Lamotrigine XR

LAMICTAL XR

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What it isExtended-release antiepileptic modulating sodium, calcium, and HCN channels; adjunctive or monotherapy for seizures.

Why this oneIt is once daily for epilepsy; the bipolar-maintenance indication stays on IR.

What limits itRapid escalation or valproate coadministration raises serious-rash risk; stop promptly for a suspicious eruption.

FDA-approved for

seizures (adjunct/monotherapy) (2009)

FDA label

Read the full label on DailyMed ↗

BOXED WARNING Serious skin rashes (including Stevens-Johnson syndrome, toxic epidermal necrolysis) and/or rash-related death. Risk higher in pediatrics, with valproate coadministration, exceeding recommended initial dose or dose escalation, or with HLA-B*1502 allele. Discontinue at first sign of rash unless clearly not drug-related.

FDA dosing	Population	Start	Target	Max
Adjunctive therapy for primary generalized tonic-clonic and partial-onset seizures	Patients 13 yr and older	Depends on concomitant AED (e.g., 25 mg QOD with valproate; 25 mg QD if not on valproate/inducers; 50 mg QD with inducers)	200-600 mg QD depending on concomitant AEDs	600 mg QD
Conversion to monotherapy (partial-onset seizures, on a single AED)	Patients 13 yr and older	Per Table 1 escalation	250-300 mg QD	300 mg QD (monotherapy)

Titration Slow weekly titration per concomitant-AED-specific schedule; do not exceed recommended initial dose or escalation

Renal Reduced maintenance doses may be effective in significant renal impairment; use with caution in severe renal impairment

Hepatic No adjustment in mild; reduce initial/escalation/maintenance ~25% in moderate-severe without ascites and ~50% in severe with ascites

Instructions

Swallow tablets whole; do not chew, crush, or divide
May take with or without food, once daily
Discontinuation: taper over at least 2 weeks (~50% dose reduction per week)
Do not restart in patients who discontinued due to rash unless benefits outweigh risks
Adjust maintenance dose when starting/stopping estrogen-containing products

Contraindications

Hypersensitivity (e.g., rash, angioedema, acute urticaria, extensive pruritus, mucosal ulceration) to the drug or its ingredients

Cautions

Life-threatening serious rash / rash-related death
Hemophagocytic lymphohistiocytosis (HLH)
Multiorgan hypersensitivity (DRESS) and organ failure
Cardiac rhythm and conduction abnormalities (Class IB antiarrhythmic activity)
Blood dyscrasias
Suicidal behavior and ideation
Aseptic meningitis
Medication errors due to product name confusion
Withdrawal seizures with abrupt discontinuation

Adverse reactions

Dizziness
Tremor/intention tremor
Vomiting
Diplopia
Nausea
Somnolence

Pregnancy Registry data have not detected an increased frequency of major malformations overall; lamotrigine levels may fall during pregnancy requiring dose adjustment. NAAED pregnancy registry available.

Lactation Lamotrigine present in human milk; infants at risk of high serum levels - monitor for rash, apnea, drowsiness, poor sucking/weight gain.

⚠ BOXED WARNING