Vasodilators Flashcards
Nitroglycerin: Class
Peripheral Vasodilator
venous dilation > arterial dilation
Nitroglycerin: Use
Myocardial Ischemia
Coronary Vasospasm
HTN
Ventricular failure
Controlled Hypotension
Nitroglycerin: Mechanism of Action
As Nitroglycerin is metabolized, releases nitric oxide and cyanide.
Nitric oxide activates guanylyl cyclase which synthesizes cGMP, decreases intracellular Calcium. -> Smooth muscle dilation
Nitroglycerin: Dose
IV Infusion: 5 - 100 mcg/min
SL: 0.4 mg
Nitroglycerin: Pharmacokinetics
Absorption: IV, SL, Transdermal
Onset: 2 minutes
Duration of Action: 5 minutes
Metabolism: Rapid reductive hydrolysis in the liver and blood by glutathione-organic nitrate reductase
Elimination: Renal
Nitroglycerin: Contraindictions
Patients with:
Aortic Stenosis
Hypertrophic cardiomyopathy
Increased ICP
Hypotension
Heart Failure
Nitroglycerin: Considerations
Nitrate byproduct can convert hemoglobin to methemoglobin
Headache
Tachycardia
Tolerance can develop with prolonged use
Nitroprusside: Class
Direct peripheral arterial vasodilator
relaxes both arterial and venous smooth muscle
Nitroprusside: Use
Antihypertensive
Nitroprusside: Mechanism of Action
Nitroprusside is metabolized into nitric oxide and cyanide.
Nitric Oxide activates guanylyl cyclase which synthesizes cGMP, decreases intracellular calcium, which causes smooth muscle dilation
Nitroprusside: Dose
Infusion: 0.3 - 10 mcg/kg/min
Nitroprusside: Pharmacokinetics
Absorption: IV
Onset: 1 minute
Duration of Action: 3 - 5 minutes
Metabolism: Iron electron of oxyhemoglobin binds to NTP. Gets broken down into cyanmethemoglobin and cyanide
Elimination: Renal
Nitroprusside: Contraindications
Aortic Stenosis
Hypertrophic Cardiomyopathy
Increased ICP
Renal Failure (build up Thiocyanate)
Nitroprusside: Considerations
Can cause tachycardia, headache, and bronchodilation
Risk for Intracoronary steal
Risk for Cyanide Toxicity
May decrease lung perfusion
Need to protect from light
Hydralazine: Class
Direct acting Arterial vasodilator
Hydralazine: Use
Treat HTN
Hydralazine: Mechanism of Action
Activate guanylate cyclase to increase cGMP
Hydralazine: Dose
Bolus: 2.5 - 20 mg
Hydralazine: Pharmacokinetics
Absorption: IV, PO
Onset: 15 minutes
Duration of Action: 2 - 4 hours
Metabolism: Hepatic
Elimination: Renal
Hydralazine: Contraindications
Patients with:
Aortic stenosis
Hypertrophic cardiomyopathy
increased ICP
Hypotension
Heart Failure
Hydralazine: Considerations
Can cause reflex tachycardia
Nicardipine: Class
Calcium Channel Blocker
Nicardipine: Use
Treatment of:
Angina
HTN
Cerebral Vasospasm
Controlled Hypotension
Nicardipine: Mechanism of Action
Depress electrical impulses in the SA and AV nodes by blocking the influx of Calcium ions
Nicardipine: Dose
Infusion:
5 mg/hr increase by 2.5mg q 15 minutes.
MAX dose 15 mg/hr
Nicardipine: Pharmacokinetics
Absorption: IV
Onset: 1 minute
Duration of Action: 3 hours
Metabolism: Hepatic
Elimination: Renal
Nicardipine: Contraindications
Acute MI
Heart Failure
Bradycardia
Hypotension
Patient taking Dantrolene
Nicardipine: Considerations
May cause reflex tachycardia
