Which of the following is an example of a selective serotonin reuptake inhibitor (SSRI)?

Fluoxetine is classified as a selective serotonin reuptake inhibitor (SSRI), which is a category of antidepressants commonly used to treat conditions such as depression, anxiety, obsessive-compulsive disorder, and panic disorder. The mechanism of action for SSRIs like fluoxetine involves the selective inhibition of the reuptake of serotonin in the brain, leading to increased levels of serotonin in the synaptic cleft. This enhancement of serotonin availability is associated with mood elevation and improved emotional regulation, making SSRIs effective for their intended therapeutic uses.

Other medications listed do not belong to the SSRI class and serve different purposes. For example, ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that is primarily used for pain relief and to reduce inflammation. Hydrocodone is an opioid medication used for pain management, acting primarily on the mu-opioid receptors. Diphenhydramine is an antihistamine used for allergy relief and has sedative properties. Each of these drugs works through different mechanisms and targets different receptors in the body, illustrating the specific and unique role SSRIs like fluoxetine play in the treatment of mood disorders.