Lamictal Dosage/Direction for Use

Pharmaceutical form: Tablets and Dispersible/Chewable tablets.
Lamictal tablets should be swallowed whole, and should not be chewed or crushed.
Lamictal dispersible/chewable tablets may be chewed, dispersed in a small volume of water (at least enough to cover the whole tablet) or swallowed whole with a little water.
Do not attempt to administer partial quantities of the dispersible/chewable tablets.
If a calculated dose of Lamictal e.g. for use in children (epilepsy only) or patients with hepatic impairment, cannot be divided into multiple lower strength tablets, the dose to be administered is that equal to the nearest lower strength of whole tablets.
Restarting Therapy: Prescribers should assess the need for escalation to maintenance dose when restarting Lamictal in patients who have discontinued Lamictal for any reason, since the risk of serious rash is associated with high initial doses and exceeding the recommended dose escalation for Lamictal (see Precautions). The greater the interval of time since the previous dose, the more consideration should be given to escalation to the maintenance dose. When the interval since discontinuing Lamictal exceeds five half-lives (see Pharmacokinetics under Actions), Lamictal should generally be escalated to the maintenance dose according to the appropriate schedule.
It is recommended that Lamictal not be restarted in patients who have discontinued due to rash associated with prior treatment with Lamictal unless the potential benefit clearly outweighs the risk.
Epilepsy: When concomitant antiepileptic drugs are withdrawn to achieve Lamictal monotherapy or other AEDs are added-on to treatment regimens containing lamotrigine, consideration should be given to the effect this may have on lamotrigine pharmacokinetics (see Interactions).
Dosage in epilepsy monotherapy: Adults and adolescents (over 12 years of age) (see Table 1): The initial Lamictal dose in monotherapy is 25 mg once daily for two weeks, followed by 50 mg once a day for two weeks. Thereafter, the dose should be increased by a maximum of 50 to 100 mg every one to two weeks until the optimal response is achieved. The usual maintenance dose to achieve optimal response is 100 to 200 mg/day given once a day or as two divided doses. Some patients have required 500 mg/day of Lamictal to achieve the desired response.
Because of a risk of rash, the initial dose and subsequent dose escalation should not be exceeded (see Precautions).
Dosage in epilepsy add-on therapy: Adults and adolescents (over 12 years of age) (see Table 1): In patients taking valproate with/without any other AED, the initial Lamictal dose is 25 mg every alternate day for two weeks, followed by 25 mg once daily for two weeks. Thereafter, the dose should be increased by a maximum of 25-50 mg every one to two weeks until the optimal response is achieved. The usual maintenance dose to achieve optimal response is 100 to 200 mg/day given once a day or in two divided doses.
In those patients taking concomitant AEDs or other medications (see Interactions) that induce lamotrigine glucuronidation with/without other AEDs (except valproate), the initial Lamictal dose is 50 mg once a day for two weeks, followed by 100 mg/day given in two divided doses for two weeks.
Thereafter, the dose should be increased by a maximum of 100 mg every one to two weeks until the optimal response is achieved. The usual maintenance dose to achieve optimal response is 200 to 400 mg/day given in two divided doses.
Some patients have required 700 mg/day of Lamictal to achieve the desired response.
In those patients taking other medications that do not significantly inhibit or induce lamotrigine glucuronidation (see Interactions), the initial Lamictal dose is 25 mg once a day for two weeks, followed by 50 mg once a day for two weeks. Thereafter, the dose should be increased by a maximum of 50 to 100 mg every one to two weeks until the optimal response is achieved. The usual maintenance dose to achieve an optimal response is 100 to 200 mg/day given once a day or as two divided doses. (See Table 1.)


