In response to the patient's query about how to know whether drugs are safe, the nurse explains that all medications undergo rigorous scientific testing controlled by what organization?

Choice A rationale

Working with animals is typically done in preclinical trials before phase I studies in humans and is not part of phase III drug evaluation studies.

Choice B rationale

Conducting research to determine the effectiveness of the drug is part of phase II studies. Phase III studies focus more on confirming effectiveness, monitoring side effects, and comparing it to commonly used treatments.

Choice C rationale

Monitoring and observing patients closely for adverse effects is a key responsibility in phase III drug evaluation studies. These studies involve a larger patient population to gather comprehensive safety and efficacy data.

Choice D rationale

Choosing appropriate patients to be involved in the study is primarily the responsibility of researchers and clinicians during the earlier phases of drug development, such as phase I and phase II studies.

Choice A rationale

Sumatriptan does not cause vasodilation of peripheral blood vessels. Instead, it has vasoconstrictive properties.

Choice B rationale

Sumatriptan does not depress pain response in the central nervous system. Its primary action is on the cranial blood vessels.

Choice C rationale

Sumatriptan is a selective serotonin receptor agonist that causes vasoconstriction of cranial blood vessels, relieving migraine headaches.

Choice D rationale

Sumatriptan does not bind to acetylcholine receptors or prevent nerve transmission. It specifically targets serotonin receptors in cranial blood vessels.