Marinol is only available with a prescription, according to Drugs.com. Dronabinol is an orally active cannabinoid that is the active ingredient in Marinol. It affects the central nervous system.
Marinol affects appetite, mood, cognition, memory and perception, with reversible effects, explains Drugs.com. The drug takes effect within 30 and 60 minutes, and the effects peak between two and four hours after taking the medication. It may continue to stimulate the appetite for up to 24 hours. AIDS patients take Marinol to reduce weight loss associated with anorexia, and chemotherapy patients take the medication to reduce nausea and vomiting when they have not responded to other antiemetic treatments.