Morphine rapidly changes human brain
Although it is controversial, the use of morphine in chronic, nonmalignant pain is very common. Its deleterious side effects are well documented, including but not limited to dependence and tolerance to analgesic effect, addiction and hyperalgesia (increased sensitive to pain)(1-3). A recent study published in Pain by Younger and colleagues observed that short-term usage of morphine changed human brain in patients with chronic low back pain, and the changes in human brain did not reverse 3-6 months after stopping the use of morphine (4).
Ten individuals with chronic low back pain were administered oral morphine daily for 1 month. High-resolution anatomical images of the brain were acquired immediately before and after the morphine administration period. Thirteen regions in the brain evidenced significant volumetric change, and degree of change in several of the regions was correlated with the amount of morphine used, primarily in the right amygdala, where is involved in drug-induced associative learning, drug craving, reinforcement, development of dependence and the experience of acute withdrawal. The morphine use associated changes were also observed in the right hypothalamus, where is essential for cognitive arousal and attention, in the left inferior frontal gyrus, right ventral posterior cingulate, and right caudal ponsThe results suggest that opioid exposure causes structural and functional changes in .Follow-up scans that were conducted an average of 4.7 months after cessation of opioids demonstrated many of the morphine-induced changes to be persistent. By contrast, 9 individuals consuming blinded placebo capsules for 6 weeks evidenced no significant morphologic changes over time.
Morphologic changes occur rapidly in human brain during new exposure to prescription opioid analgesics. The deleterious side effects on brain of morphine persist after the cessation of its use.
1. Benyamin R, Trescot AM, Datta S, et al. Opioid complications and side effects. Pain Physician 2008;11:S105?20.
2. Ballantyne JC, Mao J. Opioid therapy for chronic pain. N Engl J Med 2003;349:1943?53
3. Angst MS, Clark JD. Opioid-induced hyperalgesia: a qualitative systematic review. Anesthesiology 2006;104:570?87.
4. Younger JW, Chu LF, et al. Prescription opioid analgesics rapidly change the human brain. Pain 2011; 152:1803-10.