Which of the following is an undesirable effect of nonsteroidal anti-inflammatory drugs?

Urinary retention is not typically linked to NSAID use. This condition is more commonly associated with medications affecting the urinary tract or neurological conditions rather than the gastrointestinal side effects of NSAIDs. Therefore, it does not represent a common undesirable effect of NSAIDs.

Pyrexia, or fever, is generally not considered an undesirable effect of NSAIDs. In fact, NSAIDs are often used to reduce fever as part of their anti-inflammatory properties. Thus, while NSAIDs may sometimes cause other side effects, pyrexia is not one of them.

Constipation is not a widely recognized adverse effect of NSAIDs. While some medications can lead to constipation, NSAIDs primarily affect the gastrointestinal system in the opposite direction, with more common effects being dyspepsia or gastrointestinal irritation. Therefore, constipation does not align closely with the typical undesirable effects of NSAIDs.