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Effects of lamotrigine and lithium on body weight during maintenance treatment of bipolar I disorder

Authors


  • GS has received funding from Abbott Laboratories, GlaxoSmithKline Pharmaceuticals, Janssen Pharmaceutica, Eli Lilly & Co., Bristol-Myers Squibb, Solvay, Novaris, Sanofi, AstraZeneca Pharmaceuticals, and Pfizer Pharmaceuticals; and is a consultant for Abbott Laboratories, GlaxoSmithKline Pharmaceuticals, Janssen Pharmaceutica, Eli Lilly & Co., Bristol Myers Squibb, Novartis, Elan, Sanofi, Sigma-Tau, and AstraZeneca Pharmaceuticals. CB has received research grants from Abbott Laboratories, Bristol-Myers Squibb, Elan Pharmaceuticals, GlaxoSmithKline, Janssen, Lilly Research, the National Institute of Mental Health, Parke Davis, R.W. Johnson Pharmaceutical Institute, SmithKline Beecham, and Stanley Medical Research Foundation; and is a speaker or a consultant for Abbott Laboratories, AstraZeneca, GlaxoSmithKline, Janssen, Lilly Research, Pfizer, and Sanofi Synthelabo. JRC has received funding from the National Institute of Mental Health, Abbott Laboratories, Ciba-Geigy, Merck, GlaxoSmithKline, Janssen Pharmaceutica, Lilly Research Laboratories, MacArthur Foundation, National Alliance for Research in Schizophrenia and Affective Disorders, Parke-Davis Pharmaceuticals, Robert Wood Johnson Pharmaceutical Research Institute, Sandoz Pharmaceuticals Corporation, SmithKline Beecham Pharmaceuticals, Stanley Foundation, Tap Holdings, Inc., UCB Pharma, and Wyeth Ayerst Pharmaceuticals; and is a consultant/participates in Advisory Boards for Abbott Pharmaceuticals, AstraZeneca, Bristol Myers Squibb/Otsuka, Eli Lilly & Co., GlaxoSmithKline, Janssen Cilag, Novartis, Parke-Davis/Warner Lambert, Robert Wood Johnson Pharmaceutical Research Institute, Shire Labs, SmithKline, TAP Holdings, Teva Pharmaceuticals, and UCB Pharma. TK has received grants from Abbott Laboratories, AstraZeneca, Bristol-Myers Squibb, Elan Pharmaceuticals, Eli Lilly & Co., GlaxoSmithKline, Janssen Pharmaceutica, Novartis, and Shire Laboratories; is a consultant for Abbott Laboratories, AstraZeneca, Bristol-Myers Squibb, Cephalon, Elan Pharmaceuticals, Eli Lilly & Co., GlaxoSmithKline, Janssen Pharmaceutica, Novartis, Pfizer, and Shire Laboratories; and has received lecture honoraria from Abbott Laboratories, AstraZeneca, Bristol-Myers Squibb, Eli Lilly & Co., GlaxoSmithKline, Janssen Pharmaceutica, Novartis, and Pfizer. TT, RW and BB are employees of GlaxoSmithKline.

Gary Sachs, MD, Department of Psychiatry, Harvard University, Harvard Bipolar Research Program, Massachusetts General Hospital, 50 Staniford Street, Suite 580, Boston, MA 02114, USA. Fax: 617-726-6768;
e-mail: sachsg@aol.com

Abstract

Objective:  The effect of lamotrigine maintenance therapy on body weight was assessed retrospectively in analyses of data from two double-blind, placebo- and lithium-controlled, 18-month studies in patients with bipolar I disorder (n = 227 for lamotrigine, 190 for placebo, 166 for lithium).

Methods:  Endpoints included mean change in weight, the percentage of patients with ≥7% change (increase, decrease, fluctuation) in weight, and the percentage of patients with weight-related adverse events during double-blind treatment.

Results:  Mean weight remained stable during maintenance therapy with lamotrigine. In a mixed-model repeated-measures analysis, mean changes in weight (kg) at week 52 were −1.2 with lamotrigine, +0.2 with placebo, and +2.2 with lithium [estimated difference (95% CI) lamotrigine minus placebo = −1.3 (−3.6, 0.9), p = 0.237; lithium minus placebo = +2.0 (−0.3, 4.4), p = 0.094; lithium minus lamotrigine = +3.4 (1.4, 5.4), p < 0.001]. Analyses were truncated at week 52 because of the high incidence of missing data at later time points. The percentages of patients with a ≥7% weight gain, during randomized treatment, were 10.9%, 7.6% and 11.8% for the lamotrigine, placebo, and lithium groups, respectively. The percentages of patients with a ≥7% weight loss, during randomized treatment, were 12.1%, 11.5%, and 5.1% for the lamotrigine, placebo, and lithium groups, respectively. The percentage of patients with a ≥7% weight loss did not significantly differ between lamotrigine and placebo but was significantly higher with lamotrigine than lithium. The incidences of ≥7% weight changes and of weight changes reported as adverse events were comparable between active treatments and placebo.

Conclusion:  Lamotrigine was associated with stable body weight during 1 year of treatment and was comparable to placebo in mean weight change, incidence of clinically significant weight change, and incidence of weight changes reported as adverse events in patients with bipolar disorder. Lithium was associated with weight gain, but the magnitude of lithium-associated weight gain was lower in the current analysis than in previous studies.

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