Zoloft is not a monoamine oxidase inhibitors, or MAOI, according to WebMD. Zoloft belongs to a class of antidepressants called selective serotonin reuptake inhibitors, or SSRIs, which work by affecting the way the body's chemical messengers, or neurotransmitters, work.
By blocking the reabsorption of serotonin, SSRIs change the balance of chemicals in the brain, which often results in a better mood, according to Mayo Clinic. Monoamine oxidase inhibitors work by blocking a natural enzyme, called monoamine oxidase, from breaking down not only serotonin, but also epinephrine and dopamine as well, states WebMD. This causes an elevation of all three neurotransmitters in the brain. However, blocking the enzyme action of monoamine oxidase can also interfere with the breakdown of other medicines, such as Sudafed, which can cause serious complications.