Why do cannabinoids not show consistent effects as analgetic drugs in multiple sclerosis?

Abstract

The effectiveness of cannabinoids (CB) in the treatment of pain in patients with multiple sclerosis (MS) varies. The pathogenesis of pain in MS is diverse as are the possible effects of CB at different sites of CB receptors in the peripheral and central nervous system, this may explain the variable impact on individual patients. The aim of this review is to summarize pre-clinical and clinical studies to explain this variability from a neuropharmacological point of view. Future studies are needed to examine specific effects on distinct symptoms in homogenous groups of patients.

Symptomatic therapy in multiple sclerosis

“…There have been several studies exploring the role of oral synthetic delta-9-tetrahydrocannabinol (dronabinol) in reducing MS-related pain and spasticity. It was suggested to reduce spasticity-related pain [Lienau et al 2007].…”

Managing neuropathic pain with Sativex®: a review of its pros and cons

“…Lienau et al [27] covered this issue with a recent review in which the role of cannabinoids as analgesic drugs for MS pain is seriously doubted. The main argument put forward is that most of the clinical reports are based on a very low number of patients.…”