Analgesic effects of morphine in combination with adjuvant drugs in rats.
BACKGROUND
Morphine is co-administered with adjuvant drugs to treat pain, nausea, vomiting, dyspnoea and delirium in cancer patients.


OBJECTIVE
To investigate analgesic effects of morphine when co-administered with adjuvant drugs.


METHODS
Two-month-old male Wistar rats received single morphine doses alone (0.45 and 0.9 mg/kg) or with midazolam (0.3 mg/kg), haloperidol (0.15 and 0.45 mg/kg), levomepromazine (0.35 mg/kg), metoclopramide (1.0 mg/kg), and hyoscine butylbromide (1.7 mg/kg) as single subcutaneous injections. Analgesia was measured by the tail-flick test after 15, 30, 45, 60, and 90 min of drug administration. In the case of significant analgesia enhancement, analgesic and sedative effects were explored in 3-, 5-, 6-, 8-, and 11-month-old rats.


RESULTS
Significant morphine (0.9 mg/kg) analgesia enhancement was observed 60 min after haloperidol (0.15 and 0.45 mg/kg) and hyoscine butylbromide co-administration. The addition of haloperidol to morphine significantly increased analgesia in 6-, 8- and 11-month-old rats while in the case of hyoscine butylbromide co-administration this effect was observed only in 11-month-old rats.


CONCLUSIONS
Haloperidol and hyoscine butylbromide enhanced morphine analgesia. Future studies may explore the repeated administration of these drug combinations in rats and humans.
Chair and Department of Palliative Medicine, Poznan University of Medical Sciences, Poznan, Poland.
Wojciech
W
Leppert
Irena
I
Okulicz-Kozaryn
Ewa
E
Kaminska
Michal
M
Szulc
Przemyslaw
P
Mikolajczak
D000277:Adjuvants, Pharmaceutic / Q000627:therapeutic use*; D000701:Analgesics, Opioid / Q000627:therapeutic use*; D000818:Animals; D002086:Butylscopolammonium Bromide / Q000627:therapeutic use; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D006220:Haloperidol / Q000627:therapeutic use; D008297:Male; D008728:Methotrimeprazine / Q000627:therapeutic use; D008787:Metoclopramide / Q000627:therapeutic use; D008874:Midazolam / Q000627:therapeutic use; D009020:Morphine / Q000627:therapeutic use*; D010146:Pain / Q000188:drug therapy*; D017208:Rats, Wistar
D000277:Adjuvants, Pharmaceutic; D000701:Analgesics, Opioid; D002086:Butylscopolammonium Bromide; D009020:Morphine; D008728:Methotrimeprazine; D006220:Haloperidol; D008787:Metoclopramide; D008874:Midazolam