title: Study of interaction of tramadol with amlodipine in mice.
abstract: OBJECTIVE
  To study a possible interaction between tramadol, an opioid analgesic and amlodipine, a dihydropyridine calcium channel blocker with proposed antinociceptive property.
  
  
  METHODS
  Albino mice of Haffkine strain were used for the study. The experiment was carried out using tail-flick method. Different doses of tramadol (50 mg/kg, 22.8 mg/kg and 10 mg/kg) were administered intraperitoneally to select the nonanalgesic dose. The animals were treated with different doses of amlodipine (2.5 mg/kg, 3.0 mg/kg, 3.5 mg/kg) to study its antinociceptive action. Combination of different doses of both the drugs were administered to study antinociceptive effect of the combination.
  
  
  RESULTS
  Tramadol, showed dose dependent antinociception which persisted for entire two hours of the study period. Antinociceptive action was seen with amlodipine at a dose of 3.5 mg/kg. Different doses of amlodipine (2.5 mg/kg, 3.0 mg/kg) in combination with the nonanalgesic dose of tramadol (10 mg/kg) produced a significant enhancement of antinociceptive effect of tramadol. Combination of 3.5 mg/kg dose of amlodipine with nonanalgesic dose of tramadol (10 mg/kg) further enhances antinociceptive activity.
  
  
  CONCLUSIONS
  It is concluded that combination of amlodipine, a N - type calcium channel blocker, with tramadol produce significant enhancement of antinociceptive activity of tramadol.
authors.affiliation: Department of Pharmacology, Medical College, Baroda, Gujarat, India.
authors.forename: Hiral
authors.initials: H
authors.lastname: Modi
authors.forename: Bipa
authors.initials: B
authors.lastname: Mazumdar
authors.forename: Jagatkumar
authors.initials: J
authors.lastname: Bhatt
mesh_terms: D017311:Amlodipine / Q000008:administration & dosage / Q000494:pharmacology*; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005260:Female; D008297:Male; D051379:Mice; D010146:Pain / Q000188:drug therapy*; D010147:Pain Measurement; D011930:Reaction Time / Q000187:drug effects; D014147:Tramadol / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000700:Analgesics; D000701:Analgesics, Opioid; D002121:Calcium Channel Blockers; D017311:Amlodipine; D014147:Tramadol
keywords: Amlodipine; tail flick latency; tramadol
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