Lamotrigine

Seizure Control

Lamotrigine is an anticonvulsant used to treat various forms of epilepsy in both adults and children. It may be prescribed alone or alongside other medications to manage:

• Partial-onset seizures
• Primary generalized tonic-clonic seizures
• Seizures associated with Lennox-Gastaut syndrome

Bipolar Disorder

This medication is also used as a maintenance treatment for adults with bipolar I disorder. Its primary goal in this context is to delay the occurrence of mood episodes, including:

• Depression
• Mania
• Hypomania
• Mixed episodes

Lamotrigine is intended to help stabilize mood over the long term rather than treating acute, sudden mood changes.

Mechanism of Action

Lamotrigine belongs to a class of drugs known as antiepileptics or anticonvulsants. While the exact way it works is not completely understood, researchers believe it helps stabilize the electrical activity of nerve cells in the brain.

Stabilizing Nerve Signals

The medication works primarily by blocking voltage-sensitive sodium channels in the brain. By doing this, it helps prevent nerve cells from sending repetitive or excessive electrical signals. This stabilization helps to:

• Reduce Seizures: By preventing overactive electrical bursts, it helps control various types of seizures.
• Balance Neurotransmitters: It inhibits the release of certain chemicals, such as glutamate, which are responsible for exciting nerve cells.

Effect on Mood

In the treatment of bipolar disorder, lamotrigine is thought to help delay or prevent mood episodes, such as depression or mania. Although the precise mechanism for mood stabilization is not fully established, it is believed to involve the same stabilization of nerve activity and chemical balance in the brain.

Common Side Effects

Many people using lamotrigine experience mild side effects. These may include:

• Dizziness or loss of coordination
• Headache
• Blurred or double vision
• Nausea, vomiting, or stomach pain
• Drowsiness or fatigue
• Trouble sleeping
• Dry mouth
• Tremors or shaking
• Back pain
• Sore throat or runny nose

Serious Side Effects

Some side effects can be severe. Contact a healthcare provider immediately if you notice:

• A skin rash, hives, or blisters, which may be signs of a life-threatening reaction.
• Swollen lymph nodes, fever, or painful sores in the mouth or around the eyes.
• New or worsening depression, anxiety, or thoughts about suicide or self-harm.
• Signs of meningitis, such as a stiff neck, fever, headache, and sensitivity to light.
• Unusual bruising, bleeding, or pale skin.
• Severe muscle pain or weakness.
• Yellowing of the skin or the whites of the eyes.
• Chest pain or shortness of breath.

Serious Skin Rashes

Lamotrigine can cause serious, life-threatening rashes, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). These reactions usually occur within the first 2 to 8 weeks of treatment. The risk is higher in children, people taking valproate, or when the starting dose is too high or increased too quickly. Any rash should be reported to a healthcare provider immediately, as it is impossible to predict if a mild rash will become serious.

Immune System Reaction (HLH)

A rare but very serious immune system reaction called hemophagocytic lymphohistiocytosis (HLH) has been reported. This condition causes severe inflammation throughout the body. Symptoms may include a high fever, skin rash, enlarged liver or spleen, yellowing of the skin or eyes, and unusual bleeding.

Heart Rhythm Problems

Studies have shown that lamotrigine may increase the risk of serious heart rhythm problems (arrhythmias) in people who already have certain heart conditions or heart disease. This risk is due to the way the medication affects the electrical signals in the heart. Healthcare providers typically evaluate heart health before starting this medication in patients at risk.

Suicidal Thoughts and Behavior

Like other antiepileptic drugs, lamotrigine may increase the risk of suicidal thoughts or actions in a small number of people. Changes in mood, worsening depression, or unusual changes in behavior should be monitored closely by caregivers and healthcare providers.

Aseptic Meningitis

Lamotrigine may cause aseptic meningitis, which is an inflammation of the protective membrane covering the brain and spinal cord. Symptoms include headache, fever, nausea, vomiting, stiff neck, and sensitivity to light. These symptoms typically occur within 1 to 45 days after starting the medication.

Withdrawal and Seizure Risk

Stopping lamotrigine suddenly can cause an increase in seizure frequency. If the medication needs to be discontinued, it is typically done gradually over at least two weeks unless a serious reaction, such as a rash, requires immediate cessation.

