Tegretol is a brand name while lithium is a chemical name. Tegretol (also called Tegrital) contains carbamazepine. Although concurrent use is beneficial in some patients, mild (confusion, drowsiness, weakness, lethargy, coarse tremors) to severe neurotoxicity (ataxia, truncal tremors, nystagmus, limb hyperreflexia, muscle fasciculations) is reported to have developed in some and possibly sinus node dysfunction in others. The incidence of neurotoxic interaction is not known. If concurrent use is undertaken the patient should be closely monitored.