Sodium Nitroprusside for Hypertension Treatment

Sodium nitroprusside is a powerful anti-hypertension medicine that is only used in certain situations when blood pressure must be immediately and dramatically reduced. For example, patients who are experiencing a hypertensive emergency or very high blood pressure following heart or blood vessel surgery may be given sodium nitroprusside, which has a trade name of Nitropress.

In addition to treating hypertension, nitroprusside is used to treat other conditions such as congestive heart failure and also to maintain low blood pressure during certain surgeries. 

Because it can only be administered intravenously, the use of sodium nitroprusside is restricted to the hospital setting. In addition, sodium nitroprusside can cause large and rapid blood pressure decreases that require careful monitoring. 

Sodium nitroprusside belongs to a class of drugs known as NO-releasing agents because it works by releasing nitric oxide. Like all other drugs in that class, sodium nitroprusside works by relaxing blood vessels. Once in the body, sodium nitroprusside is quickly broken down into nitric oxide, a powerful vasodilator. This nitric oxide works as a vasodilator, causing the muscles surrounding blood vessels to relax, allowing the blood vessels themselves to expand. As the blood vessels expand, blood pressure drops.

The breakdown of sodium nitroprusside to nitric oxide happens very quickly, so there is virtually no delay between administration of the drug and blood pressure reduction. Along with its blood pressure-reducing actions, sodium nitroprusside also alters the pattern of blood flow through the vessels that feed the heart, making it useful in the treatment of patients with heart problems.

Several nitrate-based drugs are used for the treatment of high blood pressure and heart problems. Two common nitrates are isosorbide dinitrate and nitroglycerin. All of the nitrate drugs can be used to treat heart problems, and some, like nitroglycerin, are used almost exclusively for that purpose.

The most serious potential side effect of sodium nitroprusside is cyanide poisoning. The conversion of sodium nitroprusside to nitric oxide produces cyanide as a byproduct. In small amounts, this cyanide is managed by the liver, which changes it into a less toxic chemical that is quickly excreted in the urine. In cases of long-term use, or if too much is used at one time, the cyanide can overwhelm the liver and lead to cyanide poisoning. For that reason, administration should be discontinued if blood pressure is not properly controlled after 10 minutes at the maximum dosage. Warning signs include:

• Confusion
• Nausea
• Fatigue

The primary treatment is simply to stop the sodium nitroprusside and give supportive care until the body eliminates the cyanide.

Only you and your doctor can decide on a proper medication for treatment of high blood pressure. Be sure to notify your doctor if you are pregnant or breastfeeding, and to supply the names of any other medicines and/or supplements you are taking. Remember to include over-the-counter medicines, like aspirin or Advil (ibuprofen), and herbal/natural supplements.