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Key takeaways
The maximum lamotrigine dose for bipolar disorder is around 200 milligrams; however, some patients take upwards of 400 milligrams per day.
Lamotrigine is started at low doses and increased slowly to minimize serious side effects.
The dose of lamotrigine depends on several factors, including age, weight, patient response, medical conditions, potential drug interactions, and liver and kidney function.
To avoid adverse effects, it’s best to follow a titration schedule, avoid skipping or doubling doses, and keep the medication out of reach of young children.
Lamotrigine, sold under the brand names Lamictal and Subvenite, is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to treat epilepsy conditions, including tonic-clonic seizures and Lennox-Gastaut syndrome. Healthcare providers may also prescribe the anticonvulsant medicine to regulate the moods of people with bipolar I disorder. According to medical experts and supporting research, the maximum lamotrigine dose for bipolar disorder is typically 200 milligrams (mg) taken once daily, though doses may be exceeded in special circumstances.
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What is the starting dose of lamotrigine for bipolar disorder?
Sidd Arora, DO, MS, a triple board-certified physician in psychiatry, pain management, and addiction medicine, and the founder and medical director of The Care Clinic in Virginia, says the starting dose for lamotrigine for bipolar disorder is 25 mg once daily for the first two weeks. Over time, this dose slowly increases to a higher maintenance dose.
What is the maximum dose of lamotrigine for bipolar disorder?
For most of his adult patients, Dr. Arora prescribes a maximum daily dose of around 200 mg for the treatment of bipolar disorder. “The maximum dose can go up to 400 mg daily, but that really depends on the rest of the patient’s medication regimen,” he says. “For example, if someone is also taking Depakote, I have to cut the dose down to 100 mg a day because Depakote increases lamotrigine levels.” Depakote is a form of valproate (valproic acid), which is a mood stabilizer medication that is commonly prescribed to treat mania associated with bipolar disorder.
According to research, typical maintenance maximum doses for bipolar disorder are from 200 to 400 mg, with additional considerations when other medications are prescribed together with lamotrigine.
If prescribed lamotrigine, your healthcare provider will guide you through the process of titration, in which the dose is gradually increased over time to minimize the risk of severe side effects.
“If started too aggressively, lamotrigine can have severe side effects such as a severe skin rash,” says Ryan Sultan, MD, a double board-certified adult and child psychiatrist and the founder and medical director of Integrative Psychiatry in Chelsea, New York. “Like titration in other medicines, it allows the body to adapt and reach steady-state plasma concentrations without overshooting into toxicity or causing destabilization. Dosing is titrated until therapeutic benefit is achieved or limited by side effects.”
Some of the most common side effects of lamotrigine include:
- Dizziness
- Drowsiness
- Headache
- Double vision
- Loss of coordination
- Blurred vision
- Nausea
- Mild skin rash
- Sore throat
- Vomiting
- Nasal congestion
- Dry mouth
More serious side effects of the antiepileptic medication include:
- Seizures lasting longer than five minutes
- Withdrawal seizures (if the medication is stopped suddenly)
- Liver failure
- Irregular heartbeat
- Blood problems
- Kidney problems
- Aseptic meningitis
- Suicidal thoughts
- Severe or life-threatening hypersensitivity reactions, such as serious skin rash, Stevens-Johnson syndrome, angioedema, and toxic epidermal necrolysis
If you’re diagnosed with bipolar disorder or are switching medications, it’s crucial to follow your healthcare provider’s recommendations in appropriate dosing to ensure you get the most benefits with fewer unwanted side effects.
Factors that influence lamotrigine dosage
Several factors influence lamotrigine dosage, including:
Drug interactions
As mentioned, drugs like Depakote—which also treat bipolar disorder—can interact with lamotrigine and make the medication less effective or potentially increase the risk of mild to severe side effects.
“Drug interactions play a big role,” Dr. Arora says. “Valproate, as mentioned, increases lamotrigine levels, so the dose needs to be lower, while enzyme inducers like carbamazepine can lower its levels, which may require a higher dose.”
Here are a few known drug interactions for lamotrigine:
- Hormonal birth control pills: Ethinyl estradiol (estrogen) and levonorgestrel (synthetic progestogen)
- Antiseizure medications: Carbamazepine (Tegretol), phenytoin (Dilantin), primidone, phenobarbital, valproic acid (Depakene), and divalproex (Depakote)
- HIV medications: Lopinavir/ritonavir (Kaletra), atazanavir (Reyataz), and ritonavir (Norvir)
- Rifampin (Rifadin, Rimactane)
- Dofetilide (Tikosyn)
- Metformin
- Acetaminophen
Patient response
A patient’s response to the anticonvulsant medication also determines the dosage. “In the absence of valproate or inducers, patient response and symptom profile are what I use to assess dosages,” Dr. Sultan says. “Some may achieve remission at lower doses, while others require higher doses to see an effect.”
