title: An isobolographic analysis of the antinociceptive effect of xylopic acid in combination with morphine or diclofenac.
abstract: BACKGROUND
  A common practice of managing pain globally is the combination of analgesics and this is aimed at facilitating patient compliance, simplifying prescription, and improving efficacy without increasing adverse effects. Fruit extracts of Xylopia aethiopica are used traditionally in the management of pain disorders and xylopic acid (XA) present in the fruit extract have been shown to possess analgesic properties in animals. There is the likelihood of concomitant use of XA and the commonly used analgesics in traditional settings. This study, therefore, evaluated the pharmacologic interaction between XA/morphine and xylopic/diclofenac combinations.
  
  
  METHODS
  The formalin test and acetic acid writhing test were used to study the antinociceptive activity of XA, morphine, and diclofenac. The isobolographic analysis was used to study the antinociceptive interactions between XA co-administered with morphine or diclofenac.
  
  
  RESULTS
  Results obtained revealed that XA (10-100 mg/kg), morphine (1-10 mg/kg), and diclofenac (1-10 mg/kg) produced dose-related antinociception with different potencies in the formalin and acetic acid writhing tests. Isobolographic analysis of XA/morphine and XA/diclofenac combinations revealed potentiation of their antinociceptive effects. The degree of potentiation calculated as interaction index showed synergism for both combinations in all the nociceptive tests.
  
  
  CONCLUSIONS
  In conclusion, the present study demonstrated synergism for the co-administration of XA with morphine or diclofenac.
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
authors.forename: Eric
authors.initials: E
authors.lastname: Woode
authors.affiliation: Department of Biomedical and Forensic Sciences, School of Biological Science, University of Cape Coast, Cape Coast, Ghana.
authors.forename: Elvis Ofori
authors.initials: EO
authors.lastname: Ameyaw
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
authors.forename: Wonder Kofi Mensah
authors.initials: WK
authors.lastname: Abotsi
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
authors.forename: Eric
authors.initials: E
authors.lastname: Boakye-Gyasi
keywords: Isobologram; mice; nociception; potentiation; synergism