## **Core Concept**
The question tests the understanding of pharmacological management of biliary colic and the potential effects of certain medications on biliary smooth muscle. Biliary colic is typically caused by a gallstone obstructing the cystic duct or common bile duct. The management involves analgesia and sometimes spasmolytics.

## **Why the Correct Answer is Right**
The correct answer, **D. Morphine**, can cause worsening of biliary colic pain due to its effect on the sphincter of Oddi. Morphine can cause contraction of the sphincter of Oddi, increasing the pressure within the biliary system, which can worsen the pain in the setting of a obstructing gallstone. This is a critical consideration in the acute management of biliary colic.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Atropine is an anticholinergic agent that can cause relaxation of smooth muscles, including those in the gastrointestinal tract. It is unlikely to worsen biliary colic.
- **Option B:** Hyoscine butylbromide (Buscopan) is an antispasmodic drug used to relieve smooth muscle spasms. It would likely help, not worsen, biliary colic.
- **Option C:** Diclofenac, a NSAID, is commonly used to manage pain in biliary colic as it reduces inflammation and provides analgesia. It would not worsen the pain.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while morphine is a potent analgesic, its use in biliary colic can be counterproductive due to its effect on the sphincter of Oddi. For acute biliary pain, NSAIDs like diclofenac are often recommended as first-line analgesics.

## **Correct Answer:** D. Morphine