If a patient experiences side effects such as rashes, dizziness, headache, or nausea, Dr. Arora recommends reducing the titration process or making dose adjustments.
Age and body weight
There are also special considerations when treating adolescents with lamotrigine. “In pediatric patients, age and weight are especially important, since those factors directly influence how much medication they can safely and effectively process,” Dr. Arora says.
Dosage adjustments may be made for older adults, as these patients are more likely to have age-related liver, kidney, or heart problems that could make higher doses of lamotrigine unsafe.
Liver and kidney function
“Renal or liver impairment can also affect how the drug is metabolized, so I’ll adjust the dose accordingly,” Dr. Arora says. For patients with severe hepatic impairment, a healthcare provider may reduce the dose of lamotrigine by 25%, and further by 50% if ascites (fluid buildup in the abdomen) is present. For patients with renal impairment, the dose should be reduced by 25% if creatinine clearance levels (CrCl) are between 10 and 50.
“I like to remind my patients that psychiatric medicine is not fixed,” Dr. Sultan says. “Once you reach an appropriate target dose, it doesn’t have to be your set dose forever. Psychiatric medication dosages, especially, are constantly being evaluated. They are supposed to be in flux.”
Other medical conditions
The presence of any of the following medical conditions could impact the effectiveness and safety of taking lamotrigine for bipolar disorder:
- Blood or bone marrow problems
- Depression
- Heart disease (heart attack or heart failure)
- Heart rhythm problems
- Kidney disease
- Liver disease
- Pregnancy
Before being prescribed lamotrigine, please notify your healthcare provider of any medications you’re currently taking and which health conditions you have. Also, let them know if you may be pregnant or are planning a pregnancy. Talking with your provider about your health can help ensure the right dose of the drug and decrease the risk of interactions or side effects.
How to take lamotrigine
If your healthcare provider prescribes you lamotrigine to manage bipolar I disorder symptoms, here are some tips to consider while taking the medication to avoid unwanted side effects:
- Avoid skipping doses or doubling up: While mistakes happen, it’s best to avoid missed doses or doubling up on a dose to catch up. Dr. Arora explains that restarting lamotrigine at a high dose is risky, and there’s an increased risk of a rash developing.
- Follow the titration schedule and notify your healthcare provider of any side effects: You should avoid making dose adjustments without guidance from a medical professional. “Following the titration schedule exactly is critical for safety, and I tell patients to contact me right away if they notice any kind of rash, especially during the first two months when the risk is highest,” Dr. Arora says.
- Keep medication out of reach of children: If you’re the caregiver of a child taking lamotrigine, or are taking the medication yourself, Dr. Arora advises that you keep it away from a child’s reach and store it securely, as even a slight overdose can be very dangerous.
Aside from keeping the medication away from children, there are other considerations when caring for a child who’s on lamotrigine. “When I’m working with caregivers, I stress how important it is to stick closely to the weight-based titration schedule the prescriber provides; it’s not one-size-fits-all,” Dr. Arora explains.
If your child is taking lamotrigine, Dr. Sultan recommends keeping a log of their behavior and mood to gain a sense of ease and agency, and to be an active participant in their treatment. “Family members are often the first to notice behavioral changes and mood swings that could signal the onset or recurrence of bipolar disorder,” he says. “Early identification is integral to managing symptoms, and a family-oriented approach is extremely helpful in the management and treatment of the disorder.”
There are also special considerations depending on which formulation of lamotrigine you’re prescribed—extended release tablets, chewable tablets, or oral suspension. “The standard tablets need to be swallowed whole—they shouldn’t be crushed or chewed,” Dr. Arora says. “If someone has trouble swallowing, the chewable or dispersible tablets are a good alternative since they can be chewed or mixed into a small amount of liquid or soft food. There are also orally disintegrating tablets, or ODTs, which are designed to dissolve right in the mouth without any water.”
Lamotrigine can be taken with or without food, but it’s always best to follow your healthcare provider’s guidance in case they want you to take the antiepileptic drug in a certain way.
- Valproate (Depakote), National Alliance on Mental Illness (n.d.)
- Lamotrigine, StatPearls (2023)
- Lamotrigine, Mayo Clinic (2025)