Many of these drugs combat the side-effects of opioid analgesics, an added bonus. For example, antihistamines including orphenadrine combat the release of histamine caused by many opioids. Stimulants such as methylphenidate, caffeine, ephedrine, dextroamphetamine, methamphetamine, and cocaine work against heavy sedation and may elevate mood in distressed patients as do the antidepressants.[citation needed] The use of medicinal cannabis remains a debated issue.