Ibudilast is a relatively nonselective phosphodiesterase inhibitor which has 
been marketed for almost 20 years in Japan for treating asthma. More recently it 
has been found to have anti-inflammatory activity in both the peripheral immune 
system and in the CNS via glial cell attenuation. This CNS-directed 
anti-inflammatory activity is of potential use in the treatment of multiple 
sclerosis, neuropathic pain, and in the improved efficacy and safety of opioids 
by decreasing opioid tolerance, withdrawal and reinforcement. Its suitable 
pharmacokinetics and generally good tolerability make it a promising potential 
treatment for these conditions.