Concept:
Amlodipine is a calcium channel blocker used mainly in cardiovascular diseases.
Step 1: Hypertension means increased blood pressure.
Step 2: Amlodipine blocks calcium entry into vascular smooth muscle.
Step 3: This causes relaxation of blood vessels.
Step 4: Relaxation of blood vessels reduces peripheral resistance and lowers blood pressure.
Step 5: Therefore, amlodipine is used in hypertension.
\[
\boxed{\text{Hypertension}}
\]