Loading...
Loading...
Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Lamotrigine
Generic Name
Lamotrigine
Active Ingredient
LamotrigineCategory
Anti-epileptic Agent [EPC]
Variants
226
References used for this content
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Lamotrigine, you must consult a qualified healthcare professional.
| 250 mg/1 | TABLET | ORAL | 65841-687 |
| 25 mg/1 | TABLET | ORAL | 65862-227 |
| 150 mg/1 | TABLET | ORAL | 65862-229 |
| 100 mg/1 | TABLET | ORAL | 68071-3944 |
| 100 mg/1 | TABLET | ORAL | 68788-7223 |
| 50 mg/1 | TABLET | ORAL | 69918-360 |
| 100 mg/1 | TABLET | ORAL | 70518-2343 |
| 25 mg/1 | TABLET | ORAL | 82009-131 |
| 300 mg/1 | TABLET, FILM COATED, EXTENDED RELEASE | ORAL | 10370-256 |
+ 38 more variants
Detailed information about Lamotrigine
Lamotrigine is a phenyltriazine-class anti-epileptic agent and mood stabilizer used to treat various types of seizures and delay the recurrence of mood episodes in patients with Bipolar I Disorder. It works by stabilizing neuronal membranes via sodium channel inhibition.
Dosage for lamotrigine is highly individualized and depends strictly on whether the patient is taking concurrent medications that affect its metabolism. A "slow and low" titration (gradual increase) is mandatory to minimize the risk of serious skin rashes.
Lamotrigine is approved for children as young as 2 years for certain types of epilepsy. Dosing is strictly weight-based (mg/kg). For example, in children taking valproate, the starting dose may be as low as 0.15 mg/kg/day. Pediatric patients must be monitored closely by a specialist, as the risk of rash is statistically higher in children than in adults.
In patients with significant renal impairment (reduced kidney function), the initial dose of lamotrigine may not need adjustment, but the maintenance dose should generally be reduced. Because lamotrigine and its metabolites are cleared by the kidneys, reduced clearance can lead to drug accumulation. Healthcare providers typically reduce the maintenance dose by 25% to 50% in cases of moderate to severe renal failure.
For patients with moderate hepatic impairment (Child-Pugh Grade B), doses should be reduced by approximately 25%. In severe hepatic impairment (Child-Pugh Grade C), the dose should be reduced by 50%. The liver is the primary site of glucuronidation, so impaired liver function directly increases the circulating levels of the drug.
While no specific age-based dosage adjustment is universally required, clinicians often start at the lower end of the dosing range for elderly patients. This population is more susceptible to balance issues (ataxia) and cognitive side effects, and they often have age-related declines in renal or hepatic function.
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and return to your regular schedule. Never take two doses at once to make up for a missed one. If you miss more than a few days of lamotrigine, do not restart at your previous dose. You must contact your doctor immediately, as you may need to restart the titration process from the lowest dose to avoid the risk of a serious rash.
Signs of a lamotrigine overdose may include ataxia (lack of muscle coordination), nystagmus (involuntary eye movement), increased seizures, coma, or heart rhythm abnormalities (intraventricular conduction delay). In the event of a suspected overdose, contact emergency services or a poison control center immediately. Emergency treatment usually involves supportive care and gastric lavage if the ingestion was recent.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop the medication without medical guidance, as sudden discontinuation can trigger seizures.
Most patients tolerate lamotrigine well, but common side effects can occur, particularly during the titration phase. These usually diminish as the body adjusts to the medication:
Lamotrigine is a high-alert medication because of the potential for severe dermatological and immunological reactions. Patients must be educated on the "titration schedule"—the process of slowly increasing the dose. Skipping doses or restarting at a high dose after a break can be fatal due to the risk of Stevens-Johnson Syndrome.
FDA Black Box Warning Summary: Lamotrigine can cause serious, life-threatening rashes, including Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN). These rashes usually require hospitalization and discontinuation of the drug. The risk is highest in children and in those taking valproate or exceeding the recommended titration schedule. While benign rashes also occur, it is impossible to predict which rashes will become life-threatening. Therefore, the drug should ordinarily be discontinued at the first sign of a rash unless the rash is clearly not drug-related.
There are few absolute contraindications for lamotrigine combinations, but use with other drugs that cause severe QT prolongation or those that have a high cross-sensitivity for SJS (like certain other AEDs) requires extreme caution. The most critical "do not use" scenario is restarting lamotrigine at a high dose after a treatment gap without a new titration.
Lamotrigine must NEVER be used in the following circumstances:
These are conditions where the benefit must clearly outweigh the risk, and intensive monitoring is required:
Lamotrigine is often considered one of the safer anti-epileptic drugs during pregnancy, but it is not without risks. It is classified as Pregnancy Category C (under the old system).
Lamotrigine passes into breast milk in significant amounts. The milk-to-plasma ratio is approximately 0.6. While many infants do not show adverse effects, there is a risk of the infant developing a rash or experiencing breathing problems (apnea). If breastfeeding, the infant must be monitored closely for any skin changes, drowsiness, or poor feeding. The decision to breastfeed should be a shared decision between the mother, neurologist, and pediatrician.
