Class: Vasodilator antihypertensive drugs
- Nitroprusside sodium :
Trade names: Nitropress
Pregnancy: (Category C)
Its mechanism of action appears to be liberation of nitric oxide (NO), converting Hemoglobin to cyanomethaemaglobin. Nitroprusside also releases cyanide ions which are converted in the liver to thiocyanate by the enzyme rhodanase, a reaction which requires a sulfur donor such as thiosulfate. Thiocyanate is then excreted by the kidney. In the absence of sufficient thiosulfate, cyanide ions can quickly reach toxic levels.
The half-life of nitroprusside is less than 10 minutes although thiocyanate has an excretion half life of several days. The duration of treatment should not exceed 72 hours and thiocyanate plasma concentrations should be monitored.
immediate reduction of blood pressure of patients in hypertensive crises.
producing controlled hypotension in order to reduce bleeding during surgery.
treatment of acute congestive heart failure.
· Hypertensive crisis, by intravenous infusion, initially 0.5–1.5 micrograms/kg/minute, then increased in steps of 0.5 micrograms /kg/minute every 5 minutes within range 0.5–8 micrograms/kg/minute (lower doses in patients already receiving other antihypertensives); stop if response unsatisfactory with max. dose in 10 minutes
· Maintenance of blood pressure at 30–40% lower than pretreatment diastolic blood pressure, 20–400 micrograms/minute (lower doses for patients being treated with other antihypertensives)
[IMG]file:///C:/DOCUME~1/4949~1/LOCALS~1/Temp/msohtmlclip1/01/clip_image001.gif[/IMG] should not be used in the treatment of compensatory hypertension, where the primary homodynamic lesion is aortic coarctation or arteriovenous shunting.
[IMG]file:///C:/DOCUME~1/4949~1/LOCALS~1/Temp/msohtmlclip1/01/clip_image001.gif[/IMG] should not be used to produce hypotension during surgery in patients with known inadequate cerebral circulation, or in moribund patients (A.S.A. Class 5E) coming to emergency surgery.
[IMG]file:///C:/DOCUME~1/4949~1/LOCALS~1/Temp/msohtmlclip1/01/clip_image001.gif[/IMG] Patients with congenital (Leber's) optic atrophy or with tobacco amblyopia have unusually high cyanide! thiocyanate ratios.
[IMG]file:///C:/DOCUME~1/4949~1/LOCALS~1/Temp/msohtmlclip1/01/clip_image001.gif[/IMG] Sodium nitroprusside should not be used for the treatment of acute congestive heart failure associated with reduced peripheral vascular resistance such as high-output heart failure that may be seen in endotoxic sepsis.
allergic reaction: hives; difficulty breathing; swelling of face, lips, tongue, or throat.
feeling extremely light-headed, even while lying down;
confusion, ringing in your ears;
fainting, breathing that stops;
gasping or struggling to breathe;
dizziness with nausea and vomiting, confusion, rapid breathing, and seizure;
tremors, chills, bowel or bladder urgency;
fast, slow, or uneven heart rate;
easy bruising or bleeding; or muscle pain or weakness, numb or cold feeling in your arms and legs.
This drug can cause very large decreases in blood pressure so proper monitoring, serious injury or death could result.
Nitroprusside, especially in larger-than-recommended doses, might cause cyanide poisoning. Therefore, be sure not to exceed the recommended dose, instructed by the doctors especially if the patient has kidney problems.