Propranolol elicits cutaneous analgesia against skin nociceptive stimuli in rats

The purpose of this study was to investigate the cutaneous analgesic effect of propranolol and compare with a local anesthetic lidocaine. The potencies and equipotent doses were determined for infiltrative cutaneous analgesia on the rat back by determination of dose–response curves for propranolol and lidocaine. Propranolol as well as lidocaine elicited dose–dependent cutaneous analgesia. On a 50% effective dose (ED50) basis, the relative potency was propranolol (10.3 [8.9–11.9] μmol kg−1) > lidocaine (25.8 [24.3–27.8] μmol kg−1) (P < 0.01). On equianalgesic doses (ED25, ED50, ED75), propranolol produced longer action of infiltrative cutaneous analgesia than lidocaine (P < 0.01). Coadministration of lidocaine (25.8 μmol kg−1) and propranolol (1.7 μmol kg−1) exhibited greater blockade and duration than lidocaine (25.8 μmol kg−1) or propranolol (1.7 μmol kg−1) alone. Propranolol displayed more potent and longer duration of action than lidocaine at producing cutaneous analgesia. Furthermore, propranolol may prove useful as an adjuvant for lidocaine in producing cutaneous analgesia.

► Propranolol produces local but not systemic analgesia in rats.
► Propranolol elicits more potent cutaneous analgesia when compared with lidocaine.
► The sensory block caused by propranolol was longer than that caused by lidocaine.