Popular pain relievers may reduce the benefits of commonly prescribed antidepressants, reports the August 2011 issue of the Harvard Mental Health Letter. New research suggests that both acetaminophen (Tylenol) and nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Motrin) may make selective serotonin reuptake inhibitors, or SSRIs, less effective.

Researchers analyzed the results of the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study, a large “real-world” examination of depression treatment. Only 45% of STAR*D participants who took an SSRI along with a pain medication achieved complete relief of depression symptoms, while 55% of people who were taking an SSRI alone (without a pain medication) did so.

It’s not clear why pain relievers might reduce the effectiveness of antidepressants. Research in animals, however, suggests that painkillers interfere with a brain chemical targeted by SSRIs, thereby lessening their impact on the brain.

Dr. Michael Miller, editor in chief of the Harvard Mental Health Letter, notes that people who use pain relievers on a regular basis, and who are not getting enough relief from an SSRI, may want to ease off the pain medication to see if their mood and other symptoms improve. People who need to continue taking pain relievers may want to try other types of antidepressants, such as tricyclics or bupropion, as these drugs do not seem vulnerable to this interaction.

Read the full-length article: "Commentary: Can painkillers cap antidepressant effect?"