Lamotrigine belongs to a class of medications known as antiepileptics. It is used alone or in combination with other medications to manage seizures associated with epilepsy when other medications have not been effective or have been stopped. It is also used along with other medications to manage seizures associated with Lennox-Gastaut syndrome. Lamotrigine works by decreasing the chemicals in the brain that are believed to contribute to seizures.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended dose of lamotrigine varies according to a person's need and the other antiepileptic medications they are taking. When used to treat adults, lamotrigine is started at a low dose, ranging from 25 mg every other day to 50 mg once a day. Over a number of weeks, the dose is gradually increased until a maintenance dose is reached. The maintenance dose ranges from 50 mg to 250 mg twice a day. For children, lamotrigine is given according to the weight of the child. It should not be used for children who weigh less than 9 kg.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

The regular tablets must be swallowed whole and not chewed or crushed. The chewable tablets may be swallowed whole, chewed, or dissolved in a teaspoonful of water or fruit juice. The tablets take about 1 minute to dissolve. Once dissolved, swirl the solution and drink the entire amount immediately. Add some water to the glass and drink that as well to make sure there is no medicine left in the glass.

Lamotrigine may be taken with or without food.

It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If your next dose is less than 4 hours away, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice. If you miss more than a few days of lamotrigine doses, talk to your doctor before restarting the medication. You may need to start taking the medication at a lower dose than you were taking previously.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

25 mg
Each white to off-white, shield-shaped, uncoated tablet debossed with "LG 25" on one side and "J and P" on either side of the scoreline on the other side, contains 25 mg of lamotrigine. Nonmedicinal ingredients: colloidal anhydrous silica, lactose monohydrate, magnesium stearate, microcrystalline cellulose, povidone K-30, sodium starch glycolate, and talc.

100 mg
Each peach-coloured, shield-shaped, uncoated tablet debossed with "LG 100" on one side and "J and P" on either side of the scoreline on the other side, contains 100 mg of lamotrigine. Nonmedicinal ingredients: colloidal anhydrous silica, lactose monohydrate, magnesium stearate, microcrystalline cellulose, povidone K-30, sodium starch glycolate, talc, and FD&C Yellow No. 6 Aluminum Lake.

150 mg
Each cream-coloured, shield-shaped, uncoated tablet, debossed with "LG 150" on one side and "J and P" on either side of the scoreline on the other side, contains 150 mg of lamotrigine. Nonmedicinal ingredients: colloidal anhydrous silica, lactose monohydrate, magnesium stearate, microcrystalline cellulose, povidone K-30, sodium starch glycolate, talc, and iron oxide yellow.

Do not take this medication if you are allergic to lamotrigine or any ingredients of the medication.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• difficulty sleeping
• dizziness
• drowsiness
• fatigue
• headache
• nasal congestion
• nausea
• stomach upset
• vomiting
• weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• blurred vision or other changes in vision
• chest pain
• clumsiness or unsteadiness
• continuous, uncontrolled back-and-forth or rolling eye movements
• double vision
• flu-like symptoms (e.g., fever, chills, or sore throat)
• hallucinations (seeing or hearing things that aren't there)
• itchy eyes, with discharge
• mood or mental changes (e.g., agitation, anxiety, aggression, irritability, or nervousness)
• neck, joint, or abdominal pain
• nightmares
• signs of anemia (low red blood cells; e.g., pale skin, unusual tiredness or weakness)
• signs of kidney problems (e.g., pain in the lower back, pain with urination)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• skin rash
• swollen glands in the armpit, neck, or groin, or facial swelling
• tremor
• uncontrollable muscle movements involving the face, eyes, neck, trunk, arms, or legs

Stop taking the medication and seek immediate medical attention if any of the following occur:

• increase in seizures
• signs of an allergic reaction (such as difficulty breathing; hives; or swelling of the face, tongue, or throat)
• signs of bleeding (such as easy bruising, bleeding gums, nosebleeds, vomiting blood, blood in the urine, dark tarry stools)
• signs of meningitis not caused by infection (e.g., headache [severe], throbbing, or with stiff neck or back)
• signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
• symptoms of haemophagocytic lymphohistiocytosis (HLH) (e.g., high body temperature, skin rashes, difficulty walking, abdominal swelling or tenderness, vision changes and seizures)
• symptoms of muscle damage (unexplained muscle pain, tenderness, or weakness; or brown or discoloured urine – especially if you also have a fever or a general feeling of being unwell)
• thoughts of suicide or harming yourself

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should take this medication.

