Which symptom should prompt a client to seek emergency medical assistance while using nitroglycerin?

Chest pain lasting longer than 5 minutes while using nitroglycerin is a critical symptom that necessitates emergency medical assistance. Nitroglycerin is commonly prescribed to relieve angina, but if a patient experiences continued chest pain despite taking their medication, it may indicate that they are experiencing a myocardial infarction or other serious cardiac event. This scenario suggests that the medication is not effectively alleviating the underlying issue, which could lead to complications if not treated immediately.

In this context, lightheadedness might occur due to hypotension (a common side effect of nitroglycerin) and requires monitoring but doesn't necessarily indicate a life-threatening condition. A minor headache is also a common side effect of nitroglycerin and typically does not require urgent intervention. Likewise, slight nausea can occur and may not signify an acute issue. These symptoms do warrant attention, but they do not carry the same level of urgency as prolonged chest pain while on nitroglycerin, which is a critical sign of potential cardiac distress.