Hypertension (high blood pressure) can be caused by using a chemical substance, drug, or medication. It can also be caused by stopping a drug or medication. See also high blood pressure.

Blood pressure is determined by the amount of blood that is pumped by the heart, the pumping power of the heart, the condition of the heart valves, and the size and condition of the arteries. Many other factors can also affect blood pressure, including:

• The volume of water in the body
• Foods eaten, weight, and other body-related variables
• Condition of the kidneys, nervous system, or blood vessels
• Levels of various hormones in the body

There are several types of high blood pressure. Essential hypertension has no identifiable cause. Secondary hypertension occurs because of another disorder. Drug-induced hypertension is a form of secondary hypertension caused by a response to medication.

Drugs that can cause hypertension include:

• Alcohol, amphetamines, ecstasy (MDMA and derivatives), and cocaine
• Corticosteroids
• Estrogens (including birth control pills) and other hormones
• Migraine medications
• Cyclosporine
• Erythropoietin (used to correct anemia related to chronic diseases -- such as kidney failure, cancer, and HIV)
• Nasal decongestants
• Many over-the-counter medications such as cough/cold medications and medications for asthma -- particularly when the cough/cold medicine is taken with certain antidepressants like tranylcypromine or tricyclics
• High blood pressure medications (such as clonidine) when a person stops taking them -- particularly if the medication is not tapered off (called rebound hypertension)

Headache is an occasional symptom. If the hypertension is severe, the following symptoms can occur:

• Tiredness
• Confusion
• Vision changes
• Nausea and vomiting
• Anxiety
• Excessive perspiration
• Pale skin or redness
• Muscle tremors
• Chest pain

Note: Hypertension usually shows no symptoms.

The health care provider will ask questions regarding the use of drugs which are known to affect blood pressure measurement.

Blood pressure measurements, repeated over time, are used to confirm the diagnosis. Blood pressure that is consistently elevated is considered hypertension.

Two factors determine blood pressure measurements. Systolic blood pressure is the "top" number and is a measurement of the pressure in the blood vessels when the heart beats. Diastolic blood pressure is the "bottom" number which reflects the pressure in blood vessels when the heart is at rest. A consistent rate of more than 140 mm Hg systolic and more than 90 mm Hg diastolic is considered high blood pressure.

Tests to determine the cause of the problem may include blood tests to determine the levels of suspect medications.