Which of the following would most likely indicate the need for an immediate medical review of a medication?

Severe allergic reactions are critical and can pose immediate threats to a person's health. Such reactions, which may manifest as difficulty breathing, swelling of the face or throat, hives, or anaphylaxis, necessitate urgent medical attention. The body's response can be swift and severe, requiring quick intervention to prevent further complications or even mortality.

In contrast, while mild headaches, routine nausea, and infrequent dizziness can be uncomfortable and warrant attention, they typically do not present the same immediate danger as severe allergic reactions. These symptoms may indicate less serious issues that could be managed with a review over time or adjustments to a treatment plan, whereas an allergic reaction requires prompt evaluation and intervention to ensure the patient's safety and well-being.