There are numerous causes of dizziness. A common cause is getting up too quickly from a sitting position. This is called orthostatic hypotension, where blood pressure drops rapidly as a person stands up. Medications can also cause dizziness. They include such drugs as barbiturates, antihistamines, diuretics, and the antibiotics streptomycin, neomycin, and gentamicin.
Arteriosclerosis is another cause of dizziness.
This is when a decreased amount of blood gets to the brain due to narrowing of the arteries. Infections of the inner ear can cause severe dizziness and vertigo, that is, the feeling that you are spinning around in space, or the environment is spinning around in space. This symptom can be very disturbing. Other causes of dizziness include motion sickness, excessive alcohol intake, and damage to the inner ear. Fortunately, brain tumors are a rare cause of dizziness.