LAMOTRIGINE (Page 2 of 12)

2.2 Epilepsy – Adjunctive Therapy

This section provides specific dosing recommendations for patients older than 12 years and patients aged 2 to 12 years. Within each of these age-groups, specific dosing recommendations are provided depending upon concomitant AED or other concomitant medications (see Table 1 for patients older than 12 years and Table 2 for patients aged 2 to 12 years). A weight-based dosing guide for patients aged 2 to 12 years of age on concomitant valproate is provided in Table 3.

Patients Older than 12 Years Recommended dosing guidelines are summarized in Table 1.

Table 1. Escalation Regimen for Lamotrigine in Patients Older than 12 Years with Epilepsy

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

b Drugs that induce lamotrigine glucuronidation and increase clearance, other than the specified antiepileptic drugs, include estrogen containing oral contraceptives, rifampin, and the protease inhibitors lopinavir/ritonavir and atazanavir/ritonavir can be found in General Dosing Considerations [see Dosage and Administration (2.1)]. Patients on rifampin and the protease inhibitor lopinavir/ritonavir should follow the same dosing titration/maintenance regimen used with antiepileptic drugs that induce glucuronidation and increase clearance [see Dosage and Administration (2.1), Drug Interactions (7), Clinical Pharmacology (12.3)].

In Patients TAKING Valproatea In Patients NOT TAKING Carbamazepine, Phenytoin, Phenobarbital, Primidone,b or Valproatea In Patients TAKING Carbamazepine, Phenytoin, Phenobarbital, or Primidoneb and NOT TAKING Valproatea
Weeks 1 and 2 25 mg every other day 25 mg every day 50 mg/day
Weeks 3 and 4 25 mg every day 50 mg/day 100 mg/day (in 2 divided doses)
Weeks 5 onwards to maintenance Increase by 25 to 50 mg/day every 1 to 2 weeks Increase by 50 mg/day every 1 to 2 weeks Increase by 100 mg/day every 1 to 2 weeks
Usual Maintenance dose 100 to 200 mg/day with valproate alone 100 to 400 mg/day with valproate and other drugs that induce glucuronidation (in 1 or 2 divided doses) 225 to 375 mg/day (in 2 divided doses) 300 to 500 mg/day (in 2 divided doses)

Patients Aged 2 to 12 Years Recommended dosing guidelines are summarized in Table 2.

Lower starting doses and slower dose escalations than those used in clinical trials are recommended because of the suggestion that the risk of rash may be decreased by lower starting doses and slower dose escalations. Therefore, maintenance doses will take longer to reach in clinical practice than in clinical trials. It may take several weeks to months to achieve an individualized maintenance dose. Maintenance doses in patients weighing < 30 kg, regardless of age or concomitant AED, may need to be increased as much as 50%, based on clinical response.

Table 2. Escalation Regimen for Lamotrigine in Patients Aged 2 to 12 Years with Epilepsy

Note: Only whole tablets should be used for dosing.

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

b Drugs that induce lamotrigine glucuronidation and increase clearance other than the specified antiepileptic drugs, include estrogen-containing oral contraceptives, rifampin, and the protease inhibitors lopinavir/ritonavir and atazanavir/ritonavir. Dosing recommendations for oral contraceptives and the protease inhibitor atazanavir/ritonavir can be found in General Dosing Considerations [see Dosage and Administration (2.1)]. Patients on rifampin, and the protease inhibitor lopinavir/ritonavir should follow the same dosing titration/maintenance regimen used with antiepileptic drugs that induce glucuronidation and increase clearance [see Dosage and Administration (2.1), Drug Interactions (7), and Clinical Pharmacology (12.3)].

In Patients TAKING Valproatea In Patients NOT TAKING Carbamazepine, Phenytoin, Phenobarbital, Primidone,b or Valproatea In Patients TAKING Carbamazepine, Phenytoin, Phenobarbital, or Primidoneb and NOT TAKING Valproatea
Weeks 1 and 2 0.15 mg/kg/day in 1 or 2 divided doses, rounded down to the nearest whole tablet (see Table 3 for weight-based dosing guide) 0.3 mg/kg/day in 1 or 2 divided doses, rounded down to the nearest whole tablet 0.6 mg/kg/day in 2 divided doses, rounded down to the nearest whole tablet
Weeks 3 and 4 0.3 mg/kg/day in 1 or 2 divided doses, rounded down to the nearest whole tablet (see Table 3 for weight-based dosing guide) 0.6 mg/kg/day in 2 divided doses, rounded down to the nearest whole tablet 1.2 mg/kg/day in 2 divided doses, rounded down to the nearest whole tablet
Weeks 5 onwards to maintenance The dose should be increased every 1 to 2 weeks as follows: calculate 0.3 mg/kg/day, round this amount down to the nearest whole tablet, and add this amount to the previously administered daily dose. The dose should be increased every 1 to 2 weeks as follows: calculate 0.6 mg/kg/day, round this amount down to the nearest whole tablet, and add this amount to the previously administered daily dose. The dose should be increased every 1 to 2 weeks as follows: calculate 1.2 mg/kg/day, round this amount down to the nearest whole tablet, and add this amount to the previously administered daily dose.
Usual maintenance dose 1 to 5 mg/kg/day (maximum 200 mg/day in 1 or 2 divided doses). 1 to 3 mg/kg/day with valproate alone 4.5 to 7.5 mg/kg/day (maximum 300 mg/day in 2 divided doses) 5 to 15 mg/kg/day (maximum 400 mg/day in 2 divided doses)
Maintenance dose in patients <30 kg May need to be increased by as much as 50%, based on clinical response May need to be increased by as much as 50%, based on clinical response May need to be increased by as much as 50%, based on clinical response
Table 3. The Initial Weight-Based Dosing Guide for Patients Aged 2 to 12 Years Taking Valproate (Weeks 1 to 4) with Epilepsy
If the patient’s weight is Give this daily dose, using the most appropriate combination of Lamotrigine 2-mg and 5-mg tablets
Greater than And less than Weeks 1 and 2 Weeks 3 and 4
6.7 kg 14 kg 2 mg every other day 2 mg every day
14.1 kg 27 kg 2 mg every day 4 mg every day
27.1 kg 34 kg 4 mg every day 8 mg every day
34.1 kg 40 kg 5 mg every day 10 mg every day

Usual Adjunctive Maintenance Dose for Epilepsy: The usual maintenance doses identified in Tables 1 and 2 are derived from dosing regimens employed in the placebo-controlled adjunctive trials in which the efficacy of lamotrigine was established. In patients receiving multidrug regimens employing carbamazepine, phenytoin, phenobarbital, or primidone without valproate, maintenance doses of adjunctive lamotrigine as high as 700 mg/day have been used. In patients receiving valproate alone, maintenance doses of adjunctive lamotrigine as high as 200 mg/day have been used. The advantage of using doses above those recommended in Tables 1-4 has not been established in controlled trials.

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