Some high blood pressure medications initially cause drowsiness, dizziness, and lightheadedness. Some even cause fainting on the first dose. The body usually adjusts to the effects of these medications and the side effects disappear. Consuming alcohol during the early phase of antihypertensive treatment could be risky because alcohol can also cause dizziness, drowsiness, and lightheadedness.
Hypertension is the most important preventable risk factor for premature death worldwide. It increases the risk of ischemic heart disease, strokes, peripheral vascular disease, and other cardiovascular diseases, including heart failure, aortic aneurysms, diffuse atherosclerosis, chronic kidney disease, atrial fibrillation, and pulmonary embolism. Hypertension is also a risk factor for cognitive impairment and dementia. Other complications include hypertensive retinopathy and hypertensive nephropathy.
Angiotensin receptor blockers prevent the actions of angiotensin II on the arteries. This means the arteries stay more open and blood pressure is lowered. ARBs can take a few weeks to work. Side effects can include dizziness, muscle cramps, insomnia, and elevated potassium levels. As with ACE inhibitors, women who are pregnant, planning to get pregnant, or breastfeeding should not take ARBs.
Quitting smoking. Visit Smoking and Your Heart and the National Heart, Lung, and Blood Institute’s Your Guide to a Healthy Heart [PDF – 2MB]. Although these resources focus on heart health, they include basic information about how to quit smoking. For free help and support to quit smoking, you can call the National Cancer Institute’s Smoking Quitline at 1-877-44U-QUIT (1-877-448-7848).
Severe high blood pressure is referred to as malignant hypertension, in which the diastolic ("bottom") blood pressure reading is over 140 mmHg. Malignant hypertension is a medical emergency and can cause stroke. Symptoms can include nausea, severe headache, blurred vision, and dizziness. Some people with malignant hypertension may develop kidney failure. They may experience a decrease in urine output and swelling (edema), most pronounced in the lower legs.
Another form of postural hypotension occurs typically in young healthy individuals. After prolonged standing, the individual's heart rate and blood pressure drop, causing dizziness, nausea, and often fainting. In these individuals, the autonomic nervous system wrongly responds to prolonged standing by directing the heart to slow down and the veins to dilate thereby removing blood from circulating in the arteries.
Unlike high blood pressure symptoms, which are poorly defined and often totally absent, low blood pressure symptoms tend to be more upfront and easily recognizable. The development of symptoms is often a warning sign of a potentially serious underlying disorder. Generally speaking, your blood pressure would need to fall pretty dramatically before symptoms develop.