ANSWER
Opioid analgesics generally are avoided in patients with head injury for the following reasons:
(a) Opioid-induced pupillary changes, nausea, and general CNS clouding can mask or confuse the neurologic evaluation;
(b) Head injury potentiates the respiratory depressant effects of opioids;
(c) Opioids induce carbon dioxide retention, which in turn causes vasodilation of cerebral arteries and an increase in cerebrospinal fluid pressure that might already be elevated because of head injury
(d) Opioids in excessive doses can mask internal organ injury; and
(e) Morphine and meperidine can produce further hypotension in patients who have blood loss caused by
trauma. These potential complications, However, should not preclude the use of a short-acting opioid, such as fentanyl, for pain control in emergency situations, especially when the patient’s clinical condition
and analgesic responses are monitored closely. If fentanyl is to be used, small but frequent IV doses are preferred over single, large boluses. The final dose is based on the patient’s analgesic and toxic responses. It would be reasonable to start M.C. on fentanyl 25 to 50 mcg IV every 30 to 60 minutes followed by analgesic titration.
