What is a common side effect of Amlodipine at initiation of therapy?

Amlodipine is a calcium channel blocker commonly used to treat hypertension and angina. One of the most frequently observed side effects, especially at the initiation of therapy, is dizziness. This occurs because amlodipine can lead to vasodilation, causing a decrease in blood pressure. When a patient starts this medication, their body might not immediately adjust to these changes in blood pressure, resulting in feelings of dizziness. This symptom is typically transient as the body adapts to the medication over time.

The other options, while they may be associated with various medications, are not generally recognized as common side effects of amlodipine during the initiation of therapy. Severe headache might be linked to blood pressure fluctuations but is not specific to amlodipine. Rash and insomnia are not typical initial side effects of this drug, further supporting that dizziness is the most relevant choice in this context.