A client arrives to the emergency department with chest pain after taking sildenafil. Based on the client's history, which medication should the nurse withhold?

A. Morphine: Morphine is used to relieve chest pain and anxiety in acute coronary syndromes. It acts as a vasodilator and analgesic, and there are no direct contraindications with recent sildenafil use, although blood pressure should still be monitored. B. Nitroglycerin: Nitroglycerin is absolutely contraindicated in clients who have taken sildenafil within the past 24–48 hours. Both drugs are vasodilators, and their combination can lead to severe, life-threatening hypotension due to additive effects on vascular smooth muscle relaxation. C. Aspirin: Aspirin is recommended in acute chest pain cases as it reduces platelet aggregation and helps prevent clot extension. It has no interaction with sildenafil and should not be withheld when myocardial ischemia is suspected. D. Heparin: Heparin is an anticoagulant used in suspected myocardial infarction to prevent further clot formation. It does not have any adverse interactions with sildenafil and remains safe and beneficial in this context.