Dizziness, flushing, weakness, drowsiness, fatigue; nausea, vomiting; dyspnoea, sensory disturbance including paraesthesia & hypoaesthesia; pain or sensations of heaviness, heat/cold, pressure, or tightness; transient increases in BP; hypotension, bradycardia/tachycardia, palpitations, Raynaud's syndrome, ischaemic colitis; visual disturbances; medication-overuse headache. Occasionally, minor disturbances in liver function. Hypersensitivity reactions ranging from skin rashes to, more rarely, anaphylaxis; GI tract & resp system effects; ischaemic colitis, mesenteric ischaemia, oesophageal constriction or throat tightness. Pain or chest tightness or anginal pain; cerebral vasospasm.