Final answer:
Diltiazem is used to treat high blood pressure and Prinzmetal's angina by relaxing and widening blood vessels, allowing more blood and oxygen to reach the heart.
Step-by-step explanation:
Diltiazem is used to treat high blood pressure, chest pain (angina) caused by reduced blood supply to the heart muscle, and some abnormal heart rhythms.
In the case of Prinzmetal's angina, diltiazem helps to relieve chest pain by relaxing and widening the blood vessels, allowing more blood and oxygen to reach the heart.
It also helps to reduce the workload on the heart, which can be beneficial in managing hypertension.