Tramadol N-oxide

Tramadol N-oxide (T-N-O) (RWJ 38705) is an analgesic. In animal models such as the mouse abdominal constriction test, 48°C and 55°C hot plate tests, and the tail-flick assay, Tramadol N-oxide demonstrates a dose-dependent and prolonged analgesic effect. Its affinity for opioid μ receptors (Ki = 38.5 μM) and δ or κ receptors (Ki > 100 μM) is negligible. Tramadol N-oxide is used for researching analgesic effects.