The goal of maintenance treatment with LAMICTAL 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. The target dose of LAMICTAL 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 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 LAMICTAL 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 If other psychotropic medications are withdrawn following stabilization, the dose of LAMICTAL should be adjusted. For patients discontinuing valproate, the dose of LAMICTAL should be doubled over a 2-week period in equal weekly increments (see Table 6). For patients discontinuing carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin that induce lamotrigine glucuronidation, the dose of LAMICTAL 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 LAMICTAL may then be further adjusted to the target dose (200 mg) as clinically indicated. 

If other drugs are subsequently introduced, the dose of LAMICTAL may need to be adjusted. In particular, the introduction of valproate requires reduction in the dose of LAMICTAL [see Drug Interactions (7), Clinical Pharmacology (12.3)].

To avoid an increased risk of rash, the recommended initial dose and subsequent dose escalations of LAMICTAL should not be exceeded [see Boxed Warning].

aValproate has been shown to inhibit glucuronidation and decrease the apparent clearance of lamotrigine [see Drug Interactions (7), Clinical Pharmacology (12.3)].

bThese drugs induce lamotrigine glucuronidation and increase clearance [see Drug Interactions (7), Clinical Pharmacology (12.3)]. Other drugs that have similar effects include estrogen-containing oral contraceptives [see Drug Interactions (7), Clinical Pharmacology (12.3)]. Dosing recommendations for oral contraceptives can be found in General Dosing Considerations [see Dosage and Administration (2.1)]. Patients on rifampin, or other drugs that induce lamotrigine glucuronidation and increase clearance, should follow the same dosing titration/maintenance regimen as that used with anticonvulsants that have this effect.

aValproate has been shown to inhibit glucuronidation and decrease the apparent clearance of lamotrigine [see Drug Interactions (7), Clinical Pharmacology (12.3)].

bThese drugs induce lamotrigine glucuronidation and increase clearance [see Drug Interactions (7), Clinical Pharmacology (12.3)]. Other drugs that have similar effects include estrogen-containing oral contraceptives [see Drug Interactions (7), Clinical Pharmacology (12.3)]. Dosing recommendations for oral contraceptives can be found in General Dosing Considerations [see Dosage and Administration (2.1)]. Patients on rifampin, or other drugs that induce lamotrigine glucuronidation and increase clearance, should follow the same dosing titration/maintenance regimen as that used with anticonvulsants that have this effect.

The benefit of continuing treatment in patients who had been stabilized in an 8- to 16-week open-label phase with LAMICTAL was established in 2 randomized, placebo-controlled clinical maintenance trials [see Clinical Studies (14.2)]. However, the optimal duration of treatment with LAMICTAL has not been established. Thus, patients should be periodically reassessed to determine the need for maintenance treatment.