No, it is not a monoamine oxidase inhibitor (MAOI).

Losartan is not a monoamine oxidase inhibitor. It is an Angiotensin Receptor Blocker.

A drug that inhibits the absorption of the enzyme monoamine oxidase.

This is an addition to the above-mentioned answer.

To be more specific, monoamine oxidase inhibitor (MAOIs) is an antidepressant which indirectly inhibits the degradations of monoamine by directly inhibiting the enzyme responsible for this degradation process (that enzyme is monoamine oxidase).

No oxycodone is a narcotic painkiller opiate not an antidepressant.

Melatonin should not be taken by people using certain antidepressants, such as Prozac (a serotonin inhibitor) or Nardil (a monoamine oxidase inhibitor).