Approaches to reducing the incidence of lamotrigine-induced rash

Lamotrigine has been used to treat over a million patients worldwide, inclu ding about 4000 adults and over 1000 children in clinical trials. It is a v aluable broad spectrum drug that is well tolerated and has few adverse effe cts apart from skin rash. Most of the rashes are mild but some Severe, life -threatening skin reactions have been reported. The available evidence does not indicate that either the mild or the severe skin rashes are any more c ommon with lamotrigine than with carbamazepine, phenytoin or phenobarbital (phenobarbitone). In vitro lymphocyte transformation tests suggest that an immune mechanism is involved. The incidence of rash with lamotrigine can be reduced by using starting dos es and dose-escalation rates that are no higher than those recommended, esp ecially in patients who are receiving comedication with valproic acid (sodi um valproate), which prolongs the half-life of lamotrigine. Consideration m ight be given to using even lower dose schedules than those currently recom mended to reduce the incidence of rash further. Any patient who develops a rash or who becomes unwell in the first few week s of treatment should be evaluated promptly by a physician. Lamotrigine sho uld be stopped immediately if the rash or illness could be attributed to th e drug. Reintroduction after initial rash has been achieved but is not reco mmended without close specialist supervision and should not be undertaken i f the initial reaction was serious. Details of serious reactions should be reported to the appropriate national drag safety agency to provide informat ion that will allow further improvements in the risk/benefit ratio. Extensive data have shown that lamotrigine is a valuable anticonvulsant dru g that has few adverse effects if it is used correctly.