Lamotrigine, popularized in the Europe and States as Lamictal is a routinely prescribed drug for treatment of epilepsy, bipolar disorder and seizures. Marketed by GlaxoSmithKline, this anticonvulsant is phenyltriazine by its chemical nature. The first effective stabilizer, the drug dose cause blockage of sodium channel pathways. The drug comes with a warning that says fatal skin reaction can occur inclusive of Stevens–Johnson syndrome, DRESS syndrome and toxic epidermal necrolysis. Statistics suggest dosing has a 5 to 10 percent chance of developing a rash and if so happens, the patient should discontinue usage and consult the physician. The level must be kept in check as overdose can trigger serious skin issues. The manufacturer has made it available in scored tablets as well as chewable ones that are of lower milligram strength. 2008 onwards Teva made it available in generic form as well. GSK has launched its extended version (shortened as Lamictal XR) that is basically the regular one with a coating that goes by patented name DiffCORE.
Adult dosage for patients with seizure prophylaxis:
The patients taking antiepileptic drug containing Valproic Acid need to receive 25 mg every alternate day for the first two weeks. From third week onwards, 25mg dosage is to be taken every single day till the end of fourth week. 100 to 400 mg/day is the usual maintenance dose and it can be changed to 25 to 50 mg/day to sustain the maintenance after passage of every 1 or 2 weeks.
For those having antiepileptic drugs without Valproic Acid, the first two week dosage must be 50 mg/day followed by 100 mg/day of divided dosage in next two weeks. Divided doses of 300 to 500 mg/day can be used for maintenance.
For xr generic lamotrigine doses, the dosage can be elevated in case of primary generalized tonic-clonic and partial onset seizures. For patients who are not having Carbamazepine, Phenytoin, Phenobarbital, Primidone or Valproate, the first two weeks should be 25mg daily followed by 50mg daily till end of the month. The daily dosage for fifth week is 100 mg, for the sixth week is 150 mg, seventh week is 200mg and finally for eighth week is 300-400 mg. For patients taking all the above except Valproate, the amount is roughly doubled for each dose.
In case of an overdose, the concerned doctor and patients should take a note of the helpline number 1-800-222-1222 (the American Association of Poison Control Centers), website http://www.aapcc.org to track the local poison control center or the emergency room in the hospital.
Dosage for children with seizure prophylaxis
The dosage variations largely depend on the age, body mass and other parameters of the child. For 2 to 12 year age group, tablets need to be prescribed. Children up to 6 years are likely to require the highest dosage, with weight less than thirty kilograms likely to receive half times more dosage than those who weight above the threshold.
Patients, who consume AEDs except carbamazepine, phenytoin, phenobarbital, primidone, or valproic acid, require divided 0.3 mg/kg/day doses to nearly the whole tablet for first two weeks. Divided doses of 0.6 mg/kg/ are to be consumed for the following two weeks. The maintenance doses are of 4.5 to 7.5 mg/kg/day with the maximum peaking at 300 mg/day. Xr Generic medicines can be used for children with seizure prophylaxis.
For those having AED including valproic acid, 0.15 mg/kg/day in 1 to 2 divided doses for initial two weeks and 0.3 mg/kg/day in same dosage pattern till fourth week. After a month is over, maintenance doses are to be calculated at 0.3 mg/kg/day added to previous dose. The maximum should not exceed 200 mg/day.
Patients having the same without valproic acid require 0.6 mg/kg/day for first two weeks and 1.2 mg/kg/day for the following two weeks in similar dosage pattern. The maintenance dosage should be 5 to 15 mg/kg/day with maximum level being 400 mg/day.
Dosage for adults with bipolar disorder:
For patients not taking carbamazepine, the dosage for bipolar disorder are 25 mg/day till 2nd week, 50mg/day till 4th week, 100mg in 5th week and 200 mg till 7th week. The patients having carbamazepine but no valproate, require doubled dosage for depression till 5th week followed by 300mg in 6th week and 400mg in 7th week. For those having valproate, it is 25mg daily in during the first week and rest of the dosage is halved for patients not taking carbamazepine.