Nitroprusside

INTRODUCTION

Indications

Hypertensive crises. Controlled hypotension during anesthesia. Cardiac pump failure or cardiogenic shock (alone or with dopamine).

Action

Produces peripheral vasodilation by a direct action on venous and arteriolar smooth muscle. Therapeutic Effects: Rapid lowering of blood pressure. ↓ cardiac preload and afterload.

Adverse Reactions/Side Effects

CNS: dizziness, headache, restlessness. EENT: blurred vision, tinnitus. CV: dyspnea, hypotension, palpitations. GI: abdominal pain, nausea, vomiting. F and E: acidosis. Local: phlebitis at IV site. Misc: CYANIDE TOXICITY, thiocyanate toxicity.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Watch for signs of cyanide or thiocyanate toxicity, including weakness, malaise, confusion, combativeness, giddiness, vertigo, shortness of breath, apnea, seizures, and coma. Report these signs to the physician or nursing staff immediately.

• Assess blood pressure (BP), and determine if BP is maintained in the normal range (See Appendix F). Be alert for any residual hypotension following surgery.

• Monitor any cardiac palpitations or difficult, labored breathing. Report prolonged or severe cardiac or pulmonary symptoms.

• Monitor signs of acidosis, including headache, lethargy, confusion, and rapid breathing. Notify physician or nursing staff immediately if these signs occur.

• Assess dizziness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician and nursing staff, and caution the patient and family/caregivers to guard against falls and trauma.

• Assess IV site during and after IV administration, and report signs of phlebitis (local pain, swelling, inflammation).

Interventions

• Avoid physical therapy interventions that cause systemic vasodilation (large whirlpool, Hubbard tank) until drug effects have been completely resolved. Additive effects of this drug and the intervention may cause a dangerous fall in blood pressure.

• To minimize orthostatic hypotension, patient should move slowly when assuming a more upright position.

Patient/Client-Related Instruction

• Counsel patients about additional interventions to help with the long-term control of BP and cardiac dysfunction, including regular exercise, weight loss, sodium restriction, stress reduction, moderation of alcohol consumption, and smoking cessation.

• Instruct patient or family/caregivers to report residual side effects such as severe or prolonged headache, restlessness, blurred vision, ringing/buzzing in the ears (tinnitus), or GI problems (nausea, vomiting, abdominal pain).

Pharmacokinetics

Absorption: IV administration results in complete bioavailability.

Distribution: Unknown.

Metabolism and Excretion: Rapidly metabolized in RBCs and tissues to cyanide and subsequently by the liver to thiocyanate.

Half-life: 2 min.