Pharmacology lamotrigine

Treatment of depressive episodes in bipolar disorder patients presents a particular challenge because of the risk of a pharmacologic mood switch to mania, although there is not complete agreement about such risk. Treatment guidelines suggest lithium or lamotrigine as first-line therapy.17,41 Olanzapine has also demonstrated efficacy in treatment of bipolar depression, and quetiapine is under review for approval of treatment of bipolar depression.42 When these fail, efficacy data support use of antidepressants. 

ECT should be considered for more severe forms of depression (e.g., those associated with melancholic and psychotic features, particularly when the patient exhibits an increased risk for self-injurious behavior) or when there is a past, well-documented history of nonresponse or intolerance to pharmacological intervention. Limited data indicate that bipolar depressed patients may be at risk for a switch to mania when given a standard TCA. A mood stabilizer alone (i.e., lithium, valproate, carbamazepine, lamotrigine), or in combination with an antidepressant, may be the strategy of choice in these patients. Some elderly patients and those with acquired immunodeficiency syndrome may also benefit from low doses of a psychostimulant only (e.g., methylphenidate) (see also Chapter 14, The HIV-Infected Patient ). Fig. 7-1 summarizes the strategy for a patient whose depressive episode is insufficiently responsive to standard therapies. 

FIGURE 7—25. Shown here is an icon of lamotrigine s pharmacologic actions. By interfering with sodium channels, lamotrigine is thought to reduce the excitatory actions of glutamate. 

Lathers CM, Schraeder PL, Claycamp HG. Clinical pharmacology of topiramate versus lamotrigine versus pheno-barbital comparison of efficacy and side effects using odds ratios. J Clin Pharmacol 2003 43 491-503. 

Goa KL, Ross SR, Chrisp P. Lamotrigine. A review of its pharmacological properties and clinical efficacy in epilepsy. Drugs 1993 46(l) 152-76. 

Holdrich T, Whiteman P, Orme M, et al. Effect of lamotrigine on pharmacology of the combined oral contraceptive pill (abstract). Epilepsia 1992 32(suppl 1) 96. 

Pharmacology and Mechanism of Action. Lamotrigine blocks voltage-sensitive sodium channels, modulates or decreases glutamate and aspartate release, and has antikindling properties (see Table 68-10)." 2 " ... 

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