Nitroprusside

Question 1

Alternate Names

Answer 1

Nipride, Nitropress

Question 2

Drug Class

Answer 2

Pharm: vasodilator
Therapeutic: Antihypertensive, management of severe CHF, management of pulmonary hypertension, produced controlled hypotension to reduce bleeding during surgery

Question 3

Pharmacodynamics

Answer 3

Acts “directly” on vascular SM to cause dilation of both veins and arterioles; metabolized to release CN- and NO -> activates guanylate cyclase -> production of cGMP from GTP -> leads to vasodilation -> cGMP then hydorlyzed to GMP by PDE

CN- + NO -> cGMP -> vasodilation -> GMP

Question 4

Pharmacokinetics

Answer 4

Only route is IV; rapid onset (minutes) and cessation (minutes), thereby allowing minute-by-minute titration; CN- metabolite is converted to SCN in liver, then excreted in urine, must be given by continuous infusion

Question 5

Toxicity

Answer 5

Excessive hypotension; accumulation of CN- and thiocyanate; headache; decreased blood flow to brain

Question 6

Interactions

Answer 6

Additive effects with most other antihypertensives

Question 7

Special Considerations

Answer 7

Monitor patient very closely - must be in ICU with arterial line; avoid high infusion rates or prolonged infusions, to prevent accumulation of CN-; use with caution in patients with increased intracranial pressure

Question 8

Indications and Dose / Route

Answer 8

For treatment of hypertensive crisis, given as IV infusion at 0.3 - 10 mcg/kg per minute

Question 9

Monitoring

Answer 9

BP, HR, metabolic acidosis, most often requires arterial line