No

Anticonvulsant, Miscellaneous

Adjunctive therapy in the treatment of partial seizures in adults with epilepsy (safety and effectiveness in children <16 years of age have not been established); adjunctive therapy in the generalized seizures of Lennox-Gastaut syndrome in pediatric and adult patients; conversion to monotherapy in adults with partial seizures who are receiving treatment with a single enzyme-inducing antiepileptic drug

C

Hypersensitivity to lamotrigine or any component

Lactation, impaired renal, hepatic, or cardiac function; avoid abrupt cessation, taper over at least 2 weeks if possible. Severe and potentially life-threatening skin rashes have been reported; this appears to occur most frequently in pediatric patients. May cause CNS depression, which may impair physical or mental abilities. Patients must be cautioned about performing tasks which require mental alertness (ie, operating machinery or driving). Effects with other sedative drugs or ethanol may be potentiated. Write/fill Rx carefully. Confusion has occurred between Lamictal® (lamotrigine) and Lamisil® (terbinafine).

>10%:

Central nervous system: Headache, nausea, dizziness, ataxia, somnolence

Ocular: Diplopia, blurred vision

Respiratory: Rhinitis

1% to 10%:

Cardiovascular: Hot flashes, palpitations

Central nervous system: Depression, anxiety, irritability, confusion, speech disorder, difficulty concentrating, emotional lability, malaise, seizure, incoordination, insomnia

Dermatologic: Hypersensitivity rash, Stevens-Johnson syndrome, angioedema, pruritus, alopecia, acne

Gastrointestinal: Abdominal pain, vomiting, diarrhea, dyspepsia, constipation, psoriasis, xerostomia

Genitourinary: Vaginitis, amenorrhea

Neuromuscular & skeletal: Tremor, arthralgia, joint pain

Ocular: Nystagmus, diplopia

Renal: Hematuria

Respiratory: Cough

Miscellaneous: Flu syndrome, fever

Decontaminate using lavage/activated charcoal with cathartic

Multiple dosing of activated charcoal may be useful

Lamotrigine may increase the epoxide metabolite of carbamazepine resulting in toxicity

Carbamazepine, phenytoin, phenobarbital may decrease concentrations of lamotrigine

Valproic acid inhibits the metabolism of lamotrigine

Lamotrigine enhances the metabolism of valproic acid

A triazine derivative which inhibits release of glutamate (an excitatory amino acid) and inhibits voltage-sensitive sodium channels, which stabilizes neuronal membranes. Lamotrigine has weak inhibitory effect on the 5HT₃ receptor; in vitro inhibits dihydrofolate reductase.

Distribution: V_d: 1.1 L/kg

Protein binding: 55%

Metabolism: Hepatic and renal

Half-life: 24 hours; increases to 59 hours with concomitant valproic acid therapy; decreases with concomitant phenytoin or carbamazepine therapy to 15 hours

Peak levels: Within 1-4 hours

Elimination: In urine as the glucuronide conjugate

Oral:

With concomitant valproic acid therapy and other AED: 25 mg every other day for 2 weeks; 25 mg/day for 2 weeks; thereafter, dose may be increased by 25-50 mg/day every 1-2 weeks to 150 mg/day given in 2 divided doses

Food: Has no effect on absorption, take without regard to meals; drug may cause GI upset

Seizure (frequency and duration); serum levels of concurrent anticonvulsants; hypersensitivity reactions (especially rash)

Therapeutic range: 2-4 mg/mL

May cause sedation

Currently being studied in bipolar disorder; may be particularly useful for depressive phase of bipolar illness; valproic acid decreases clearance of lamotrigine; carbamazepine may decrease effects of lamotrigine

No information available to require special precautions

No effects or complications reported

Take exactly as directed (do not increase dose or frequency or discontinue without consulting prescriber). While using this medication, do not use alcohol and other prescription or OTC medications (especially pain medications, sedatives, antihistamines, or hypnotics) without consulting prescriber. Maintain adequate hydration (2-3 L/day of fluids unless instructed to restrict fluid intake). You may experience drowsiness, dizziness, or blurred vision (use caution when driving or engaging in tasks requiring alertness until response to drug is known); nausea, vomiting, loss of appetite, heartburn, or dry mouth (small frequent meals, frequent mouth care, chewing gum, or sucking lozenges may help). Wear identification of epileptic status and medications. Report CNS changes, mentation changes, or changes in cognition; persistent GI symptoms (cramping, constipation, vomiting, anorexia); skin rash; swelling of face, lips, or tongue; easy bruising or bleeding (mouth, urine, stool); vision changes; worsening of seizure activity, or loss of seizure control. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to be pregnant. Breast-feeding is not recommended.

Low water solubility

Tablet: 25 mg, 100 mg, 150 mg, 200 mg

Tablet, dispersible, chewable: 5 mg, 25 mg

A 1 mg/mL oral suspension was stable for 28 days stored at room temperature when compounded as follows:

Shake well before using and keep in refrigerator

Stability information from Glaxo Wellcome Co.

Battino D, Estienne M, and Avanzini G, "Clinical Pharmacokinetics of Antiepileptic Drugs in Paediatric Patients: Part II. Phenytoin, Carbamazepine, Sulthiame, Lamotrigine, Vigabatrin, Oxcarbazepine, and Felbamate," Clin Pharmacokinet, 1995, 29(5):341-69.

Besag FM, Wallace SJ, Dulac O, et al, "Lamotrigine for the Treatment of Epilepsy in Childhood," J Pediatr, 1995, 127(6):991-7.

Brodie MJ, "Lamotrigine," Lancet, 1992, 339(8806):1397-400.

Burstein AH, "Lamotrigine," Pharmacotherapy, 1995, 15(2):129-43.

Dooley J, Camfield P, Gordon K, et al, "Lamotrigine-Induced Rash in Children," Neurology, 1996, 46(1):240-2.

Fitton A, and Goa KL, "Lamotrigine: An Update of its Pharmacology and Therapeutic Use in Epilepsy," Drugs, 1995, 50(4):691-713.

Garnett WR and Pellock JM, "Focus on Lamotrigine: A New Antiepileptic Drug for Patients With Partial Seizures," Hosp Formul, 1994, 29:806-12.

Gilman JT, "Lamotrigine: An Antiepileptic Agent for the Treatment of Partial Seizures," Ann Pharmacother, 1995, 29(2):144-51.

Goa KL, Ross SR, and Chrisp P, "Lamotrigine: A Review of Its Pharmacological Properties and Clinical Efficacy in Epilepsy," Drugs, 1993, 46(1):152-76.

Messenheimer JA, "Lamotrigine," Epilepsia, 1995, 36(Suppl 2):S87-94.

Schirop Th, Lufft H, Winkler M, et al, "Bronchial Mucosa Reaction in Lyell-Stevens-Johnson Syndrome Following Lamotrigine," Intensivmedizin und Notfallmedizin, 1994, 31:343.