Analgesics peripheral neuropathies

Type C (continuous) reactions are due to long-term use of the drug (e.g. analgesic nephropathy or peripheral neuropathy with reverse transcriptase inhibitors). 

In a study of painful peripheral neuropathy, CP99.994 (< 100 pg/kg i.v., over 2 h) had no analgesic effect (Suarez et al., 1994). Thus, to date clinical studies indicate that NK1 receptor antagonists are unlikely to be general analgesics (Rupniak and Kramer, 1999). 

Xiao, W., Boroujerdi, A., Bennett, G. J., and Luo, Z. D. (2007). Chemotherapy-evoked painful peripheral neuropathy Analgesic effects of gabapentin and effects on expression of the alpha-2-delta type-1 calcium channel subunit. Neuroscience 144, 714—720. 

The analgesic effect of Tanezumab appears promising, but more research is needed to imderstand how it would be used to manage chronic pain. Even if it is shown to be more effective than standard medications, peripheral neuropathy is a potentially serious adverse event that could limit its use as a first-line medication. 

Pain has been a human problem since the beginning of time but the last decade has seen an explosion of information about the transmitters, receptors and channels involved in the transmission and modulation of noxious messages generated in peripheral tissues. This has lead to the identification of a number of potential new targets for analgesic therapy. We now have more experimental drugs available, which allows us to study the roles of transmitters and receptors in physiological events. There are now numerous animal models for clinical pain states such as inflammation and neuropathies, and these models have shown that several transmitter systems which have minor actions in acute pains can play important roles in more persistent pains. 

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