Which medication is specifically indicated for diarrhea and requires a script?

Diphenoxylate/Atropine is specifically indicated for the treatment of diarrhea and is classified as a prescription medication. This combination medication works by slowing down gut motility, which helps to reduce the frequency of bowel movements and improve overall stool consistency. The inclusion of atropine is intended to discourage misuse, as the drug has potential for abuse due to its effects on the central nervous system if taken excessively.

Loperamide, although effective for diarrhea, is available over the counter and does not require a prescription. Bismuth subsalicylate is another over-the-counter option used for symptomatic relief of diarrhea and is also not prescription-required. Ranitidine, on the other hand, is indicated for conditions related to excess stomach acid, such as GERD, rather than diarrhea. Therefore, Diphenoxylate/Atropine stands out as the correct choice due to its specific prescription requirement and therapeutic indication for diarrhea treatment.