Lamotrigine (US brand name Lamictal® and generic) is an anticonvulsant that is used in the treatment of bipolar I disorder. Here is basic information about this medication.
Maintenance treatment of bipolar I disorder to delay the time to occurrence of mood episodes in patients treated for acute mood episodes with standard therapy
1. Dosing regimen in adult patients with bipolar disorder
a. In patients not taking carbamazepine, phenytoin, phenobarbital, primidone, or valproate
Weeks 1 and 2: 25 mg daily
Weeks 3 and 4: 50 mg daily
Week 5: 100 mg daily
Week 6: 200 mg daily
Week 7: 200 mg daily
b. In patients taking valproate
Weeks 1 and 2: 25 mg every other day
Weeks 3 and 4: 25 mg daily
Week 5: 50 mg daily
Week 6: 100 mg daily
Week 7: 100 mg daily
c. In patients taking carbamazepine, phenytoin, phenobarbital, or primidone and not taking valproate
Weeks 1 and 2: 50 mg daily
Weeks 3 and 4: 100 mg daily, in divided doses
Week 5: 200 mg daily, in divided doses
Week 6: 300 mg daily, in divided doses
Week 7: up to 400 mg daily, in divided doses
2. Dosage adjustments to lamotrigine in adults with bipolar disorder following discontinuation of psychotropic medications
a. Discontinuation of psychotropic drugs (excluding valproate, carbamazepine, phenytoin, phenobarbital, or primidone)
Week 1: Maintain current dose of lamotrigine
Week 2: Maintain current dose of lamotrigine
Week 3 onward: Maintain current dose of lamotrigine
b. After discontinuation of valproate (current dose of lamotrigine 100 mg/day)
Week 1: 150 mg/day
Week 2: 200 mg/day
Week 3 onward: 200 mg/day
c. After discontinuation of carbamazepine, phenytoin, phenobarbital, or primidone (current dose of lamotrigine 400 mg/day)
Week 1: 400 mg/day
Week 2: 300 mg/day
Week 3 onward: 200 mg/day
Important information to remember
1. Treatment of acute manic or mixed episodes is not recommended with lamotrigine.
2. To avoid the incidence of life-threatening rash, do not: administer with valproate, exceed recommended initial dose, or exceed recommended dose escalation.
3. Valproate increases lamotrigine concentrations more than 2-fold. Carbamazepine, phenytoin, phenobarbital, primidone, and rifampin decrease lamotrigine concentrations by approximately 40%. Estrogen-containing oral contraceptives decrease lamotrigine concentrations by approximately 50%. Protease inhibitors lopinavir/ritonavir and atazanavir/lopinavir decrease lamotrigine exposure by approximately 50% and 32%, respectively.
4. Dosage adjustment may be needed in moderate and severe hepatic impairment.
5. Reduced maintenance doses of lamotrigine may be needed in significant renal impairment.
Elderly: There is no clear research data, but the official Prescribing Information does urge a bit of caution: “Clinical studies of LAMICTAL for epilepsy and in Bipolar Disorder did not include sufficient numbers of subjects 65 years of age and over to determine whether they respond differently from younger subjects or exhibit a different safety profile than that of younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. “
Dosage forms and strengths
Scored tablets: 25 mg, 100 mg, 150 mg, and 200 mg.
Chewable dispersible tablets: 2 mg, 5 mg, and 25 mg.
Orally disintegrating tablets: 25 mg, 50 mg, 100 mg, and 200 mg.
Please refer to Prescribing Information (see link below) for complete discussion of dosage, administration, warnings and precautions, contraindications, etc.
Copyright 2015, Rajnish Mago, MD. All rights reserved. May not be reproduced in any form without express written permission.
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