Nociceptin/orphanin phenylalanine glutamine (N/OFG) is a heptadecapeptide (Meunier et al. 1995; Reinscheid et al. 1995) that affects the sensory innervation of the lower urinary tract in a similar fashion to CAP and RTX. It activates the G protein coupled receptor nociceptin orphan peptide and thus has an inhibitory effect on the micturition reflex in the rat (Lecci et al. 2000).
Following a successful preliminary human study, Lazzeri et al. (2003) confirmed that N/OFG versus placebo is responsible for a significant increase in bladder capacity (p<0.001) and threshold volume of detrusor overactivity (p<0.001), and a non-significant decrease of maximum bladder pressure of the dysfunctional neurogenic bladder. These results were verified in an additional small-scale RCT (n=18) of a 10 day course of N/OFG treatment versus placebo (saline). Statistically significant improvements to bladder capacity (assessed by daily voiding diary) and urine leakage episodes were seen in the treated group but not with placebo (Lazzeri et al. 2006). The authors conclude that this inhibition of the micturition reflex supports nociceptin orphan peptide receptor agonists as a possible new treatment for neurogenic bladders of SCI individuals.
There is level 1a evidence (from two RCTs: Lazzeri et al. 2003; Lazzeri et al. 2006) that supports the use of nociceptin/orphanin phenylalanine glutamine, a nociceptin orphan peptide receptor agonist for the treatment of neurogenic bladder in SCI.