Final answer:
Vicodin is the drug among the ones listed that is classified as a Schedule II substance, due to its high potential for abuse and risk of severe psychological or physical dependence. Codeine in cough syrup is typically not Schedule II, and ketamine is a Schedule III drug.
Step-by-step explanation:
Among the substances listed, Vicodin is classified as a Schedule II drug. Schedule II drugs are defined as substances that have a high potential for abuse which may lead to severe psychological or physical dependence. Examples of Schedule II drugs include Vicodin, methadone, oxycodone, fentanyl, amphetamine, and morphine. Vicodin, which contains hydrocodone and acetaminophen, is used to alleviate moderate to severe pain but is known for its high potential for abuse and dependency.
Codeine is another opioid that is frequently prescribed for minor pain relief and as an ingredient in cough syrup. Although it has a relatively lower potency compared to other opioids, it still has abuse potential. However, codeine in cough syrup with low dosage quantities is typically classified as Schedule III or V, depending on concentration and formulation, and therefore, a cough syrup with codeine is not a Schedule II substance.
Amphetamine, which is found in medications used to treat attention deficit hyperactivity disorder (ADHD) and narcolepsy, is also a Schedule II drug due to its high potential for abuse and dependency. It is noteworthy that while ketamine has abuse potential, it is classified as a Schedule III substance due to its accepted medical uses and lower potential for abuse relative to Schedule II substances.