Final answer:
Patients with chronic alcoholism on nitrates should be warned about severe hypotension and potential cardiovascular collapse due to the interaction between alcohol and nitrates, which can significantly lower blood pressure.
Step-by-step explanation:
A patient with chronic alcoholism who has started on nitrates should be warned about the possibility of severe hypotension and cardiovascular collapse. The interaction between alcohol and nitrates can potentiate the blood-vessel dilating effect of nitrates leading to dangerously low blood pressure and increased risk of cardiovascular collapse.
If a patient who has consumed alcohol starts experiencing symptoms such as severe dizziness, fainting or an abnormally slow heartbeat, they should seek immediate medical help. It is crucial for health care professionals to properly educate patients on the risks of combining alcohol with medications like nitrates.