Which medication is NOT a controlled substance?

Bentyl, also known as hyoscyamine, is not classified as a controlled substance. It is an antispasmodic medication that works by relaxing the muscles of the gastrointestinal tract. Its use is generally for the treatment of various gastrointestinal disorders, including irritable bowel syndrome. The classification of controlled substances is typically reserved for drugs that have a high potential for abuse or dependence, which does not apply to Bentyl.

In contrast, the other medications listed are controlled substances. Methylphenidate hydrochloride is a stimulant often used to treat ADHD and narcolepsy, categorized as a Schedule II drug due to its potential for abuse. Hydroxyzine pamoate is an antihistamine useful for anxiety and sedation but is sometimes regulated in certain situations due to potential misuse. Glimepiride is an antidiabetic medication that requires careful management due to its effects on blood sugar levels, though it is not a controlled substance, it is often monitored in practice.

Thus, understanding the classification and use of each drug helps clarify why Bentyl stands out as a non-controlled substance.