Researchers claim to have found two classes of anti-depressants that effectively reduce depression symptoms in cancer patients.

Limited research is available about anti-depressants in treating cancer-related depression. Dartmouth researchers, in a bid to identify best practice for the treatment of depression in cancer, completed a systematic review and meta-analysis of existing research.

The team analyzed nine randomized trials conducted between 1985 and 2011 with 4,700 eligible records of 1,169 patients from various countries. Overall, 83 percent of subjects were female with average age of 54 years.

According to the research, the team identified two classes of antidepressants that reduce symptoms of depression. First is an alpha-2-adrenergic receptor antagonist named Mianserin and second comprises of two selective serotonin reuptake inhibitors: fluoxetine (Prozac) and paroxetine (Paxil)

Researchers explained that available observations indicate that paroxetine and fluoxetine can improve depressive symptoms but may be less well-tolerated.

Miaserin also showed a higher depression response rate compared to placebo, whereas paroxetine and fluoxetine did not. The response rates were low suggesting only modest changes in depressive symptoms.

"All the evidence for alpha-2-andrenergic receptors was based on a single agent, Mianserin," said Natalie Riblet, MD, MPH, lead author of the study, Department of Psychiatry, Geisel School of Medicine. "Unfortunately, the most promising agent, Mianserin, is not available in the US. Given that Mirtazapine is a close pharmacological cousin of Mianserin, there may be clinical benefit to further exploring the role of Mirtazapine in the management of cancer-related depression," Riblets said in a press release.

When researchers analyzed the side effects of the two classes of anti-depressants, they found Mianserin was slightly more tolerable compared to placebos while paroxetine had slightly higher but non-significant dropout rate due to side effects. The team found that fluoxetine had a significantly higher dropout rate than placebos, though this finding became non-significant after removing a study outlier.

"Adverse drug interactions are possible between chemotherapy agents and antidepressants," said Riblet. "Specifically tamoxifen, a common chemotherapy agent, may interact with certain antidepressants to increase risk of serious side effects."

Researchers explained that these two classes work on different neurotransmitters. According to the team, the alpha-2-andrenergic receptor antagonists show particular promise in cancer patients; possibly due to their pharmacological profile that increases norepinephrine and serotonin. Alpha-2-andrenergic receptor antagonists are less likely to cause common serotonin-related side effects such as headache, agitation, jitteriness, or sexual dysfunction, but may contribute to sedation.

"There is a scarcity of evidence to address the role of antidepressants in cancer-related depression," said Riblet. "Our findings suggest there is a need for high-quality randomized clinical trials that explore the role of antidepressants in treating cancer-related depression."

The paper was published in 'General Hospital Psychiatry' in June.