Click on icon to see table/diagram/image


Because of a risk of rash, the initial dose and subsequent dose escalation should not be exceeded (see Precautions).
Children (2 to 12 years of age) (see Table 2): In patients taking valproate with/without any other AED, the initial Lamictal dose is 0.15 mg/kg bodyweight/day given once a day for two weeks, followed by 0.3 mg/kg/day once a day for two weeks. Thereafter, the dose should be increased by a maximum of 0.3 mg/kg every one to two weeks until the optimal response is achieved. The usual maintenance dose to achieve optimal response is 1 to 5 mg/kg/day given once a day or in two divided doses, with a maximum of 200 mg/day.
In those patients taking concomitant AEDs or other medications (see Interactions) that induce lamotrigine glucuronidation with/without other AEDs (except valproate), the initial Lamictal dose is 0.6 mg/kg bodyweight/day given in two divided doses for two weeks, followed by 1.2 mg/kg/day given in two divided doses for two weeks. Thereafter, the dose should be increased by a maximum of 1.2 mg/kg every one to two weeks until the optimal response is achieved. The usual maintenance dose to achieve optimal response is 5 to 15 mg/kg/day given in two divided doses, with a maximum of 400 mg/day.
In patients taking other medications that do not significantly inhibit or induce lamotrigine glucuronidation (see Interactions), the initial Lamictal dose is 0.3 mg/kg bodyweight/day given once a day or in two divided doses for two weeks, followed by 0.6 mg/kg/day given once a day or in two divided doses for two weeks. Thereafter, the dose should be increased by a maximum of 0.6 mg/kg every one to two weeks until the optimal response is achieved. The usual maintenance dose to achieve optimal response is 1 to 10 mg/kg/day given once a day or in two divided doses, with a maximum of 200 mg/day.
To ensure a therapeutic dose is maintained the weight of a child must be monitored and the dose reviewed as weight changes occur. (See Table 2.)


Click on icon to see table/diagram/image


Because of a risk of rash, the initial dose and subsequent dose escalation should not be exceeded (see Precautions). It is likely that patients aged two to six years will require a maintenance dose at the higher end of the recommended range.
Children aged less than 2 years: There is insufficient information on the use of Lamictal in children aged less than two years.
Bipolar Disorder: Adults (18 years of age and over): Because of the risk of rash, the initial dose and subsequent dose escalation should not be exceeded (see Precautions).
Lamictal is recommended for use in bipolar patients at risk for a future depressive episode.
The following transition regimen should be followed to prevent recurrence of depressive episodes. The transition regimen involves escalating the dose of Lamictal to a maintenance stabilisation dose over six weeks (see Table 3) after which other psychotropic and/or antiepileptic drugs can be withdrawn, if clinically indicated (see Table 4).
Adjunctive therapy should be considered for the prevention of manic episodes, as efficacy with Lamictal in mania has not been conclusively established. (See Table 3.)


Click on icon to see table/diagram/image


a) Adjunct therapy with inhibitors of lamotrigine glucuronidation e.g. valproate: In patients taking glucuronidation inhibiting concomitant drugs such as valproate, the initial Lamictal dose is 25 mg every alternate day for two weeks, followed by 25 mg once a day for two weeks. The dose should be increased to 50 mg once a day (or in two divided doses) in week 5. The usual target dose to achieve optimal response is 100 mg/day given once a day or in two divided doses. However, the dose can be increased to a maximum daily dose of 200 mg, depending on clinical response.
b) Adjunct therapy with inducers of lamotrigine glucuronidation in patients not taking inhibitors such as valproate: This dosage regimen should be used with phenytoin, carbamazepine, phenobarbitone, primidone and other drugs known to induce lamotrigine glucuronidation (see Interactions). In those patients currently taking drugs that induce lamotrigine glucuronidation and not taking valproate, the initial Lamictal dose is 50 mg once a day for two weeks, followed by 100 mg/day given in two divided doses for two weeks. The dose should be increased to 200 mg/day given as two divided doses in week 5. The dose may be increased in week 6 to 300 mg/day. However, the usual target dose to achieve optimal response is 400 mg/day given in two divided doses which may be given from week 7.
c) Monotherapy with Lamictal or adjunctive therapy in patients taking other medications that do not significantly induce or inhibit lamotrigine glucuronidation (see Interactions): The initial Lamictal dose is 25 mg once a day for two weeks, followed by 50 mg once a day (or in two divided doses) for two weeks. The dose should be increased to 100 mg/day in week 5. The usual target dose to achieve optimal response is 200 mg/day given once a day or as two divided doses. However, a range of 100 to 400 mg was used in clinical trials.
Once the target daily maintenance stabilisation dose has been achieved, other psychotropic medications may be withdrawn as laid out in the dosage schedule as follows (see Table 4).


