Final answer:
True, morphine is associated with histamine release and can cause itching, vasodilation, and hypotension; hydromorphone has a lower incidence of these side effects.
Step-by-step explanation:
The statement "Hydromorphone is not associated with histamine release but morphine is" is true. Morphine is well-known for triggering the release of histamine, which can lead to various side effects such as itching, vasodilation, and sometimes hypotension. On the other hand, hydromorphone, a semi-synthetic opioid derived from morphine, is associated with lower incidences of histamine release compared to morphine, which makes it a suitable alternative for patients who experience significant histamine-related side effects from morphine.