Which of the following is NOT considered an antidepressant?

• A. Amitriptyline
• B. Imipramine
• C. Chlorpheniramine
• D. Phenelzine

Answer: (C)

Antidepressants are drugs that raise monoamine activity in the brain, typically by blocking the reuptake of neurotransmitters like norepinephrine and serotonin or by inhibiting their breakdown. Amitriptyline and imipramine are tricyclic antidepressants that block the reuptake of norepinephrine and serotonin, increasing these neurotransmitters in the synapse. Phenelzine is a monoamine oxidase inhibitor that prevents breakdown of monoamines, also boosting their levels. Chlorpheniramine, on the other hand, is an antihistamine used for allergy relief and does not have antidepressant effects; it does not elevate monoamine neurotransmission for treating depression. So chlorpheniramine is not an antidepressant.