Addiction to prescription drugs like Vicodin and OxyContin has become a more serious problem in the U.S. than addiction to illegal drugs like cocaine and heroin. The CDC reports that the number of prescription drug overdose deaths in 2011 exceeded the number of deaths from illegal drug overdoses. The magnitude of this problem is putting  increasing pressure on drug makers to find a solution for prescription drug abuse. MediciNova, a San Diego drug manufacturer, is banking on a drug called Ibudilast to help ease recovery from prescription drug addiction. The National Institutes for Drug Abuse (NIDA) is funding clinical trials to determine if the drug can safely be used as a treatment for addiction to methamphetamine and opioid prescription drugs. MediciNova reports that Ibudilast reduces the cravings that can cause relapse during drug treatment. The company is recommending that the…