Accentuation des crises tonico-cloniques sous lamotrigine dans l’épilepsie myoclonique juvénile

Management of juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) is a common form of epilepsy and a fairly lifelong disorder that may significantly lower a patient's expectations and potential for a full life. Luckily, it is also a highly treatable disorder, and up to 85% of patients with JME will enjoy satisfactory seizure control. Among anticonvulsants, valproate still stands out as the most efficacious drug, but may be poorly tolerated by some, and is considered unsafe for the fetuses of pregnant women. Alternatives have emerged in recent years, especially levetiracetam, but also topiramate, zonisamide or lamotrigine. In some cases, combination therapy may be useful or even required. One should not forget the potential aggravation induced not only by some commonly used anticonvulsants, especially carbamazepine and oxcarbazepine, but also, in some patients, by lamotrigine. In special settings, older drugs like benzodiazepines and barbiturates may be useful. But the management of JME should also include intervention in lifestyle, with strict avoidance of sleep deprivation and the management of copathologies, including the cognitive and psychiatric problems that are often encountered. With adequate management, there will only remain a small proportion of patients with uncontrolled epilepsy and all of its related problems. Juvenile myoclonic epilepsy is a condition in which the clinician has a fair chance of significantly helping the patient with medication and counseling.

Adjunctive therapy for the treatment of primary generalized tonic-clonic seizures: focus on once-daily lamotrigine

Idiopathic generalized epilepsies are frequently encountered by neurologists, and providing an accurate diagnosis and effective treatment(s) are the necessary components of successful patient care. With the introduction of new antiepileptic medications, physicians are better equipped for this goal. The immediate-release formulation of lamotrigine (LTG-IR) has been approved for primary generalized tonic-clonic seizures since 2006. The extended-release formulation of lamotrigine (LTG-XR) was approved for adjunctive therapy in patients with primary generalized tonic-clonic seizures in 2010. Although its exact mechanism of action is not yet fully elucidated, studies have demonstrated multiple possible pathways. Although both the LTG-IR and LTG-XR formulations have similar side effects and are generally well tolerated, LTG-XR may be preferable for its ease of use, which may increase patient compliance and decrease fluctuations in serum drug levels. The ease of conversion between the formulations also makes lamotrigine an attractive treatment option for patients with primary generalized tonic-clonic seizures. LTG-IR has demonstrated efficacy in treatment-resistant idiopathic generalized epilepsies in both adults and children. Although there are still some questions regarding all possible applications of LTG-XR, as further research is being done, it is clear that LTG-XR may hold some advantages when compared with other anticonvulsants.

Photochemical reactions involved in the phototoxicity of the anticonvulsant and antidepressant drug lamotrigine (Lamictal)

Lamotrigine (LTG) [3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine], an anticonvulsant and antidepressant drug Lamictal, produces a (photo)toxic response in some patients. LTG absorbs UV light, generating singlet oxygen (1O2) with a quantum yield of 0.22 in CH2Cl2, 0.11 in MeCN and 0.01 in D2O. A small production of superoxide radical anion was also detected in acetonitrile. Thus, LTG is a moderate photosensitizer producing phototoxicity and oxidizing linoleic acid. LTG is a weak 1O2 quencher (k(q) = 3.2 x 10(5) M(-1) s(-1) in MeCN), but its photodecomposition products in dimethyl sulfoxide (DMSO) quenched 1O2 very efficiently. Upon intense UV irradiation from a xenon lamp, LTG was photobleached rapidly in DMSO and slowly in acetonitrile, alcohol and water. The rate increased significantly when laser pulses at 266 nm were employed. The photobleaching products generated 1O2 twice as strongly as LTG. Photobleaching was usually accompanied by the release of chloride anions, which increased in the presence of ascorbic acid. This suggests the formation of aryl radicals via dechlorination, a process which may be responsible for the photoallergic response observed in some patients. Our results demonstrate that LTG is a moderate generator of 1O2 prone to photodechlorination, especially in a reducing environment, which can contribute to the reported phototoxicity of LTG.