NEW YORK (Reuters Health) - People with Parkinson's disease who also suffer from depression may find they're helped more by an older class of antidepressants than newer types of medication, a small clinical trial sponsored by the National Institutes of Health suggests.
The study found that paroxetine (brand name, Paxil), a so-called SSRI antidepressant, appears to be less effective than the "tricyclic" antidepressant nortriptyline for treating depression in patients with Parkinson's disease.
"Depression in Parkinson's disease is underrecognized, underappreciated and undertreated," lead investigator Dr. Matthew Menza stated in a press release. "This study shows that patients should have hope that they can be helped."
SSRIs are usually prescribed for these patients, Menza, at the Robert Wood Johnson Medical School in Piscataway, New Jersey, and his team note in the journal Neurology. However, they theorized that the tricyclic class of drugs would be more effective than SSRIs, because of the way they work.
The investigators randomly assigned 52 patients with Parkinson's disease and major depression to treatment with nortriptyline, paroxetine CR (controlled release), or an inactive placebo.
Only 34 patients completed the 8-week trial, but based on the available data nortriptyline was seen to be superior to placebo for the change in a standard depression rating scale, whereas paroxetine CR was not.
The percentage of patients whose depression score was halved was 53 percent on nortriptyline, 11 percent with paroxetine CR, and 24 percent for placebo.
Furthermore, only nortriptyline was superior to placebo in improving sleep, anxiety, and social functioning.
However, tricyclics can have more serious side effects than SSRIs, so "people on a tricyclic antidepressant should have their dosages monitored closely by their doctor," Menza added.
In a related editorial, Drs. Michael S. Okun and Hubert H. Fernandez, at the University of Florida in Gainesville, caution that the results may have been compromised by the small number of subjects in the study, its short duration, and the high dropout rate.
They also highlight the safety issue with tricyclic antidepressants, since older people with Parkinson's disease may be more susceptible to side effects such as mental status problems, cardiac issues, and low blood pressure.
SOURCE: Neurology, online December 17, 2008.