Pregnancy and Oral Contraceptives

Hormonal contraceptives can interact with lamotrigine, potentially requiring dosage adjustments. Additionally, lamotrigine levels may decrease significantly during pregnancy, which may affect seizure control or mood stability.

Pregnancy

Deciding whether to continue lamotrigine during pregnancy involves weighing the benefits of controlling seizures or mood symptoms against potential risks to the fetus. Untreated epilepsy or bipolar disorder can pose significant health risks to both the pregnant person and the developing baby. You should not start or stop taking this medication during pregnancy without consulting a healthcare provider.

During pregnancy, the body's metabolism changes, which often causes the level of lamotrigine in the blood to decrease. Healthcare providers typically monitor blood levels closely throughout pregnancy and may need to increase the dosage to ensure the medication remains effective. After delivery, the dose may need to be adjusted again as the body returns to its pre-pregnancy state.

While some data have investigated a potential link between lamotrigine and birth defects like oral clefts, the evidence is not conclusive. To help monitor the safety of the medication, patients are encouraged to enroll in the North American Antiepileptic Drug Pregnancy Registry.

Breastfeeding

Lamotrigine passes into breast milk, and nursing infants can be exposed to the medication. While many people continue to take lamotrigine while breastfeeding, it is important to monitor the infant closely for potential side effects. Contact a healthcare provider immediately if a breastfed infant develops any of the following:

• A skin rash
• Extreme sleepiness or lethargy
• Poor sucking or difficulty feeding
• Difficulty breathing

A healthcare provider can help determine the best feeding plan based on your specific medical needs and the health of the infant.

Available Forms

Lamotrigine is provided in the following oral forms:

• Immediate-release tablets: Standard tablets intended to be swallowed whole.
• Chewable dispersible tablets: These may be swallowed whole, chewed, or mixed into a small amount of liquid such as water or fruit juice.
• Extended-release tablets: These are formulated to release the medication slowly into the body. They must be swallowed whole and should not be crushed, chewed, or broken.
• Orally disintegrating tablets: These tablets are designed to dissolve quickly on the tongue and can be swallowed with or without water.

FDA Approval and Indications

The U.S. Food and Drug Administration (FDA) has approved lamotrigine for the treatment of epilepsy and bipolar I disorder. It is indicated for use in adults and children for various types of seizures and as a maintenance treatment to delay mood episodes in adults with bipolar disorder.

Boxed Warning

Lamotrigine carries a boxed warning for serious and potentially life-threatening skin rashes, including Stevens-Johnson syndrome and toxic epidermal necrolysis. The risk of these reactions is higher in pediatric patients, those taking valproate concurrently, or when the starting dose or dose escalation exceeds recommended levels.

Safety Communications

The FDA has issued several safety alerts regarding lamotrigine:

• Heart Rhythm Problems: Studies indicate an increased risk of heart rhythm problems (arrhythmias) in patients with pre-existing heart disease or certain underlying cardiac conditions.
• Immune System Reaction: The FDA warned of a rare but serious immune system reaction called hemophagocytic lymphohistiocytosis (HLH), which can cause severe inflammation and lead to hospitalization or death.
• Aseptic Meningitis: There is a risk of aseptic meningitis, a non-bacterial inflammation of the membranes covering the brain and spinal cord.

Risks of Abrupt Discontinuation

You should not stop taking lamotrigine without first consulting your doctor, even if you feel well. Stopping the medication suddenly can cause severe health issues, particularly for those being treated for epilepsy. Risks include:

• Increased Seizures: Abruptly ending treatment can cause seizures to return or occur more frequently.
• Status Epilepticus: In some cases, sudden withdrawal can lead to prolonged seizures that do not stop, which is a medical emergency.
• Return of Symptoms: For those taking lamotrigine for bipolar disorder, stopping the medication may lead to a recurrence of mood symptoms.

The Tapering Process

To safely discontinue lamotrigine, healthcare providers typically recommend a gradual reduction in dosage. This tapering process usually occurs over a period of at least two weeks, though your doctor may suggest a longer timeframe based on your specific medical history and current dosage.

Restarting Treatment

If you stop taking lamotrigine for more than a few days, you should not restart it at your previous dose. Contact your healthcare provider immediately for instructions. Because of the risk of developing a serious and potentially life-threatening skin rash, you will likely need to restart the medication at a very low dose and gradually increase it again, following the initial titration schedule.