Which adverse effect is least likely associated with Dopamine(D2) Receptor antagonists?

Dopamine (D2) receptor antagonists are primarily used in the treatment of conditions such as nausea, vomiting, and certain psychiatric disorders. These medications work by blocking dopamine receptors in the central nervous system and, in some cases, the gastrointestinal tract.

When considering the possible adverse effects of dopamine receptor antagonists, weight loss is least likely to be associated with their use. These medications may lead to side effects such as CNS depression, where sedation or lethargy can occur due to their action in the brain. They can also prompt increased gastrointestinal activity, which may contribute to diarrhea as a potential side effect. As for gastric emptying, these drugs tend to enhance motility in the gastrointestinal tract, leading to a quicker emptying process.

In contrast, weight loss is typically not a common result of the use of D2 receptor antagonists. Instead, these drugs may cause weight gain, particularly when used over longer periods, as they can alter metabolism and appetite regulation. Therefore, the least likely adverse effect associated with dopamine (D2) receptor antagonists is weight loss.