Lamotrigine's primary mechanism is the inhibition of voltage-gated sodium channels. It binds specifically to the inactive state of the channel, which prevents the rapid, repetitive firing of action potentials in neurons. This action is "use-dependent," meaning it targets overactive neurons while sparing normal neuronal activity. Additionally, lamotrigine inhibits the presynaptic release of glutamate, the brain's main excitatory neurotransmitter. By reducing glutamate-mediated excitability, it prevents the initiation and spread of seizure activity and stabilizes the mood fluctuations seen in Bipolar I Disorder.
Lamotrigine shows a clear dose-response relationship for both its therapeutic effects and its side effects. The onset of action for epilepsy can be seen within 1-2 weeks of reaching a therapeutic dose, but for Bipolar Disorder, the full prophylactic effect may not be evident for several weeks or months. Tolerance to the anticonvulsant effects is rarely reported, making it suitable for long-term maintenance therapy.
| Parameter | Value |
|---|---|
Common questions about Lamotrigine
Lamotrigine is primarily used to treat certain types of epilepsy and to manage Bipolar I Disorder. In epilepsy, it is effective for partial-onset seizures, primary generalized tonic-clonic seizures, and seizures associated with Lennox-Gastaut syndrome in both adults and children. For Bipolar I Disorder, it is used as a maintenance treatment to increase the time between mood episodes, such as depression or mania. It is particularly valued in psychiatry for its ability to prevent bipolar depression without causing significant weight gain. Always consult your doctor to see if lamotrigine is appropriate for your specific diagnosis.
The most frequently reported side effects of lamotrigine include dizziness, headache, double vision, and nausea. Some patients also experience sleepiness, lack of coordination (ataxia), or a mild skin rash. Most of these side effects are dose-related and often occur during the initial titration phase when the dose is being increased. While many side effects are mild and temporary, any rash must be reported to a healthcare provider immediately. Your doctor will monitor you closely during the first few months of treatment to ensure these effects remain manageable.
It is generally recommended to avoid or strictly limit alcohol consumption while taking lamotrigine. Alcohol is a central nervous system depressant that can worsen the side effects of lamotrigine, such as dizziness, drowsiness, and impaired concentration. Combining the two can significantly increase the risk of accidental injury or falls. Furthermore, alcohol can disrupt sleep patterns and mood stability, which may counteract the benefits of the medication for bipolar disorder. Discuss your alcohol intake habits with your healthcare provider before starting this medication.
Lamotrigine is often considered one of the preferred anti-epileptic options during pregnancy because it has a lower risk of causing major birth defects compared to other drugs like valproate. However, it is not entirely risk-free, and pregnancy significantly changes how the body processes the drug. Blood levels of lamotrigine can drop by half during pregnancy, potentially leading to dangerous breakthrough seizures. If you are pregnant or planning to become pregnant, your doctor will likely need to adjust your dose and monitor your blood levels frequently. It is essential to join a pregnancy registry to help researchers continue to track the safety of this drug.
The time it takes for lamotrigine to work depends on the condition being treated and the necessary slow titration schedule. For epilepsy, some improvement may be noted within the first few weeks, but it often takes 6 weeks or longer to reach a therapeutic maintenance dose. For Bipolar I Disorder, lamotrigine is a long-term maintenance medication rather than a quick fix for acute symptoms. It may take several months of consistent use to fully realize its benefits in preventing future mood episodes. Patience is required, as rushing the dosage increases the risk of serious side effects.
You should never stop taking lamotrigine suddenly unless specifically directed by your doctor due to a serious allergic reaction. For patients with epilepsy, abrupt discontinuation can trigger status epilepticus, a state of continuous, life-threatening seizures. For those with bipolar disorder, stopping the medication quickly can lead to a rapid relapse of depressive or manic symptoms. If you need to stop the medication, your healthcare provider will provide a tapering schedule to gradually reduce the dose over at least two weeks. Always follow medical advice regarding the discontinuation of any psychiatric or neurological medication.
If you miss a dose of lamotrigine, take it as soon as you remember, unless it is almost time for your next scheduled dose. In that case, skip the missed dose and continue with your regular schedule; never double the dose to catch up. If you miss more than three to five days of your medication, you must contact your doctor before taking another pill. Because the risk of a serious rash is linked to how quickly the drug is started, you may need to restart the low-dose titration process from the beginning. Consistency is vital for both safety and effectiveness.
Lamotrigine is generally considered to be 'weight-neutral,' meaning most patients do not experience significant weight gain or loss while taking it. This is a major advantage over other mood stabilizers and anti-epileptic drugs, such as valproate or lithium, which are frequently associated with metabolic changes and weight gain. In clinical trials, the incidence of weight gain was similar to that of patients taking a placebo. However, everyone's body reacts differently to medication. If you notice significant changes in your weight or appetite, you should discuss these concerns with your healthcare provider.
