Stable coronary artery disease and aspirin 75 mg alone are not a contraindication to acetazolamide. A 60-year-old whose CAD event/intervention was 10 years ago may usually travel to altitude if he is clinically stable, has good exercise tolerance, and has no current angina, heart failure, significant arrhythmia, or recent cardiac event.

However, he should have a pre-travel review with his cardiologist or travel-medicine clinician, particularly if the sleeping altitude will be above 2,500 m or ascent is rapid. The CDC high-altitude guidance advises people with CAD to obtain advice from a clinician familiar with high-altitude travel before departure.

If appropriate after review, common acute mountain sickness prophylaxis is:

There is no important direct interaction with low-dose aspirin. Before prescribing, check for:

He should not rely on acetazolamide in place of a gradual ascent. Sleep no higher than about 500 m more per night once above 3,000 m where feasible, with rest/acclimatization days. CDC advice on ascent and prophylaxis supports this approach.

Do not travel until assessed if he has exertional chest pain, worsening breathlessness, fainting, palpitations, reduced exercise capacity, uncontrolled blood pressure, or a recent change in cardiac status. At altitude, chest pain, severe breathlessness at rest, confusion, poor coordination, or persistent worsening headache/vomiting requires stopping ascent, descending, oxygen if available, and urgent medical assessment.