Patients receiving MAOIs or triptyline/imipramine type antidepressants. Assure adequate circulatory vol. Avoid HTN; extravasation; infusion into leg veins in elderly patients & those suffering from occlusive disorders (eg, atherosclerosis, arteriosclerosis, diabetic endarteritis, Buerger disease); catheter tie-in technique. Closely monitor BP, IV site & adjust infusion rate. Patients w/ profound hypoxia or hypercarbia. Ensure proper needle or catheter placement prior to, & during infusion. Administer phentolamine when extravasation occurs. Patients w/ asthma or sulfite allergy. Gangrene in a lower extremity. Pregnancy & lactation. Elderly ≥65 yr.