Aseptic meningitis: Rarely, lamotrigine can cause symptoms of aseptic meningitis (inflammation or swelling of the membranes around the brain and spinal cord that is not caused by bacteria). If you have an autoimmune condition (e.g., systemic lupus erythematosus, mixed connective tissue disease), you are more at risk for developing this. If you experience symptoms such as stiff neck, severe headache, nausea, vomiting, fever, or changes in consciousness, stop taking this medication and get immediate medical attention.

Birth control pills/hormone replacement therapy: The dose of lamotrigine you take may need to be adjusted if you start or stop oral contraceptives or other female hormonal treatments, such as hormone replacement therapy.

According to some case reports, when lamotrigine was taken in combination with birth control pills or other hormone replacement, rarely seizures, unexpected pregnancies, and menstrual bleeding disorders (e.g., breakthrough bleeding) occurred.

Do not start or stop taking these medications without consulting your doctor. If you experience changes in your menstrual pattern such as breakthrough bleeding while taking lamotrigine with these medications, contact your doctor.

Blood counts: This medication can decrease the number of neutrophils (a type of white blood cell that helps fight infection), red blood cells (which carry oxygen), and platelets (which help your blood to clot). Your doctor will do blood tests to monitor this. If you notice any signs of infection (e.g., fever, chills, or sore throat) or unusual bleeding or bruising, contact your doctor immediately.

Drowsiness/reduced alertness: If you have uncontrolled epilepsy, you should not drive or handle potentially dangerous machinery. Common side effects of lamotrigine include dizziness, problems with muscle coordination, drowsiness, double vision, and blurred vision. You should not undertake activities requiring mental alertness or physical coordination until you determine how lamotrigine affects you.

Heart disease: Lamotrigine can cause a change in the rhythm of the heart, particularly for people who already have certain heart conditions. If you have any heart condition, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Haemophagocytic lymphohistiocytosis (HLH): Lamotrigine has rarely been associated with HLH, a condition caused by an overactive immune system. If HLH is not identified and treated quickly, it can be fatal. If you experience fever, skin rashes, trouble walking or seeing, swelling or tenderness in the stomach, nausea, vomiting, difficulty breathing, or swollen lymph nodes, get medical attention as soon as possible.

Hypersensitivity reaction: Lamotrigine has occasionally caused a severe allergic reaction called hypersensitivity syndrome. This reaction involves a number of organs in the body and may be fatal if not treated quickly. Stop taking the medication and get immediate medical attention if you have symptoms of a severe allergic reaction, including fever, swollen glands, yellowing of the skin or eyes, or flu-like symptoms with skin rash or blistering.

Kidney function: Kidney disease or reduced kidney function may cause this medication to build up in the body, causing side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. If you have reduced liver function or liver disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

This medication may also cause a decrease in liver function. If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Rashes: Severe skin rashes leading to hospitalization have been reported by people taking lamotrigine. This appears more likely to happen if the dose is increased too quickly. The risk of a serious rash is higher for children and may be higher for people who have experienced rashes when taking other medication for epilepsy. Nearly all cases of serious rashes associated with lamotrigine have occurred within 2 to 8 weeks of the start of treatment. If you notice a skin rash, fever, or swollen glands, seek medical attention immediately.

Stopping the medication: Suddenly stopping any antiepileptic medication may cause rebound seizures. In general, the medication should be stopped gradually, as directed by your doctor, to minimize this risk. Before stopping lamotrigine, contact your doctor for guidance.

Suicidal or agitated behaviour: People with epilepsy sometimes experience depression. If you have depression or bipolar disorder, you may be at an increased risk of feeling agitated (restless, anxious, aggressive, emotional, and feeling not like themselves), or wanting to hurt yourself or others. If you experience these side effects or notice them in a family member who is taking this medication, contact your doctor immediately.

Pregnancy: The use of lamotrigine during pregnancy has been associated with an increased number of cases of cleft palate, a birth defect. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Do not stop taking the medication until you've consulted your doctor, since doing so can cause rebound seizures that may be harmful to the mother and unborn baby.

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and taking lamotrigine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding. Generally, breast-feeding while taking lamotrigine is not recommended.

Children: The safety and effectiveness of using lamotrigine for children under 16 years of age, other than those with Lennox-Gastaut syndrome, have not been established. Lamotrigine should not be used for children who weigh less than 9 kg.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.