Antinociceptive Evaluation of Antidepressants (Cita- lopram, Duloxetine and Amitriptyline) in a Mouse Model of Acute Pain

Abstract

Introduction: Acute pain is a pervasive and debilitating symptom affecting the general population as well as depressed patients who suffer even more from pain and fatigue. Aims and Objectives: To evaluate the antinociceptive effect induced by antidepressants (Citalopram, Duloxetine and Amitriptyline) in acute pain induced in mice. Place and Duration of study: Animal Research Laboratory of University of Lahore. Study Period: 2018- 2019 Material and Methods: An experimental animal study was carried out on 25 albino mice. The mice were divided into 5 groups; Group 1: Positive Control (PC), Group 2: Ibuprofen (IBO) (Standard) 80mg/kg, Group3: Citalopram (CTP)3mg/kg, Group 4: Duloxetine (DXT) 25mg/kg, Group 5: Amitriptyline (AMT) 15mg/kg. Groups 2-5 were administered drugs orally through a feeding tube as per group designation while Group 1: Control was given an equivalent amount of normal saline. One hour post treatment with test drugs, all Groups (1-5) were injected 10 ml/ kg of 2% acetic acid I/P and number of writhing movements consisting of contraction of abdominal muscles leading to extension of hind limb and periodic arching of body as well as paw licking behavior were counted for 20 minutes at 5- minute interval, using hand tally counter. Degree of analgesia was calculated by using formula of percentage effectiveness. Data was entered and analyzed utilizing SPSS version 21, p?0.05 was taken as significant. Results: Ibuprofen completely eliminated the nociceptive outcome of diluted acetic acid in writhing and licking of experimental animals. Citalopram, showed maximum decreasing effect (95%-96%) in writhing in 5-20 min. However, its effect in paw licking was low. Duloxetine showed 70% to 90% decrease in writhing at 5-20 min whereas 100 % inhibition of paw-licking was observed at 5 to 20 minutes. The writhing effect of amitriptyline was 77%-90% at 5-20 min and paw licking effect was 80-90 % at 5-20 min. Conclusion: Amitriptyline, duloxetine and citalopram have significant effect in reducing the acute nociceptive pain and may be utilized as analgesic in acute state of pain.