in children. Aseptic meningitis. Multiorgan hypersensitivity (DRESS). Suicidal ideation (anticonvulsant class warning).
Pharmacokinetics
Rapidly and completely absorbed after oral administration. Bioavailability ~98%. Tmax ~1.4–4.8 hours. Food does not affect absorption.
~0.9–1.3 L/kg
Hepatic via UGT glucuronidation (primarily UGT1A4). Does not undergo significant CYP metabolism. Valproate inhibits lamotrigine glucuronidation (doubles half-life); enzyme inducers (carbamazepine, phenytoin) accelerate metabolism.
Renal (~94%, with ~10% as unchanged lamotrigine and ~76% as 2-N-glucuronide conjugate). Fecal (~2%).
~55%
~30 mL/min (apparent clearance; varies significantly with co-medications)
Browse our map of deprescribing-informed providers worldwide.