Lithium, Divalproex Appear Effective, Well-Tolerated in Older Adults With Bipolar Mania

Lithium and divalproex are both well-tolerated and effective at controlling mania in older adults with bipolar disorder, reports a study in AJP in Advance. The observed rates of response or remission were similar to rates reported in younger patients with bipolar disorder despite this study using lower medication dosages and serum concentrations. 

“Our main findings, if confirmed, have implications for geriatric practice and investigation,” wrote lead author Robert Young, M.D., of Weill Cornell Medicine and colleagues. “Treatment with lithium or divalproex with conservative serum concentration targets, combined with limited use of rescue and adjunctive medications, was tolerated by older patients with mania, and it benefited a substantial proportion of them.” 

For the study, Young and colleagues compared the tolerability and efficacy of lithium and divalproex in 224 inpatients and outpatients aged 60 years or older with bipolar I disorder who presented with a manic, hypomanic, or mixed episode. The patients were randomly assigned to either lithium (target serum concentration, 0.80–0.99 mEq/L) or divalproex (target serum concentration, 80–99 μg/mL) for nine weeks. All study participants received standard behavioral interventions, such as a reduction of excess social stimuli.

During the first three weeks of treatment, patients received lorazepam if they had significant anxiety, agitation, or insomnia, and then oral risperidone if they failed to respond to the lorazepam and behavioral intervention. Only 17% and 14% of the participants taking lithium and divalproex, respectively, required rescue risperidone.

After nine weeks, manic symptoms, as assessed by the Young Mania Rating Scale (YMRS), improved significantly in both groups, with the lithium group averaging 3.90 points better. Response rates (50% or greater reduction in YMRS score) were 78.6% for lithium and 73.2% for divalproex; rates of remission (YMRS score ≤9) were 69.6% for lithium and 63.4% for divalproex. 

Contrary to expectations based on existing literature, divalproex did not induce higher rates of sedation than lithium. However, as has been previously found, lithium did result in more cases of tremor. Other side effects, including nausea and weight gain, were similar in both groups.

For related information, see the Psychiatric News PsychoPharm article “Lurasidone May Work Better as Monotherapy in Older Patients With Bipolar Depression.”

(Image: iStock/fzant)