Each patient should be given an individualized dose of Lamictal. Your healthcare provider determines the safe and effective Lamictal dosage depending on a number of factors that include the medical condition being treated, your age and weight, other medications currently taken and other underlying medical conditions.
This medication guide provides only the average dose of Lamictal as recommended by the manufacturer. Your healthcare provider may give you a totally different dosage. Do not adjust your dose unless instructed by your healthcare provider.
Lamictal dosing is quite complicated. It is important to inform your healthcare provider of all the drugs that you are currently taking, specifically other seizure or bipolar medications. These drugs are known to interfere with the metabolism and excretion of Lamictal which can lead to potentially serious side effects such as rash.
Dosage of Lamictal for Epilepsy
For patients (over 12 years of age) who are NOT TAKING valproic acid (Depakote, Depakene, Depacon, Stavzor), but are taking other anti-seizure drugs that can potentially decrease lamotrigine blood levels (such as carbamazepine, phenobarbital, phenytoin, and primidone), the recommended initial dose of Lamictal immediate release tablets is 50 mg taken once a day for the first two weeks, then increased to 50 mg taken twice a day for two weeks. The dose may further be increased by 100 mg per day after one or two weeks until the effective maintenance dose is reached. The recommended daily maintenance dose ranges from 300 to 500 mg taken in divided doses.
For patients (over 12 years of age) who are TAKING valproic acid, the recommended initial dosage of Lamictal is 25 mg taken every other day for two weeks, then increased to 25 mg once a day for two weeks. Thereafter, the dose can be increased gradually with increments of 25 to 50 mg per day every 1 to 2 weeks until the maximum dose of 400 mg per day is reached. The usual maintenance dose ranges from 200 to 400 mg per day.
When using extended release tablets, the maintenance dosage ranges from 200 to 600 mg taken once a day. Again, the dose should be slowly titrated until the effective dose is achieved.
Pediatric patients (2 to 12 years of age) are given an adjusted dose of Lamictal based on the patient’s weight and age.
Dosage of Lamictal for Bipolar Disorder
The recommended dose for prevention and management of bipolar disorder ranges from 100 to 400 mg per day. Patients taking other medications, particularly anti-seizure drugs, are given adjusted doses of Lamictal.
For patients taking valproate, the maximum dose is 100 mg per day. Meanwhile, for patients who are not taking valproate but are taking drugs that reduce lamotrigine blood levels (carbamazepine, phenytoin, phenobarbital, primidone, and other drugs such as rifampin), the recommended daily dose is 400 mg per day.
As mentioned above, Lamictal dosages need to be individualized to prevent possible adverse effects of this medication. Generally, this drug should be started at the lowest dose possible and then gradually increased. Be sure to read the prescription label and take this drug exactly as instructed. If you have any questions or do not understand the prescription, ask your healthcare provider. Lamictal dose adjustment can be confusing for some people therefore close coordination with your prescribing physician is necessary.