Genesis Banner
Fuel peak focus by day. Recharge your brain by night.

lamotrigine LAMICTAL

Class: AED/​Mood Stabilizer
FDA Indications: Bipolar Disorder, Epilepsy
Off-Label Use: Neuropathic Pain, Trigeminal Neuralgia, Cluster Headaches, Migraines, OCD, PTSD, Schizoaffective Disorder, Borderline Personality Disorder, Hallucinogen Persisting Perception Disorder, Depersonalization Disorder, Behavioral And Psychological Symptoms Of Dementia (BPSD), Delirium (with lorazepam)
Prescribing
Forms: 25, 100, 150, 200 mg tablet; 25, 50, 100, 200, 250, 300mg Tablet Extended Release 24 Hour; 25, 50, 100, 200mg ODT
Dose Range: 100-400 mg/day
Starting: Initial: Weeks 1 and 2: 25 mg qd; Weeks 3 and 4: 50 mg qd; Week 5: 100 mg qd; Week 6 and maintenance: 200 mg qd
Stopping: ↓ dose by ~50% per week, over at least 2 weeks unless safety concerns require a more rapid withdrawal.
Monitoring: Serum levels of concurrent anticonvulsants, LFTs, renal function

NAMI drug fact sheet

Precautions
Serious Side Effects: Stevens-Johnson syndrome (0.08-0.3%), aseptic meningitis, myoclonus after 2-3 years of treatment; lamotrigine is the third most common drug associated with DRESS; there have been 8 cases of Lamotrigine-Associated Hemophagocytic Lymphohistiocytosis since its FDA approval in 1994.
Side Effects: headache, sedation/somnolence, dizziness, diarrhea, nausea, vomiting, benign rash (10-11%)
Pharmacodynamics
1° MOA: Inhibits release of glutamate and inhibits voltage-sensitive Na+ channels, which stabilizes neuronal membranes; weak inhibitory effect on the 5HT3 receptor
Pharmacokinetics
t½: 25 (15-35)° TMAX: 1-3°
Substrate of: N-glucuronidation via UGT1A4; UGT1A1, UGT2B7
Inhibits: ∅ ; Induces: ∅
Active Metabolites: ∅
DDIs
  • - valproic acid inhibits lamotrigine glucuronidation, doubling its t½, so need to half lamotrigine dose
  • - carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, and atazanavir/ritonavir all induce lamotrigine glucuronidation
  • - birth control pills, because of their enzyme induction, can ↓ lamotrigine levels
Misc
  • - one of the best tolerated mood stabilzers with little weight gain or sedation
  • - if a patient discontinues for ≥5 half-lives, initial dosing titration must be restarted
  • - more effective in preventing depressive episodes than preventing mania, "a better floor than a ceiling," i.e. does not have good efficacy for acute bipolar mania
Special Populations

Category C—Fetal and/or placental concentrations similar to those in maternal plasma, generally considered by OBGYNs to be the mood stabilizer of choice during pregnancy

RID 9.2%; Limited Human Data—Potential Toxicity


Clearance is reduced by about a third in the elderly


There are no dosage adjustments required though t½ is longer in patients with renal failure

Moderate to severe impairment without ascites: ↓ initial, escalation, and maintenance doses by ~25%
Moderate to severe impairment with ascites: Decrease initial, escalation, and maintenance doses by ~50%

References
Lamictal Package Insert
Applied Clinical Pharmacokinetics And Pharmacodynamics Of Psychopharmacological Agents
Concise Guide To Drug Interaction Principles For Medical Practice
Foye's Principles Of Medicinal Chemistry
Successful Psychopharmacology: Evidence-Based Treatment Solutions For Achieving Remission

Print Page
logo

Developed & Designed by Kevin M. Nasky, D.O. • Built with Bootstrap, PHP & MySQL • Hosted by SiteGround
Last updated August 14 2025 21:35:12. Disclaimer: This website does not provide medical advice, nor is it a substitute for clinical judgment.