The medical marijuana drug Sativex, which could be approved in the United States in the coming years as a treatment for pain relief, has little potential for abuse, experts say. The British pharmaceutical company GW Pharmaceuticals is currently testing the drug, which is delivered as a mouth spray and called Sativex, in clinical trials. The company plans to seek U.S. Food and Drug Administration approval for the drug as a treatment for cancer pain when the trials are completed.