Bipolar disorder in geriatric populations and which bipolar medications are effective for treating seniors with bipolar.

“With respect to bipolar disorder in geriatric populations, we, in fact, do not have published guidelines,” began Martha Sajatovic, MD, in her address at the 17th Annual Meeting of the American Association for Geriatric Psychiatry. While there are guidelines for the treatment of bipolar disorder in general populations, these guidelines are “certainly not cookbooks for clinicians but really offer us some guideposts and helpful recommendations for a very complex condition in our patients,” she acknowledged.

But what do the guidelines, such as those published by the American Psychiatric Association, the Veterans Administration (VA), and the British Association for Psychopharmacology, say about treatment for late-life bipolar disorder? Dr. Sajatovic cautioned that this sizable patient population has unique issues, since older individuals who develop bipolar disorder may have a new-onset form of the illness. “We can estimate, based on existing data, that the prevalence rate is 10% in individuals older than 50. And that surprises a lot of people who have the idea it is a rare bird.”

No Data, Just the Facts

While treatment for older patients may follow the same principles as for other patient groups, there is a severe scarcity of data specific to late-life bipolar disorder, explained Dr. Sajatovic, who is Associate Professor in the Department of Psychiatry at Case Western Reserve University School of Medicine, Cleveland. “In fact, if you look at treatment guidelines, they really only address the care of older people with bipolar disorder in very general ways. A lot is speculation. What we do not have are clear and specifically focused treatment guidelines for bipolar disorder in later life.”

What happens in the absence of clear, evidence-based guidelines? She cited a study by Shulman et al in which his team analyzed community prescription trends in individuals older than 66 from an Ontario, Canada, drug benefit program from 1993 to 2001. “Very interestingly, during that time period, the number of new lithium prescriptions fell from 653 to 281. The number of new valproate users went from 183 to over 1,000 in 2001.

“The number of new valproate users surpassed the number of new lithium users in 1997, so while the curve from the lithium was going down, the curve for the valproate was going up, and crossed in 1997. This trend was seen even when patients with dementia were excluded from the analysis, so really, it was for late-life bipolar disorder. Clearly, clinicians and patients are talking with their feet here. We do not have data that say this is what you should do, but this is what’s happening.”

VA vs Community

Dr. Sajatovic also reviewed a study of a VA psychosis registry, looking at bipolar disorder in the VA system and age-related modifiers of clinical care. Interestingly, she reported, there are more than 65,000 individuals in the VA database with bipolar disorder, and more than a quarter are older than 65. “You don’t have to be a statistician to figure out where we’re going with this. There are a large number of individuals who are progressing into a later-life diagnosis of bipolar disorder.”

Once the bipolar disorder group was identified, Dr. Sajatovic focused on their drug treatment patterns, which contrasted with those of Shulman et al’s findings. Individuals were stratified into three age-groups: 30 and younger, 31 to 59, and 60 and older. She found that 70% of patients who had been prescribed a mood stabilizer were receiving lithium. “In the VA system, lithium was the mood stabilizer of choice, by a long shot. Very different from what’s happening in the community,” she noted. Dr. Sajatovic allowed that it was not clear if these were patients already being treated with lithium, or if the findings were a reflection of the VA population, which is followed for a longer time than a fragmented community sample.

The use of valproate was seen in 14% to 20% of the VA population, which is quite a bit lower than the use of lithium; carbamazepine use was similar to valproate. “There were a small number who were on two or more agents—again, different from a community sample where you see a lot more polypharmacy,” she observed.

It is an interesting story, as well, with the use of antipsychotic medications, as Dr. Sajatovic reported that 40% of patients were prescribed oral antipsychotics. Olanzapine was the most commonly prescribed atypical antipsychotic in the VA system, across age-groups, followed by risperidone, although risperidone did not yet have an FDA indication for bipolar disorder.

The Pros and Cons of Lithium

Lithium is the most extensively studied medication for bipolar disorder in the elderly. It is an effective mood stabilizer in older adults and has an antidepressant effect with some patients, said Dr. Sajatovic. The frequency of acute toxicity with lithium in geriatric patients is reported to range from 11% to 23%, and in medically ill patients the rate can be as high as 75%.

Based on her experiences, Dr. Sajatovic made the following recommendations to clinicians: When prescribing lithium for the elderly, reduce the dose by one third to half of that given to younger patients; the dose should not exceed 900 mg/day. A baseline screening for renal function, electrolytes, and fasting blood glucose, as well as an EKG, should be conducted. “There is some controversy about target serum concentrations. What we know from the geriatric data is that patients who are at higher blood levels have better control of their bipolar disorder symptoms but are more likely to get toxic. So they are likely to tolerate lower blood levels and need to maintain their treatment with lower blood levels.” Lithium can be a problem, especially at the higher blood levels, she said.