Encephalopathy refers to altered brain function. When this malfunction is related to severely elevated blood pressure, it is termed hypertensive encephalopathy. Symptoms include headache, confusion, altered level of consciousness, seizures, visual changes and coma. It is usually associated with a blood pressure at or above 180 over 120 mm of mercury, and defines a hypertensive emergency. Intravenous, or IV, drugs are indicated in an attempt to lower blood pressure in order to limit or prevent brain damage.
Sodium Nitroprusside
Sodium nitroprusside, or simply nitroprusside, is a drug that acts to dilate both arteries and veins, says the Merck Manual for Healthcare Professionals. The drug is metabolized to cyanide and nitric oxide, so must be administered carefully to prevent cyanide toxicity. Nausea, vomiting, muscle twitching and sweating are the most common side effects. All containers and tubing holding the drug must be opaque, as light weakens the medicine.
Nicardipine
This drug is a calcium channel blocker that dilates blood vessels. Its beneficial effect on blood pressure makes it an effective treatment for hypertensive encephalopathy. Cleveland Clinic lists headache, flushing, nausea, vomiting and increased heart rate as side effects.
Fenoldopam
Fenoldopam is a medicine that acts via dopamine to produce blood vessel dilation in the kidneys and the periphery, says the Merck Manual for Healthcare Professionals. Its rapid onset of action makes it useful in the treatment of hypertensive emergencies such as encephalopathy. It should be avoided in those with glaucoma due to its effect on eye pressure. Other side effects of fenoldopam include increased heart rate, headache, dizziness and flushing.
Labetalol
Labetalol is an alpha and beta receptor blocker that acts to decrease blood pressure and heart rate, according to information on Drugs.com. It may slow the heart rate too much, or cause a condition called heart block which may lead to a slow, irregular heart rate. This drug should not be used to treat asthmatics with hypertensive encephalopathy, as it may worsen that condition by causing spasm in the airways.
Nitroglycerin
Nitroglycerin, sometimes called nitro, acts to open up veins more than arteries. It is especially useful in those suffering from hypertensive encephalopathy with concurrent coronary artery disease, as it increases blood flow to the heart, says the Merck Manual for Healthcare Professionals. Nitroglycerin loses its effectiveness if used continuously over time due to tolerance. Headache is a common side effect. Increased heart rate, nausea, vomiting and heart palpitations are also possible.