Lamotrigine can be taken with many other medications, but it has several critical drug interactions that require careful management. The most important interaction is with valproate, which significantly increases lamotrigine levels and the risk of a serious rash. Other drugs, like carbamazepine and certain birth control pills, can lower lamotrigine levels, making it less effective. Because of these complex interactions, it is essential to provide your doctor and pharmacist with a complete list of all prescription drugs, over-the-counter medicines, and herbal supplements you are using. Your dose may need to be adjusted whenever you start or stop another medication.
Yes, lamotrigine is widely available as a generic medication, which is typically much more affordable than the brand-name versions like Lamictal. Generic versions are required by the FDA to have the same active ingredient, strength, dosage form, and route of administration as the brand-name drug. While most patients switch between brand and generic versions without issue, some neurologists prefer that patients with epilepsy stay on the same manufacturer's version to ensure the most consistent blood levels. If you have concerns about switching between different versions of the medication, discuss them with your pharmacist or doctor.
Other drugs with the same active ingredient (Lamotrigine)
> Warning: Stop taking Lamotrigine and call your doctor immediately if you experience any of these.
With prolonged use, some patients may experience changes in bone mineral density, although this risk is lower with lamotrigine than with enzyme-inducing AEDs like phenytoin. Long-term cognitive effects are generally minimal, but patients should report any persistent memory or concentration issues to their provider.
Serious Skin Rashes: The FDA has issued a Black Box Warning for lamotrigine regarding serious, life-threatening rashes, including Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN).
Report any unusual symptoms, especially skin changes or fever, to your healthcare provider immediately.
Lamotrigine can cause dizziness, double vision, and lack of coordination. Patients should not drive or operate heavy machinery until they know how the medication affects them. In many jurisdictions, patients with epilepsy are legally restricted from driving until they have been seizure-free for a specific period (e.g., 6 to 12 months).
Alcohol can exacerbate the CNS depressant effects of lamotrigine, leading to increased dizziness and impaired motor skills. While not strictly contraindicated, patients are advised to limit or avoid alcohol consumption while taking this medication.
Never stop taking lamotrigine abruptly. Sudden withdrawal in patients with epilepsy can lead to status epilepticus (prolonged, life-threatening seizures). In patients with bipolar disorder, sudden stopping can cause a rapid return of mood symptoms. If the drug must be stopped, it should be tapered over at least two weeks unless a serious rash requires immediate cessation.
> Important: Discuss all your medical conditions, especially heart, liver, or kidney problems, with your healthcare provider before starting Lamotrigine.
Lamotrigine has been reported to interfere with some rapid urine drug screens, specifically leading to false-positive results for phencyclidine (PCP). If a drug screen is required, a more specific confirmatory test (such as GC/MS or LC/MS) should be requested.
For each major interaction, the mechanism usually involves the UGT1A4 enzyme pathway. Inhibition (by valproate) leads to toxicity risk, while induction (by carbamazepine or estrogen) leads to reduced efficacy. Management strategies always involve frequent blood level monitoring and precise dose titration.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, as even over-the-counter drugs can affect lamotrigine levels.
There is a known risk of cross-sensitivity between lamotrigine and other anticonvulsants. Approximately 25% to 30% of patients who have had a rash with carbamazepine or phenytoin may also develop a rash with lamotrigine. Healthcare providers must be informed of any previous adverse reactions to other anti-epileptic medications.
> Important: Your healthcare provider will evaluate your complete medical history, including cardiac and dermatological history, before prescribing Lamotrigine.
Lamotrigine is FDA-approved for adjunctive therapy for seizures in children aged 2 years and older. It is NOT approved for Bipolar Disorder in patients under 18. The risk of a serious, life-threatening rash is significantly higher in children than in adults. Healthcare providers must use the specific pediatric titration schedules and weigh the child frequently to ensure accurate dosing.
Clinical studies of lamotrigine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently than younger subjects. However, because elderly patients are more likely to have decreased hepatic, renal, or cardiac function and are often on multiple medications (polypharmacy), they should be started at the lowest possible dose. There is an increased risk of falls due to the side effects of dizziness and ataxia.
In patients with end-stage renal disease, the half-life of lamotrigine is prolonged. While the initial dose may follow standard protocols, the maintenance dose must be reduced. Lamotrigine is removed by hemodialysis; about 20% of the drug is cleared during a 4-hour dialysis session. Supplemental doses may be needed after dialysis.
Hepatic impairment reduces the glucuronidation of lamotrigine. For patients with Child-Pugh Grade B or C impairment, dose reductions of 25% to 50% are mandatory to prevent toxic accumulation of the drug.
> Important: Special populations require individualized medical assessment and more frequent blood level monitoring.
| Bioavailability | ~98% |
| Protein Binding | ~55% |
| Half-life (Monotherapy) | 25 - 33 hours |
| Half-life (with Valproate) | ~70 hours |
| Half-life (with Inducers) | ~14 hours |
| Tmax | 1.5 - 4.8 hours |
| Metabolism | Hepatic (UGT1A4 Glucuronidation) |
| Excretion | Renal (94%), Fecal (2%) |
Lamotrigine belongs to the Phenyltriazine class of anti-epileptic agents. It is often grouped with other "sodium channel blockers" like carbamazepine and oxcarbazepine, but its lack of CYP450 induction and its specific efficacy in bipolar depression distinguish it from these older medications.