Yes, it is possible for certain medications, such as proton pump inhibitors, to lead to a decrease in magnesium levels in the blood when used long-term. It is important for patients taking these medications, and others that can affect magnesium levels, to be monitored regularly depending on their individual health conditions. While these medications are not automatically contraindicated for people with heart conditions, it is wise to regularly reassess the need for taking them to avoid unnecessary treatments or unwanted side effects. Regular monitoring and communication with healthcare providers can help ensure safe and effective medication use.