A majority of patients who are prescribed medications for bipolar disorder do not fill their prescriptions as often as they receive them, a study in the Journal of Affective Disorders has found.
Jonne Lintunen, M.D., Ph.D., of Niuvanniemi Hospital in Kuopio, Finland, and colleagues studied data from Finnish health and prescription registries for 33,131 adults who have bipolar disorder. The patients were diagnosed with bipolar disorder between 1987 and 2018, and the researchers followed dispensing rates of electronic prescriptions from 2015 to 2018. Among all patients, 61.8% had at least one prescription for a mood stabilizer, and 88.6% had at least one prescription for an antipsychotic medication.
Over the four-year follow-up, 59.1% of patients did not fill at least one of their prescriptions for a mood stabilizer or antipsychotic medication. Furthermore, 31% of patients did not fill their prescriptions for a mood stabilizer or antipsychotic medication at least 20% of the time. Among mood stabilizers, lithium had the lowest proportion of nondispensed medications, 11.3%, and valproic acid had the highest, 14.8%. Among antipsychotics that had at least 1,000 prescriptions, clozapine had the lowest proportion of nondispensed prescriptions, 9.0%, and asenapine had the highest, 31.4%. Paliperidone and haloperidol also had high proportions of nondispensed prescriptions, 24.3% and 23.2%, respectively.
Lintunen and colleagues offered a possible explanation for why patients might be more likely to fill their prescriptions for lithium or clozapine than some of the other medications studied.
“Both of these drugs require regular blood tests … ; patients may be more adherent to their medications when they meet health care workers regularly,” they wrote. “In addition, [these medications’] superior effectiveness may explain good adherence: lithium is the most effective mood stabilizer for bipolar disorder and it prevents both manic and depressive episodes. … Similarly, clozapine is known to be the most effective antipsychotic.”
The researchers also found that patients who were younger than 25 years, who were diagnosed with bipolar disorder within the previous three years, or who had four or more previous hospitalizations because of bipolar disorder had twice the odds of not filling at least one prescription for their bipolar medications over the four-year follow-up.
“The high proportion of non-adherent patients is alarming since non-adherence is a well-known risk factor for poor clinical outcomes in bipolar disorder. Therefore, more attention should be given to the reasons why patients choose not to use their medications,” the researchers wrote.
For related information, see the Psychiatric News article “Motivational Pharmacotherapy Can Improve Medication Adherence.”
(Image: iStock/Hiraman)
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