Click on icon to see table/diagram/image


(a) Following withdrawal of adjunct therapy with inhibitors of lamotrigine glucuronidation e.g. valproate: The dose of Lamictal should be increased to double the original target stabilisation dose and maintained at this, once valproate has been terminated.
(b) Following withdrawal of adjunct therapy with inducers of lamotrigine glucuronidation depending on original maintenance dose: This regimen should be used with phenytoin, carbamazepine, phenobarbitone, primidone or other drugs known to induce Lamictal glucuronidation (see Interactions). The dose of Lamictal should be gradually reduced over three weeks as the glucuronidation inducer is withdrawn.
(c) Following withdrawal of adjunct therapy with other medications that do not significantly inhibit or induce lamotrigine glucuronidation (see Interactions): The target dose achieved in the dose escalation programme should be maintained throughout withdrawal of the other medication.
Adjustment of Lamictal daily dosing in patients with Bipolar Disorder following addition of other medications: There is no clinical experience in adjusting the Lamictal daily dose following the addition of other medications. However, based on drug interaction studies, the following recommendations can be made (see Table 5).


Click on icon to see table/diagram/image


Discontinuation of Lamictal in adult patients with Bipolar Disorder: In clinical trials, there was no increase in the incidence, severity or type of adverse experiences following abrupt termination of Lamictal versus placebo. Therefore, patients may terminate Lamictal without a stepwise reduction of dose.
Children and adolescents (less than 18 years of age): Lamictal is not indicated for use in bipolar disorder in children and adolescents aged less than 18 years (see Precautions). Safety and efficacy of Lamictal in bipolar disorder has not been established in this age group. Therefore, a dosage recommendation cannot be made.
General Dosing Recommendations for Lamictal in Special Patient Populations: Women taking hormonal contraceptives: (a) Starting Lamictal in patients already taking hormonal contraceptives: Although an oral contraceptive has been shown to increase the clearance of lamotrigine (see Precautions and Interactions), no adjustments to the recommended dose escalation guidelines for Lamictal should be necessary solely based on the use of hormonal contraceptives. Dose escalation should follow the recommended guidelines based on whether lamotrigine is added to valproate (an inhibitor of lamotrigine glucuronidation), or to an inducer of lamotrigine glucuronidation, or whether Lamictal is added in the absence of valproate, or an inducer of lamotrigine glucuronidation (see Table 1 for epilepsy and Table 3 for bipolar patients).
(b) Starting hormonal contraceptives in patients already taking maintenance doses of Lamictal and not taking inducers of lamotrigine glucuronidation: The maintenance dose of Lamictal will in most cases need to be increased by as much as two-fold (see Precautions and Interactions).
(c) Stopping hormonal contraceptives in patients already taking maintenance doses of Lamictal and not taking inducers of lamotrigine glucuronidation: The maintenance dose of Lamictal will in most cases need to be decreased by as much as 50% (see Precautions and Interactions).
Use with atazanavir/ritonavir: Although atazanavir/ritonavir has been shown to reduce lamotrigine plasma concentrations (see Interactions), no adjustments to the recommended dose escalation guidelines for Lamictal should be necessary solely based on the use of atazanavir/ritonavir. Dose escalation should follow the recommended guidelines based on whether Lamictal is added to valproate (an inhibitor of lamotrigine glucuronidation), or to an inducer of lamotrigine glucuronidation, or whether Lamictal is added in the absence of valproate or an inducer of lamotrigine glucuronidation.
In patients already taking maintenance doses of Lamictal and not taking glucuronidation inducers, the Lamictal dose may need to be increased if atazanavir/ritonavir is added, or decreased if atazanavir/ritonavir is discontinued.
Elderly (over 65 years of age): No dosage adjustment from recommended schedule is required. The pharmacokinetics of Lamictal in this age group do not differ significantly from a non-elderly adult population.
Hepatic impairment: Initial, escalation and maintenance doses should generally be reduced by approximately 50% in patients with moderate (Child-Pugh grade B) and 75% in severe (Child-Pugh grade C) hepatic impairment. Escalation and maintenance doses should be adjusted according to clinical response (see Pharmacokinetics under Actions).
Renal Impairment: Caution should be exercised when administering Lamictal to patients with renal failure. For patients with end-stage renal failure, initial doses of Lamictal should be based on patient's AED regimen; reduced maintenance doses may be effective for patients with significant renal functional impairment (see Pharmacokinetics under Actions and Precautions).