Selective NPFF receptor antagonist (Ki values are 58 and 75 nM at hNPFF1 and hNPFF2 receptors respectively). Displays selectivity over several related receptors including NPY Y1 GPR10, GPR54, GPR103 and the opioid receptors. Blocks NPFF-induced hypothermia and increases in atrial blood pressure and heart rate, and prevents opioid-induced tolerance associated with hyperalgesia in vivo.