Lamotrigine (Page 3 of 13)
2.3 Epilepsy – Conversion From Adjunctive Therapy to Monotherapy
The goal of the transition regimen is to attempt to maintain seizure control while mitigating the risk of serious rash associated with the rapid titration of lamotrigine tablets (chewable, dispersible).
The recommended maintenance dose of lamotrigine tablets (chewable, dispersible) as monotherapy is 500 mg/day given in 2 divided doses.
To avoid an increased risk of rash, the recommended initial dose and subsequent dose escalations for lamotrigine tablets (chewable, dispersible) should not be exceeded [see Boxed Warning].
Conversion From Adjunctive Therapy With Carbamazepine, Phenytoin, Phenobarbital, or Primidone to Monotherapy With Lamotrigine Tablets (Chewable, Dispersible)
After achieving a dose of 500 mg/day of lamotrigine tablets (chewable, dispersible) using the guidelines in Table 1 , the concomitant enzyme-inducing AED should be withdrawn by 20% decrements each week over a 4 week period. The regimen for the withdrawal of the concomitant AED is based on experience gained in the controlled monotherapy clinical trial.
Conversion From Adjunctive Therapy With Valproate to Monotherapy With Lamotrigine Tablets (Chewable, Dispersible)The conversion regimen involves the 4 steps outlined in Table 4.
Lamotrigine | Valproate | |
Step 1 | Achieve a dose of 200 mg/day according to guidelines in Table 1. | Maintain established stable dose. |
Step 2 | Maintain at 200 mg/day. | Decrease dose by decrements no greater than 500 mg/day/week to 500 mg/day and then maintain for 1 week. |
Step 3 | Increase to 300 mg/day and maintain for 1 week. | Simultaneously decrease to 250 mg/day and maintain for 1 week. |
Step 4 | Increase by 100 mg/day every week to achieve maintenance dose of 500 mg/day. | Discontinue. |
Conversion From Adjunctive Therapy With Antiepileptic Drugs Other Than Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate to Monotherapy With Lamotrigine Tablets (Chewable, Dispersible)No specific dosing guidelines can be provided for conversion to monotherapy with lamotrigine tablets (chewable, dispersible) with AEDs other than carbamazepine, phenytoin, phenobarbital, primidone, or valproate.
2.4 Bipolar Disorder
The goal of maintenance treatment with lamotrigine tablets (chewable, dispersible) is to delay the time to occurrence of mood episodes (depression, mania, hypomania, mixed episodes) in patients treated for acute mood episodes with standard therapy [see Indications and Usage (1) ].
Patients taking lamotrigine tablets (chewable, dispersible) for more than 16 weeks should be periodically reassessed to determine the need for maintenance treatment.
Adults
The target dose of lamotrigine tablets (chewable, dispersible) is 200 mg/day (100 mg/day in patients taking valproate, which decreases the apparent clearance of lamotrigine, and 400 mg/day in patients not taking valproate and taking either carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin and the protease inhibitor lopinavir/ritonavir that increase the apparent clearance of lamotrigine). In the clinical trials, doses up to 400 mg/day as monotherapy were evaluated; however, no additional benefit was seen at 400 mg/day compared with 200 mg/day [see Clinical Studies (14.2) ]. Accordingly, doses above 200 mg/day are not recommended.
Treatment with lamotrigine tablets (chewable, dispersible) is introduced, based on concurrent medications, according to the regimen outlined in Table 5. If other psychotropic medications are withdrawn following stabilization, the dose of lamotrigine tablets (chewable, dispersible) should be adjusted. In patients discontinuing valproate, the dose of lamotrigine tablets (chewable, dispersible) should be doubled over a 2 week period in equal weekly increments (see Table 6). In patients discontinuing carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin and the protease inhibitors lopinavir/ritonavir and atazanavir/ritonavir that induce lamotrigine glucuronidation, the dose of lamotrigine tablets (chewable, dispersible) should remain constant for the first week and then should be decreased by half over a 2 week period in equal weekly decrements (see Table 6). The dose of lamotrigine tablets (chewable, dispersible) may then be further adjusted to the target dose (200 mg) as clinically indicated.
If other drugs are subsequently introduced, the dose of lamotrigine tablets (chewable, dispersible) may need to be adjusted. In particular, the introduction of valproate requires reduction in the dose of lamotrigine tablets (chewable, dispersible) [see Drug Interactions (7), Clinical Pharmacology (12.3)].
To avoid an increased risk of rash, the recommended initial dose and subsequent dose escalations of lamotrigine tablets (chewable, dispersible) should not be exceeded [see Boxed Warning ].
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In Patients TAKING Valproate * | In Patients NOT TAKING Carbamazepine, Phenytoin, Phenobarbital, Primidone † , or Valproate * | In Patients TAKING Carbamazepine, Phenytoin, Phenobarbital, or Primidone † and NOT TAKING Valproate * | |
Weeks 1 and 2 | 25 mg every other day | 25 mg daily | 50 mg daily |
Weeks 3 and 4 | 25 mg daily | 50 mg daily | 100 mg daily, in divided doses |
Week 5 | 50 mg daily | 100 mg daily | 200 mg daily, in divided doses |
Week 6 | 100 mg daily | 200 mg daily | 300 mg daily, in divided doses |
Week 7 | 100 mg daily | 200 mg daily | up to 400 mg daily, in divided doses |
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Discontinuation of Psychotropic Drugs (excluding Valproate * , Carbamazepine, Phenytoin, Phenobarbital, or Primidone † ) | After Discontinuation of Valproate * | After Discontinuation of Carbamazepine, Phenytoin, Phenobarbital, or Primidone † | |
Current dose of Lamotrigine (mg/day) 100 | Current dose of Lamotrigine (mg/day) 400 | ||
Week 1 | Maintain current dose of lamotrigine | 150 | 400 |
Week 2 | Maintain current dose of lamotrigine | 200 | 300 |
Week 3 onward | Maintain current dose of lamotrigine | 200 | 200 |
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