Lamotrigine (lamotrigine)

The manufacturers state that lamotrigine should be used with caution in patients with severe renal impairment because there is insufficient information from controlled clinical studies to establish the safety and efficacy of the drug in such patients. The initial dosage of lamotrigine in patients with renal impairment should be based on the patient's existing anticonvulsant drug regimen. The manufacturers state that a reduced maintenance dosage of lamotrigine may be effective in patients with substantial renal impairment.

The manufacturers state that experience with lamotrigine therapy in patients with hepatic impairment is limited. Based on a clinical pharmacology study of the drug in a small number of patients with moderate to severe hepatic dysfunction, the manufacturers make the general recommendation that initial, escalation, and maintenance dosages of lamotrigine therapy should be decreased by approximately 25% in patients with moderate (e.g., Child-Pugh class B) or severe (e.g., Child-Pugh class C) hepatic impairment without ascites and by 50% in patients with severe hepatic impairment with ascites. Escalation and maintenance dosages should be adjusted according to clinical response. Dosage adjustment is not necessary in patients with mild (e.g., Child-Pugh class A) hepatic impairment.

Lamotrigine is administered orally as immediate-release formulations (conventional tablets, tablets for oral suspension, orally disintegrating tablets) or as extended-release tablets. Immediate-release formulations of the drug (Lamictal(R), generics) are administered once or twice daily; the extended-release tablets (Lamictal(R) XR) are administered once daily. Lamotrigine may be administered without regard to meals.

Lamotrigine conventional tablets should be swallowed whole.

Lamotrigine tablets for oral suspension may be swallowed whole, chewed (and consumed with a small amount of water or diluted fruit juice to aid swallowing), or dispersed in water or diluted fruit juice. To disperse the tablets, they should be added to a small volume (i.e., 5 mL or enough to cover the tablet) of liquid and allowed to disperse completely (over approximately 1 minute); the solution should then be swirled and consumed immediately. Administration of partial quantities of the dispersed tablets should not be attempted; calculated doses that do not correspond to available strengths of whole tablets should be rounded down to the nearest whole tablet.

Lamotrigine orally disintegrating tablets should be placed on the tongue and moved around in the mouth; the tablets should disintegrate rapidly in saliva, and then subsequently swallowed with or without water.

Lamotrigine extended-release tablets should be swallowed whole and not chewed, crushed, or divided.

Patients who are currently receiving or beginning therapy with lamotrigine and/or any other anticonvulsant for any indication should be closely monitored for the emergence or worsening of depression, suicidal thoughts or behavior (suicidality), and/or any unusual changes in mood or behavior. (See Suicidality Risk under Cautions.)

No dosing information is available for this tab.

No dosing information is available for this tab.

There is no enhanced messaging for this drug.

There are no contraindication interactions for this drug.

There are no severe interactions for this drug.

There are no moderate interactions for this drug.

Lamotrigine is contraindicated in patients with known hypersensitivity to the drug or any ingredient in the formulation.

There are no contraindication contraindications for this drug.

There are no severe contraindications for this drug.

There are no moderate contraindications for this drug.

There is no enhanced messaging for this drug.

There are no severe adverse reactions for this drug.

There are no less severe adverse reactions for this drug.

No enhanced messaging available.

No enhanced messaging available.

There are no adequate and well-controlled studies of lamotrigine in pregnant women. Women who are pregnant while receiving lamotrigine should be encouraged to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry at 888-233-2334 or http://www.aedpregnancyregistry.org/.

Data from several prospective pregnancy exposure registries and epidemiological studies of pregnant women have not detected an increased frequency of major congenital malformations or a consistent pattern of malformations among women exposed to lamotrigine compared with the general population. The majority of lamotrigine pregnancy exposure data are from women with epilepsy.

In animal reproduction studies, lamotrigine produced developmental toxicity (e.g., increased mortality, decreased body weight, increased structural variation, neurobehavioral abnormalities) when administered to pregnant animals at doses lower than those used clinically.

Lamotrigine decreased fetal folate concentrations in rats, an effect known to be associated with adverse pregnancy outcomes in animals and humans.

Although preliminary information from the NAAED Pregnancy Registry suggested a possible association between exposure to lamotrigine monotherapy during the first trimester of pregnancy and an increased incidence of cleft lip or cleft palate in infants, this finding has not be observed in other international registries.

The effect of lamotrigine on labor and delivery in humans is unknown.

Physiologic changes during pregnancy may affect plasma lamotrigine concentrations and/or therapeutic effect. Decreased lamotrigine concentrations during pregnancy and restoration of prepartum concentrations after delivery have been reported. Dosage adjustment of lamotrigine may be necessary to maintain clinical response.

Lamotrigine is distributed into human milk. There is some evidence that lamotrigine plasma concentrations in breast-fed infants may be as high as 50% of maternal serum levels. Exposure to lamotrigine in these infants may be further increased due to the immaturity of the infant glucuronidation process required for drug clearance. Apnea, drowsiness, and poor sucking have been reported in nursing infants whose mothers were receiving lamotrigine, although it is not known whether these effects were caused by lamotrigine. It is not known whether lamotrigine can affect milk production.

The known benefits of breast-feeding should be considered along with the mother's clinical need for lamotrigine and any potential adverse effects on the breast-fed infant from the drug or underlying condition.

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