Lamotrigine is an antiepileptic drug (AED) and mood stabiliser that has become an important part of modern neurology and psychiatry. It is especially valued because it not only controls seizures but also helps prevent mood episodes in bipolar disorder. Lamotrigine belongs to the phenyltriazine class of compounds and has a distinctive mechanism compared with older anticonvulsants like carbamazepine or valproate. It works mainly by stabilising neuronal membranes and reducing excitatory neurotransmitter release, particularly glutamate and aspartate, through inhibition of voltage-sensitive sodium channels. These properties explain both its anticonvulsant and mood-stabilising benefits.
Lamotrigine was first approved in the 1990s for epilepsy but has since gained widespread use in bipolar disorder, particularly for the maintenance phase of bipolar I disorder where it reduces the risk of depressive relapses. Unlike lithium and many antipsychotics, lamotrigine is less effective for acute mania, but its strong preventive effects against bipolar depression have made it a preferred long-term therapy in many treatment guidelines. It is also considered to have a more favourable tolerability profile compared to older anticonvulsants.
Lamotrigine is available as standard tablets, dispersible tablets, chewable tablets, and extended-release formulations. This flexibility allows use in a wide range of patients, including children and those with swallowing difficulties. Dose titration must be carried out carefully and slowly, as rapid escalation increases the risk of serious skin reactions such as Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Despite these risks, with careful management, lamotrigine has become a cornerstone therapy for certain epilepsies and bipolar disorder.
The drug is usually well tolerated, with common side effects including headache, dizziness, and gastrointestinal upset. Importantly, it causes less weight gain, sedation, or cognitive dulling compared with other mood stabilisers or antiepileptics, which contributes to its popularity among clinicians and patients. Nonetheless, the possibility of rare but severe dermatological reactions requires vigilance, particularly in the first eight weeks of therapy.
Lamotrigine’s place in therapy continues to expand, with ongoing studies examining its role in unipolar depression, anxiety disorders, neuropathic pain, and other off-label conditions. It remains under specialist supervision for most indications, but general practitioners may also be involved in long-term monitoring once stabilisation is achieved.
Patients must be counselled about the importance of adherence and not stopping the medication suddenly, as abrupt withdrawal can precipitate seizures or relapse of mood symptoms. Regular monitoring and follow-up are key parts of therapy.
Compared with many other mood stabilisers, lamotrigine is less likely to cause sedation, weight gain, or metabolic changes. However, vigilance for dermatological and psychiatric adverse effects is crucial.
Close clinical follow-up is necessary in the early months of therapy. Patients and carers must be educated about warning signs and emergency protocols.
Patients should be advised to inform their doctor about all prescription and over-the-counter medicines, as well as herbal remedies like St John’s wort, which may alter metabolism.
Overdose: Symptoms may include ataxia, nystagmus, loss of consciousness, seizures, coma, and cardiac arrhythmias. Treatment is supportive, with hospital admission often required. Activated charcoal may be considered if ingestion was recent.
Accidental double dose: May cause dizziness, unsteadiness, nausea, or mild sedation. Patients should monitor for symptoms and seek medical advice if they feel unwell.
Missed dose: If remembered within a few hours, take it. If close to the next dose, skip and resume the regular schedule. Do not double up. Consistency is important to prevent seizure recurrence or mood instability.
Patients should always carry medication information and an emergency contact card in case of overdose situations.
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