What is a common adverse effect of opioid antagonists?

Opioid antagonists, such as naloxone and naltrexone, are primarily used to reverse the effects of opioids, particularly in cases of overdose. While they are effective in rapidly alleviating the life-threatening effects of excessive opioid use, they can also precipitate withdrawal symptoms in individuals dependent on opioids.

Abdominal pain, often experienced as cramping or discomfort, is a common adverse effect associated with opioid antagonists. This discomfort is typically a result of opioid withdrawal, which can cause gastrointestinal distress among other symptoms. The mechanism behind this is related to the opioid system's role in pain modulation and gastrointestinal function; when this system is suddenly reversed or blocked by an antagonist, it can lead to a quick change that results in pain and discomfort.

In contrast, adverse effects like constipation, drowsiness, and hypertension are usually associated with opioid agonists rather than antagonists. Opioids often cause constipation due to their action on the gut and can lead to sedation and drowsiness because of their central nervous system effects. Hypertension is not a common concern related to opioid antagonism but rather to other drug interactions or patient-specific conditions.