Treatment with amlodipine is well tolerated. In controlled clinical trials comparing amlodipine to placebo, the most common side effects are as follows: Autonomic Nervous System: Flushing. General: Fatigue. Cardiovascular: Edema, palpitation. Central and Peripheral Nervous System: Vertigo, headache, drowsiness. Gastrointestinal: Abdominal pain, nausea.