II. Indications
III. Mechanism
- Phenyltriazine anticonvulsant
IV. Pharmacokinetics
- Oral bioavailability: 98%
- Elimination half-life: 22 to 36 hours
V. Adverse Effects: Dose related
- Dizziness
- Incoordination
- Tremor
- Ataxia
- Diplopia
- Headache
- Insomnia
- Somnolence
- Blurred vision
- Nausea or Vomiting
VI. Adverse Effects: Other
- Serious skin rash (Incidence 0.08% in adults)
- Aplastic Anemia
- Thrombocytopenia
- Neutropenia
- Pancytopenia
- Aseptic Meningitis
- Serotonin Syndrome
VII. Drug Interactions
- Valproic Acid
- Carbamazepine
- Phenytoin
- Phenobarbital
- Primidone
- Rifampin
- Oral Contraceptives
VIII. Dosing: Adults
- Initial: 25 mg every other day for 2 weeks
- Next: 25 mg orally daily for 2 weeks
- Target dose: 50-100 mg orally twice daily
- Maximum dose: 400 mg/day
- Precautions
- Slow titration over 6 weeks or more reduces the risk of Stevens-Johnson Syndrome
- Dosing adjustments are needed when used with agents listed under Drug Interactions
IX. Monitoring
- Obtain labs monthly for the first 2 months and then every 3 to 12 months
- Complete Blood Count
- Liver Function Test
X. Approach: Toxicity or Overdose
- Evaluate as Unknown Ingestion
- Obtain other toxicologic screening including Acetaminophen level, Serum Glucose
- Electrocardiogram
- Effects in Overdose
- Ventricular Dysrhythmia
- Lamictal inhibits voltage-gated Sodium channels
- Wide QRS Complex
- Treat with Sodium Bicarbonate ampules until QRS Complex narrows
- Serotonin Syndrome
- Lamictal inhibits Serotonin reuptake
- Neurologic Effects
- Sedation (most common finding in Overdose)
- Seizures
- Paradoxical (as Lamictal is foremost an anticonvulsant)
- Children may experience Seizures at doses >30 mg/kg
- Agitation
- Increased Deep Tendon Reflexes (hyperreflexia)
- Myoclonic Jerks
- Miscellaneous
- Ventricular Dysrhythmia
- Management
- Activated Charcoal
- Consider if <1 hour from time of ingestion, and patient without aspiration risk
- QRS Widening
- See above (regarding bicarbonate)
- Seizures
- See Status Epilepticus
- Benzodiazepines
- Consider Propofol and intubation
- Consider Hemodialysis
- Activated Charcoal
- Disposition
- If asymptomatic at 4-6 hours after ingestion, may discharge home
- References
- Tomaszewski (2020) Crit Dec Emerg Med 34(1): 28
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| lamotrigine (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| LAMOTRIGINE 100 MG TABLET | Generic | $0.06 each |
| LAMOTRIGINE 150 MG TABLET | Generic | $0.08 each |
| LAMOTRIGINE 200 MG TABLET | Generic | $0.08 each |
| LAMOTRIGINE 25 MG DISPER TAB | Generic | $0.23 each |
| LAMOTRIGINE 25 MG TABLET | Generic | $0.06 each |
| LAMOTRIGINE 5 MG DISPER TABLET | Generic | $0.20 each |
| LAMOTRIGINE ER 100 MG TABLET | Generic | $5.40 each |
| LAMOTRIGINE ER 200 MG TABLET | Generic | $4.92 each |
| LAMOTRIGINE ER 25 MG TABLET | Generic | $2.42 each |
| LAMOTRIGINE ER 250 MG TABLET | Generic | $12.02 each |
| LAMOTRIGINE ER 300 MG TABLET | Generic | $8.44 each |
| LAMOTRIGINE ER 50 MG TABLET | Generic | $5.63 each |
| LAMOTRIGINE ODT 100 MG TABLET | Generic | $7.18 each |
| LAMOTRIGINE ODT 200 MG TABLET | Generic | $8.21 each |
| LAMOTRIGINE ODT 25 MG TABLET | Generic | $5.35 each |
| LAMOTRIGINE ODT 50 MG TABLET | Generic | $6.06 each |
| lamictal (on 4/24/2017 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| LAMICTAL 100 MG TABLET | Generic | $0.06 each |
| LAMICTAL 150 MG TABLET | Generic | $0.08 each |
| LAMICTAL 200 MG TABLET | Generic | $0.08 each |
| LAMICTAL 25 MG TABLET | Generic | $0.06 each |
| LAMICTAL ODT 100 MG TABLET | Generic | $7.18 each |
| LAMICTAL ODT 200 MG TABLET | Generic | $8.21 each |
| LAMICTAL ODT 50 MG TABLET | Generic | $6.06 each |
| LAMICTAL XR 100 MG TABLET | Generic | $5.40 each |
| LAMICTAL XR 200 MG TABLET | Generic | $4.92 each |
| LAMICTAL XR 300 MG TABLET | Generic | $8.44 each |
| LAMICTAL XR 50 MG TABLET | Generic | $5.63 each |
Ontology: lamotrigine (C0064636)
| Definition (NCI) | A synthetic phenyltriazine with antiepileptic and analgesic properties. Lamotrigine enhances the action of gamma-aminobutyric acid, an inhibitory neurotransmitter, which may result in a reduction of pain-related transmission of signals along nerve fibers. This agent may also inhibit voltage-gated sodium channels, suppress glutamate release, and inhibit serotonin reuptake. (NCI04) |
| Definition (NCI_NCI-GLOSS) | A drug that is used to help control some types of seizures. It is being studied in the prevention of peripheral neuropathy caused by some chemotherapy drugs. It belongs to the family of drugs called anticonvulsants. |
| Definition (PDQ) | A synthetic phenyltriazine with antiepileptic and analgesic properties. Lamotrigine enhances the action of gamma-aminobutyric acid, an inhibitory neurotransmitter, which may result in a reduction of pain-related transmission of signals along nerve fibers. This agent may also inhibit voltage-gated sodium channels, suppress glutamate release, and inhibit serotonin reuptake. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=328241&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=328241&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C38703" NCI Thesaurus) |
| Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
| MSH | C047781 |
| SnomedCT | 387562000, 96195007 |
| LNC | LP17251-7, MTHU012305 |
| English | 3,5-diamino-6-(2,3-dichlorophenyl)-as-triazine, lamotrigine (medication), LAMOTRIGINE, lamotrigine [Chemical/Ingredient], lamoTRIgine, LamoTRIgine, 3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine, lamotrigine, Lamotrigine, Lamotrigine (product), Lamotrigine (substance) |
| Spanish | lamotrigina (producto), lamotrigina (sustancia), lamotrigina |
Ontology: Lamictal (C0678180)
| Definition (CHV) | brand name of lamotrigine |
| Definition (CHV) | brand name of lamotrigine |
| Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
| MSH | C047781 |
| English | lamotrigine (Lamictal), lamictal, lamictal [brand name], LaMICtal, Lamiktal, Desitin Brand of Lamotrigine, Glaxo Wellcome Brand of Lamotrigine, GlaxoSmithKline Brand of Lamotrigine, Lamictal |
