True statement about dezocine is:

Ref: Goodman and Gilman 10/e p602 *Dezocine is slightly more potent and faster acting opioid than morphine with a similar duration of action. It is a paial agonist antagonist opioid. *It is active at u receptors and side effect are similar to those of morphine. *Dezocine doesn't increase plasma histamine and produces less hypotension than morphine or pentazocine. *Dezocine is effective for moderate to severe pain but can cause myocardial depression.