The effects of morphine and methylnaltrexone on gastrointestinal pain in healthy male participants
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The effects of morphine and methylnaltrexone on gastrointestinal pain in healthy male participants. / Brokjaer, A; Olesen, A E; Christrup, L L; Dahan, A; Drewes, A M.
In: Neurogastroenterology and Motility, Vol. 27, No. 5, 05.2015, p. 693-704.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - The effects of morphine and methylnaltrexone on gastrointestinal pain in healthy male participants
AU - Brokjaer, A
AU - Olesen, A E
AU - Christrup, L L
AU - Dahan, A
AU - Drewes, A M
N1 - © 2015 John Wiley & Sons Ltd.
PY - 2015/5
Y1 - 2015/5
N2 - BACKGROUND: Opioid antagonists are increasingly used to abolish the gastrointestinal side effects of opioids. However, they can potentially interfere with local analgesia exerted via opioid receptors in the gut. Thus, in the current study we aimed to explore the effect of rectal morphine before and after blocking opioid receptors outside the central nervous system with methylnaltrexone (MNTX).METHODS: In this randomized, placebo controlled, cross-over study 15 healthy male participants received the following drugs at three separate sessions: (i) placebo, (ii) 30 mg morphine administered per rectum, or (iii) 12 mg MNTX given subcutaneously before 30 mg rectal morphine. At baseline and after drug administration peripheral and central effects of the drugs were assessed by experimental pain to the skin, muscle, rectum and pupillometry.KEY RESULTS: Compared to placebo there was no local effect of morphine on mechanical rectal distension. In contrast, an increase in tolerated volume was seen following MNTX/morphine administration (p < 0.001), starting 7 min after dosing. Both morphine and MNTX/morphine had a central effect manifested as an increase in mechanical muscle pressure thresholds (both p < 0.001) and a decrease in pupil diameter (both p < 0.001). These effects occurred 30 min after dosing.CONCLUSIONS & INFERENCES: No peripheral analgesic effect of morphine was found. Methodological shortcomings may have contributed to the lack of peripheral analgesia and thus, a peripheral morphine effect on rectal pain cannot be excluded. On the other hand, the combination of MNTX and morphine exerted a local effect on rectal distensions and seems to improve analgesia.
AB - BACKGROUND: Opioid antagonists are increasingly used to abolish the gastrointestinal side effects of opioids. However, they can potentially interfere with local analgesia exerted via opioid receptors in the gut. Thus, in the current study we aimed to explore the effect of rectal morphine before and after blocking opioid receptors outside the central nervous system with methylnaltrexone (MNTX).METHODS: In this randomized, placebo controlled, cross-over study 15 healthy male participants received the following drugs at three separate sessions: (i) placebo, (ii) 30 mg morphine administered per rectum, or (iii) 12 mg MNTX given subcutaneously before 30 mg rectal morphine. At baseline and after drug administration peripheral and central effects of the drugs were assessed by experimental pain to the skin, muscle, rectum and pupillometry.KEY RESULTS: Compared to placebo there was no local effect of morphine on mechanical rectal distension. In contrast, an increase in tolerated volume was seen following MNTX/morphine administration (p < 0.001), starting 7 min after dosing. Both morphine and MNTX/morphine had a central effect manifested as an increase in mechanical muscle pressure thresholds (both p < 0.001) and a decrease in pupil diameter (both p < 0.001). These effects occurred 30 min after dosing.CONCLUSIONS & INFERENCES: No peripheral analgesic effect of morphine was found. Methodological shortcomings may have contributed to the lack of peripheral analgesia and thus, a peripheral morphine effect on rectal pain cannot be excluded. On the other hand, the combination of MNTX and morphine exerted a local effect on rectal distensions and seems to improve analgesia.
KW - Administration, Rectal
KW - Adult
KW - Analgesics, Opioid
KW - Cross-Over Studies
KW - Double-Blind Method
KW - Healthy Volunteers
KW - Humans
KW - Injections, Subcutaneous
KW - Male
KW - Middle Aged
KW - Morphine
KW - Muscle, Skeletal
KW - Naltrexone
KW - Narcotic Antagonists
KW - Pupil
KW - Quaternary Ammonium Compounds
KW - Rectum
KW - Skin
KW - Visceral Pain
KW - Young Adult
U2 - 10.1111/nmo.12545
DO - 10.1111/nmo.12545
M3 - Journal article
C2 - 25810023
VL - 27
SP - 693
EP - 704
JO - Neurogastroenterology and Motility
JF - Neurogastroenterology and Motility
SN - 1350-1925
IS - 5
ER -
ID: 162118142