Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
Pharmacologic class: Sympathomimetic
Therapeutic class: Alpha- and beta-adrenergic agonist, cardiac stimulant, vasopressor
Pregnancy risk category C
FDA Box Warning
If extravasation occurs, infiltrate area promptly with 10 to 15 ml of saline solution containing 5 to 10 mg phentolamine to prevent sloughing and necrosis. Use syringe with fine hypodermic needle, and infiltrate solution liberally throughout area. Give phentolamine as soon as possible; its sympathetic blockade causes immediate local hyperemic changes if area is infiltrated within 12 hours.
Stimulates beta1 and alpha1 receptors in sympathetic nervous system, causing vasoconstriction, increased blood pressure, enhanced contractility, and decreased heart rate
Injection: 1 mg/ml
Indications and dosages
➣ Severe hypotension
Adults: 8 to 12 mcg/minute I.V.; then titrate based on blood pressure response. For maintenance, 2 to 4 mcg/minute.
• Concurrent cyclopropane or halo-thane anesthesia
• Hypotension caused by blood volume deficit (except in emergencies until blood volume replacement is completed), profound hypoxia or hypercarbia
• Mesenteric or peripheral vascular thrombosis
Use cautiously in:
• sulfite sensitivity (some products), especially in asthmatic patients
• arterial embolism, cardiac disease, peripheral vascular disease, hypertension, hyperthyroidism
• patients receiving MAO inhibitors or tricyclic antidepressants concurrently
• elderly patients
• pregnant or breastfeeding patients
• children (safety and efficacy not established).
• Mix with dextrose 5% in water or dextrose 5% in normal saline solution.
• Inspect solution to make sure it's clear and colorless. Don't infuse if it's brown or pink.
• Administer through infusion pump. Titrate infusion rate to achieve and maintain low-normal systolic blood pressure (80 to 100 mm Hg).
• Continue infusion until adequate blood pressure and tissue perfusion persist without drug therapy.
• Gradually titrate dosage downward.
• To avoid extravasation, administer only into large vein (antecubital) or through central line. Don't use femoral vein in patients who are elderly or have occlusive vascular disorders.
To prevent delivery of large drug concentrations, avoid line stasis and flushing.
CNS: headache, anxiety
CV: bradycardia, severe hypertension, arrhythmias
Respiratory: respiratory difficulty
Skin: irritation with extravasation, necrosis
Other: ischemic injury
Drug-drug. Alpha-adrenergic blockers: antagonism of norepinephrine effects Antihistamines, ergot alkaloids, guanethidine, MAO inhibitors, oxytocin, tricyclic antidepressants: severe hypertension Bretylium, inhalation anesthetics: increased risk of arrhythmias
Check blood pressure every 2 minutes until desired pressure is achieved. Recheck every 5 minutes for duration of infusion.
• Maintain continuous ECG monitoring and blood pressure monitoring.
Be aware that headache may signal extreme hypertension and overdose.
• Monitor infusion site for extravasation.
Watch for signs and symptoms of peripheral vascular insufficiency (decreased capillary refill, pale to cyanotic to black skin color).
Never leave patient unattended during infusion.
• When patient is alert, explain why he's receiving drug.
• Reassure patient he'll be monitored continuously until he's stable.