Final answer:
For a patient taking lisinopril 10 mg daily after an MI, the most appropriate instruction is to change positions slowly to avoid dizziness or fainting, a side effect known as orthostatic hypotension.
Step-by-step explanation:
The most appropriate instruction for a patient being discharged after a myocardial infarction (MI) and taking lisinopril 10 mg daily is to change positions slowly when going from lying to sitting. Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor used in the treatment of hypertension and heart failure, which can lead to side effects like dizziness or lightheadedness upon sudden changes in position, known as orthostatic hypotension.
Therefore, it is important for patients to move slowly to avoid potential falls or fainting. Instructions like avoiding leg crossing may be given to patients for other conditions, reducing sodium intake is a general dietary advice for heart health, and weighing themselves regularly is important mainly for patients on medications that can cause rapid weight changes. However, regarding the immediate concern with lisinopril, changing positions gradually is the most directly relevant precaution.