A patient presented with pain in the right lower quadrant of abdomen. He has history of renal stones in right kidney. He was prescribed an opioid which is agonist at kappa receptors and antagonist at mu receptors. The likely drug given was:
(A) Pentazocine (B) Buprenorphine (C) Tramadol (D) Fentanyl
(A) Kappa agonist and mu antagonist are:Pentazocine, nalbuphine, butarphanol.They are responsible for causing dysphoria as a side effect.Buprenorphine is paial mu agonist and kappa antagonist.Tramadol and fentanyl are synthetic opioids.