Lamotrigine was approved by the FDA in December 1974. It is marketed in the U.S. and most of Europe as Lamictal by the British multinational healthcare company GlaxoSmithKline. GlaxoSmithKline's official U.S. Lamictal prescribing information can be found here. "Lamictal" in the U.S. has the brand names Lamictal (tablets 25, 100, 150, and 200 mg), Lamictal CD (chewable, 2, 5, and 25 mg), Lamictal ODT (orally disintegrating 25, 50, 100, and 200 mg), and Lamictal XR (extended release, 25, 50, 100, 200, 250, and 300 mg).
Lamictal is a pregnancy category C drug in the U.S. ("Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks") and pregnancy category D in Australia ("Drugs that have caused, are suspected to have caused - or may be expected to cause - an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects").
I suffer from Fabry Disease. The most prominent symptom in my case and the symptom that helped me and my doctor to reach the correct diagnosis was pain in my hands and feet, acroparesthesia (pain in the extremities). My acroparesthesia was unpredictable in "stable" controllable situations (not exercising, not higher temperature environment, which tend to lead to or exacerbate the pain). Sometimes (for hours or more rarely, even days) the pain would be dormant, but would come on suddenly and occur constantly or sporadically for minutes, hours, or days.
The effective dose in my case for eliminating the pain seems to be Lamictal tablet 100mg at morning and 100mg in the evening. Anything below that seems less effective or ineffective at lessening or eliminating the pain. I have personally experienced no side effects from taking Lamictal. Before she prescribed Lamictal, my first doctor prescribed me Neurontin (Gabapentin) but this did nothing for the pain. It was then that I was put on Lamictal, which stopped the pain in its tracks. My second doctor tried me out on Lyrica (Pregabalin) (stopping the Lamictal temporarily) but this medication also had absolutely no effect on the pain.
Across the internet I have come across personal accounts of Lamictal helping with pain from Trigeminal Neuralgia and cluster headaches. Conversely, note that side effects of Lamictal can include abdominal pain and painful menstrual periods.
An article on "Lamotrigine in the treatment of pain syndromes and neuropathic pain" can be found here.