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Lamotrigine (Lamictal®): Basic prescribing information

Lamotrigine (US brand name Lamictal®, Lamictal CD®, Lamictal ODT® and generic) is an anticonvulsant that is used in the treatment of bipolar I disorder.

On this page, we will provide basic information about this medication. Links to other articles on this website with more advanced information and tips related to this medication and related topics are provided below—under Related Pages below.


FDA-approved indications

Maintenance treatment of bipolar I disorder to delay the time to occurrence of mood episodes in patients treated for acute mood episodes with standard therapy


Mechanism of Action/ Pharmacodynamics

The Prescribing Information notes that, “The mechanisms by which lamotrigine exerts its therapeutic action in bipolar disorder have not been established.”

What we do know is that lamotrigine inhibits voltage-sensitive sodium channels, which stabilizes neuronal membranes. This, in turn, modulates the release of excitatory amino acids like glutamate and aspartate from presynaptic neurons.


Dosage

1. Dosing regimen in adult patients with bipolar disorder

a. In patients not taking carbamazepine, phenytoin, phenobarbital, primidone, or valproate

Weeks 1 and 2: 25 mg daily

Weeks 3 and 4: 50 mg daily

Week 5: 100 mg daily

Week 6: 200 mg daily

Week 7: 200 mg daily


b. In patients taking valproate

Weeks 1 and 2: 25 mg every other day

Weeks 3 and 4: 25 mg daily

Week 5: 50 mg daily

Week 6: 100 mg daily

Week 7: 100 mg daily


c. In patients taking carbamazepine, phenytoin, phenobarbital, or primidone and not taking valproate

Weeks 1 and 2: 50 mg daily

Weeks 3 and 4: 100 mg daily, in divided doses

Week 5: 200 mg daily, in divided doses

Week 6: 300 mg daily, in divided doses

Week 7: up to 400 mg daily, in divided doses


2. Dosage adjustments to lamotrigine in adults with bipolar disorder following discontinuation of psychotropic medications

a. Discontinuation of psychotropic drugs (excluding valproate, carbamazepine, phenytoin, phenobarbital, or primidone)

Week 1: Maintain the current dose of lamotrigine

Week 2: Maintain the current dose of lamotrigine

Week 3 onward: Maintain the current dose of lamotrigine


b. After discontinuation of valproate (current dose of lamotrigine 100 mg/day)

Week 1: 150 mg/day

Week 2: 200 mg/day

Week 3 onward: 200 mg/day


c. After discontinuation of carbamazepine, phenytoin, phenobarbital, or primidone (current dose of lamotrigine 400 mg/day)

Week 1: 400 mg/day

Week 2: 300 mg/day

Week 3 onward: 200 mg/day


Important information to remember

1. Treatment of acute manic or mixed episodes is not recommended with lamotrigine.

2. To reduce the risk of life-threatening rash, do not: administer with valproate, exceed the recommended initial dose, or exceed the recommended dose escalation.

3. Valproate increases lamotrigine concentrations more than 2-fold. Carbamazepine, phenytoin, phenobarbital, primidone, and rifampin decrease lamotrigine concentrations by approximately 40%. Estrogen-containing oral contraceptives decrease lamotrigine concentrations by approximately 50%. Protease inhibitors lopinavir/ritonavir and atazanavir/lopinavir decrease lamotrigine exposure by approximately 50% and 32%, respectively.

4. Dosage adjustment may be needed in moderate and severe hepatic impairment.

5. Reduced maintenance doses of lamotrigine may be needed in significant renal impairment.

Elderly: There is no clear research data, but the official Prescribing Information does urge a bit of caution: “Clinical studies of LAMICTAL for epilepsy and in Bipolar Disorder did not include sufficient numbers of subjects 65 years of age and over to determine whether they respond differently from younger subjects or exhibit a different safety profile than that of younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. “


Dosage forms and strengths

Scored tablets (Lamictal® and generic): 25 mg, 100 mg, 150 mg, and 200 mg.

Chewable dispersible tablets (Lamictal CD® and generic): 2 mg, 5 mg, and 25 mg.

Orally disintegrating tablets (Lamictal ODT® and generic): 25 mg, 50 mg, 100 mg, and 200 mg.


Important! Prescribing clinicians must refer to the full Prescribing Information (see link below) for a complete discussion of dosage, administration, warnings and precautions, contraindications, etc.


Related Pages

Lamotrigine (Lamictal®): Basic Information

Can lamotrigine monotherapy be used for maintenance treatment in bipolar I disorder?

Lamotrigine: No additional benefit at 400 mg per day?

Why don’t we routinely prescribe lamotrigine extended-release (Lamictal XR®)?

How to add valproate to lamotrigine

Tips on using lamotrigine for mood disorders: Interview with Dr. Nassir Ghaemi


Starting lamotrigine

How to start and titrate lamotrigine (Lamictal®)

Dermatological precautions when starting lamotrigine


Restarting lamotrigine

Restarting lamotrigine

If lamotrigine is missed for a few days

Restarting lamotrigine: how many days?

Restarting lamotrigine: A case study


Lamotrigine and skin rash

Dermatological precautions when starting lamotrigine

Is it a benign or dangerous skin rash?

How common are benign and serious rashes with lamotrigine?

Lamotrigine rechallenge after a skin rash?


Lamotrigine side effects (other than skin rash)

Can lamotrigine levels predict adverse effects? 

What to do about the risk of arrhythmias with lamotrigine

Can lamotrigine cause psychiatric side effects?

Can lamotrigine cause bruising?

Is the use of lamotrigine during pregnancy safe?

Oral sores in a patient on lamotrigine 


Drug interactions with lamotrigine

5 Action Items about OCs and lamotrigine

Does lamotrigine decrease the effectiveness of oral contraceptives?

How to reduce lamotrigine when an inducer is stopped

Folic acid may counteract the benefit of lamotrigine


References

Prescribing Information: Lamotrigine (Lamictal®)

Lamotrigine: Patient information on Medlineplus.gov


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Disclaimer: The material on this website is provided as general education for medical professionals. It is not intended or recommended for patients or other laypersons or as a substitute for medical advice, diagnosis, or treatment. Patients must always consult a qualified healthcare professional regarding their diagnosis and treatment. Healthcare professionals should always check this website for the most recently updated information.

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Comments

  1. Rachel Abarbanel says

    August 18, 2020 at 4:55 pm

    Have you encountered clients stating that lamotrigine (Lamictal) is making their depression worse? I have had quite a few clients tell me this and it has been difficult to parse out if it is their condition worsening or an adverse effect. Some anticonvulsants such as levetiracetam (Keppra) have been known to worsen depression, so it might not be such a wild phenomenon. Thoughts?

    Reply
    • Rajnish Mago, MD says

      August 21, 2020 at 9:16 pm

      Thanks for your question! It has now been answered at the following link: https://simpleandpractical.com/lamotrigine-psychiatric-side-effects/

      Reply
  2. Anoop G says

    September 26, 2019 at 12:40 pm

    The textbook “Synopsis of Psychiatry” mentions other indications of lamotrigine such as borderline personality disorder and also in pain syndromes. How far has it has been found to be useful for the same, especially Borderline PD?
    Also the book says it is not recommended below 16years. Do we strictly follow such cut-offs in guidelines while using lamotrigine?

    Reply

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