Final answer:
Thiazide diuretics are the best-studied and most recommended first-line medication for treating hypertension in older patients without other compelling medical indications.
Step-by-step explanation:
The best-studied and most recommended first-line medication for treating hypertension in older patients without other compelling medical indications is thiazide diuretics. Thiazide diuretics help lower blood pressure by reducing the amount of fluid in the body and relaxing the blood vessels. They are considered safe and effective for older patients and have been shown to reduce the risk of cardiovascular events.