Lacosamide

Seizure Management

Lacosamide is used to treat epilepsy by controlling abnormal electrical activity in the brain. Its primary uses include:

• Partial-onset seizures: It is approved for use either alone or with other medications to treat partial-onset seizures in adults and children as young as 1 month old.
• Primary generalized tonic-clonic seizures: It is used as an adjunctive (add-on) therapy with other seizure medicines to treat primary generalized tonic-clonic seizures in adults and children 4 years of age and older.

Lacosamide is available in multiple forms, including tablets, an oral solution, and an injection. The injection form is typically used in a clinical setting when the medication cannot be taken by mouth.

Mechanism of Action

Lacosamide belongs to a group of medicines called anticonvulsants or anti-epileptic drugs. It works by decreasing abnormal electrical activity in the brain to help prevent and control seizures.

Stabilizing Brain Activity

The exact way lacosamide works in humans is not completely understood. However, research suggests it affects the way brain cells communicate through electrical signals. It is believed to work by:

• Targeting sodium channels: Brain cells use sodium channels to send electrical impulses. Lacosamide is thought to selectively enhance the slow inactivation of these channels.
• Reducing hyperexcitability: By affecting these channels, the medication helps stabilize nerve cells that are overactive.
• Inhibiting repetitive firing: This stabilization prevents the brain from sending out the rapid, repetitive electrical signals that cause a seizure to occur.

By managing these electrical pulses, lacosamide helps reduce the number and severity of partial-onset seizures.

Common Side Effects

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

• Dizziness or a spinning sensation
• Headache
• Nausea or vomiting
• Double or blurred vision
• Diarrhea
• Feeling tired or weak
• Problems with balance or coordination
• Itching

Serious Side Effects

Contact a healthcare provider immediately if you experience any of the following serious symptoms:

• Heart rhythm changes: Fast, slow, or pounding heartbeat, chest pain, shortness of breath, or feeling lightheaded as if you might pass out.
• Mood or behavior changes: New or worsening depression, anxiety, irritability, agitation, or thoughts about self-harm or suicide.
• Allergic reactions: Severe skin rash, hives, fever, swollen glands, or swelling of the face, lips, or tongue.
• Liver problems: Yellowing of the skin or eyes (jaundice), dark urine, or pain in the upper right side of the stomach.

Lacosamide can cause significant dizziness and coordination issues, which may increase the risk of accidental falls.

Suicidal Thoughts and Behavior

Antiepileptic drugs, including lacosamide, may increase the risk of suicidal thoughts or behaviors. It is important to monitor for any new or worsening symptoms of depression, unusual changes in mood, or suicidal ideation.

Heart Rhythm Effects

Lacosamide can affect the heart's electrical activity, specifically by prolonging the PR interval. This can lead to fainting (syncope) or abnormal heart rhythms like atrial fibrillation or flutter. Risk is higher for individuals with existing heart conditions, such as:

• Heart block or sick sinus syndrome.
• Severe heart disease or heart failure.
• Concurrent use of other medications that affect heart conduction.

Dizziness and Coordination

This medication frequently causes dizziness, double vision, and difficulty with coordination or balance. These side effects can impair the ability to perform tasks requiring alertness and may increase the risk of falls.

Serious Allergic Reactions

A serious, potentially life-threatening condition known as Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) has been reported. This reaction can affect multiple organs and may present with fever, rash, or swollen lymph nodes.

Withdrawal Seizures

Stopping lacosamide abruptly can lead to an increase in seizure frequency or severe, continuous seizures. The dose is typically reduced gradually under medical supervision.

Phenylketonuria Warning

Some liquid forms of lacosamide contain aspartame, which is a source of phenylalanine. This is a concern for individuals with phenylketonuria (PKU).

Pregnancy

There is limited research on the effects of lacosamide in pregnant women. In animal studies, the drug was associated with developmental issues when administered at high doses. Because human data is insufficient, healthcare providers generally only prescribe lacosamide during pregnancy if the potential benefits to the mother outweigh the potential risks to the fetus.

Maintaining seizure control is critical during pregnancy, as seizures can harm both the mother and the baby. Patients are encouraged to discuss their treatment plan with their healthcare provider if they become pregnant or plan to become pregnant. There is also a North American Antiepileptic Drug (NAAED) Pregnancy Registry that monitors outcomes for women taking seizure medications.

Breastfeeding

It is currently unknown whether lacosamide is present in human breast milk. Animal studies have shown that the medication is excreted in milk, which suggests a possibility that it could pass to a nursing infant. Decisions regarding breastfeeding while taking lacosamide should be made in consultation with a healthcare professional, considering the importance of the drug to the mother and the potential risks to the infant.

Available Forms

Lacosamide is produced in the following forms:

• Oral Tablets: These are solid tablets taken by mouth.
• Oral Solution: This is a liquid version of the medication taken by mouth, which may be used for patients who have difficulty swallowing tablets.
• Intravenous Injection: This is a sterile solution administered by a healthcare professional into a vein. It is generally used in clinical settings when oral administration is not feasible.

FDA Approval and Indications

The U.S. Food and Drug Administration (FDA) has approved lacosamide for the following uses:

• Treatment of partial-onset seizures in patients 1 month of age and older.
• Adjunctive therapy (used in combination with other medications) for primary generalized tonic-clonic seizures in patients 4 years of age and older.

Controlled Substance Status

Lacosamide is classified by the Drug Enforcement Administration (DEA) as a Schedule V controlled substance. This classification is used for drugs with a lower potential for abuse relative to other controlled substances, but it indicates that the medication still carries a risk of misuse that could lead to limited physical or psychological dependence.

Safety Warnings and Regulatory Oversight

While lacosamide does not have a boxed warning, the FDA requires several important safety warnings in its labeling:

• Suicidal Behavior and Ideation: Like other antiepileptic drugs, lacosamide may increase the risk of suicidal thoughts or behaviors. The FDA recommends that patients be monitored for any new or worsening signs of depression or unusual changes in mood.
• Cardiac Risks: Regulatory labeling includes warnings about PR interval prolongation, a change in the heart's electrical activity. This can increase the risk of serious heart rhythm issues, particularly in patients with pre-existing heart conditions or those taking other medications that affect heart rhythm.
• Serious Reactions: The FDA warns of rare but serious systemic reactions, such as Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), which can affect multiple organs and may be life-threatening.
• Dizziness and Ataxia: Labeling includes warnings regarding the potential for significant dizziness and coordination problems, which may increase the risk of accidental injury.

It is important not to stop taking lacosamide without first consulting a healthcare professional. Abruptly discontinuing this medication can cause seizures to return or occur more often than before. In some cases, stopping the drug suddenly may lead to serious, long-lasting seizures that require emergency medical attention.

To reduce the risk of withdrawal symptoms or increased seizure activity, doctors typically recommend a gradual reduction in dosage. This tapering process usually occurs over a period of at least one week, depending on the individual's medical history and current dosage level.

If you experience any of the following while reducing your dose or after stopping the medication, contact your doctor immediately:

• Increased frequency of seizures
• New types of seizures
• Worsening of your condition

Always ensure you have an adequate supply of the medication to avoid missing doses, as even a brief interruption can increase the risk of breakthrough seizures.