In a recent report, a doctor looked over all the studies for Symbyax. His opinion: it seemed to work for people with bipolar disorder in the short term.
But there wasn’t any research about the drug for people with bipolar disorder who also had other disorders. The combo pill also took away the doctors ability to adjust doses, which can get in the way of managing side effects.
"Ask a doctor which Rx is right for you."
Steven L. Dubovsky, MD, of the State University of New York at Buffalo, looked at the published trials for Symbyax and studies that gave Prozac and Zyprexa together but as separate pills. He found that most of the published trials using the two drugs together had good results. People in the studies showed improvement in their symptoms and had fewer relapses.
However, Dr. Dubovsky pointed out that there were some problems with the published trials that make it hard to know how well Symbyax would work in the real world.
First, all the studies were short term, ranging from six to eight weeks. So the effects of these drugs in combination were not known over longer periods of time.
Second, the published studies only included patients with bipolar disorder, and excluded anyone that had another disorder or problem in addition to bipolar disorder.
Finally, most of the studies were funded by the pharmaceutical industry and did not look at daily function. They focused on improved symptoms, but did not look at how those improved symptoms helped overall functioning.
The combination of Prozac and Zyprexa showed rates of side effects similar to each drug alone. Weight gain and high cholesterol were side effects of both Zyprexa and Symbyax. Serotonin syndrome (a potentially life-threatening drug reaction caused by too much serotonin) was a side effect of Prozac and Symbyax.
Dr. Dubovsky’s opinion after looking over the studies: The one pill option may be easier for patients, but it may take away the doctor’s ability to modify the doses of each drug, which could impact the ability to balance side effects.
He also said that the most common clinical treatment for bipolar disorder is a mood stabilizer, like lithium alone or combined with an antidepressant. No studies to date have compared Symbyax to the mood stabilizer-antidepressant combination.
In his report, Dr. Dubovsky concluded, “Lack of comparison to standard approaches (mood stabilizer alone or in combination with another mood stabilizer and/or an antidepressant) makes it difficult to place the results in the context of standard practice.”
He also commented that getting patients to stay on their meds is important for function, but it can be hard when they have many different meds to take. So there is interest in having a one pill option.
Overall, Dr. Dubovsky concluded that longer term studies are needed to look at both function and symptoms in patients that have more complex (real world) symptoms.
Symbyax, Zyprexa and Prozac are all made by Eli Lilly. Symbyax is currently approved for treatment resistant depression and bipolar disorder. It is made by Eli Lilly and costs between $350 and $700 for 30 tabs depending on dose.
Zyprexa costs between $330 and $1200 for 30 tabs depending on dose. Prozac costs between $200 and $400 for 30 tabs depending on dose. Generic versions of both of these drugs are available.
This opinion report was published January 8 in Expert Opinion on Drug Metabolism & Toxicology. Dr. Dubovsky reported financial links to Eli Lilly, Otsuka, Biogen and Sumitomo.