What causes lightheadedness and dizziness?

Lots of things!: Sorting out the significance of those symptoms depends on accompanied circumstances (precipitating events, duration, palpitations), objective findings (abnormal cardiac or neurologic exam), age (younger, older), etc. Often these may be relatively benign (if younger patient and not objective abnormalities), but may also be a harbinger of more serious underlying conditions. Talk to your doctor.

Vertigo: If drug side effect is excluded, far more common cause of feeling of one or more of lightheadedness, spinning, tilting, falling, losing balance is vertigo. Diagnostic difficulty occurs when symptoms are mild. Expensive cardiac work up is often done. Many a times some cardiac abnormality e.G bradycardia or severe carotid stenosis is found and treated but dizziness persists until vertigo is treated.