ABSTRACT
Opioid medications are widely used clinically for relieving pain and as antidiarrheal and antitussives. Opioid agonists consist of a group of natural, semisynthetic, or synthetic compounds acting on a series of receptors, such as , , and receptors (discussed in Chapters 1 and 2). Concomitant with the ability to relieve pain, these drugs can have adverse effects. Side effects of opioid treatment include nausea, vomiting, constipation, respiratory suppression, fatigue, sweating, difficult micturition, psychomimetic disturbance, and dependence. Another less well-understood adverse effect of opioids is immunosuppression. This immunosuppression may also negatively affect the extent of opioid bowel dysfunction, mainly due to causing deterioration of body function in general.
