Brand Name
Nipride, Nitropress
Class and Category
Chemical class: Cyanonitrosylferrate
Therapeutic class: Antihypertensive, vasodilator
Pregnancy category: C
Indications and Dosages
To treat hypertensive crisis and manage severe heart
failure
I.V. INFUSION
Adults and children. Initial: 0.25 to 0.3
mcg/kg/min, increased gradually every few minutes until blood pressure reaches desired
level. Maintenance: 3 mcg/kg/min (range, 0.25 to 10 mcg/kg/min). Maximum:
10 mcg/kg/min for 10 min.
Route Onset
Peak Duration
I.V. 1–2
min Immediate 1–10 min
Mechanism of Action
May interact with nitrate receptors in vascular smooth-muscle cell
membranes. This action reduces nitroprusside to nitric oxide and then activates
intracellular guanylate cyclase, which increases the cGMP level. Increased cGMP
level may relax vascular smooth muscle by forcing calcium out of muscle cells.
Smooth-muscle relaxation causes arteries and veins to dilate, which reduces
peripheral vascular resistance and blood pressure.
Incompatibilities
Don’t mix nitroprusside with any other drug.
Contraindications
Acute heart failure with decreased peripheral vascular resistance,
congenital optic atrophy, decreased cerebral perfusion, hypersensitivity to
nitroprusside or its components, hypertension from aortic coarctation or AV
shunting, tobacco-induced amblyopia
Interactions
DRUGS
dobutamine: Increased cardiac output, decreased pulmonary
artery wedge pressure
ganglionic blockers, general anesthetics, hypotension-producing
drugs: Increased hypotensive effect
sympathomimetics: Decreased antihypertensive effect
of nitroprusside
Adverse Reactions
CNS: Anxiety, dizziness, headache, increased intracranial pressure,
nervousness, restlessness
CV: Hypotension, tachycardia
ENDO: Hypothyroidism
GI: Abdominal pain, ileus, nausea, vomiting
HEME: Methemoglobinemia
MS: Muscle twitching
SKIN: Diaphoresis, flushing, rash
Other: Infusion site phlebitis
Nursing Considerations
•Obtain baseline vital signs before administering nitroprusside.
WARNING Don’t give drug undiluted. Reconstitute
with 2 ml D5W, and add solution to 250 to 500 ml D5W to produce 200 mcg/ml or
100 mcg/ml, respectively.
• Be aware that solution is stable at room temperature for 24
hours when protected from light. Don’t use reconstituted solution if it
contains particles or is blue, green, red, or darker than faint brown.
• Use an infusion pump. Place opaque cover over infusion container
because drug is metabolized by light. I.V. tubing doesn’t need to be covered.
• Keep patient supine when starting drug or titrating dose up or down.
•Monitor blood pressure continuously with intra-arterial pressure
monitor. Record blood pressure every 5 minutes at start of infusion and every
15 minutes thereafter.
• If patient has severe heart failure, expect to administer an
inotropic drug, such as dopamine or dobutamine, as prescribed.
WARNING For patient who receives prolonged nitroprusside
therapy or shortterm high-dose therapy, watch for evidence of thiocyanate
toxicity (ataxia, blurred vision, delirium, dizziness, dyspnea, headache,
hyperreflexia, loss of consciousness, nausea, tinnitus, vomiting). Toxicity can
cause arrhythmias, metabolic acidosis, severe hypotension, and death.
•Monitor serum thiocyanate level at least every 72 hours; levels
above 100 mcg/ml are associated with toxicity.
WARNING Assess patient for evidence of cyanide
toxicity (absence of reflexes, coma, distant heart sounds, hypotension,
metabolic acidosis, mydriasis, pink skin, shallow respirations, and weak
pulse). If you detect such evidence, discontinue nitroprusside, as ordered, and
give 4 to 6 mg/kg sodium nitrite over 2 to 4 minutes to convert hemoglobin to
methemoglobin. Follow with 150 to 200 mg/kg sodium thiosulfate. Repeat this
regimen at half the original doses after 2 hours, as ordered.
PATIENT TEACHING
•
Advise patient to change position slowly to minimize dizziness from sudden,
severe hypotension