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Therapeutic class: Diagnostic agent, antihypertensive agent in pheochromocytoma
Pregnancy risk category C
Competitively blocks postsynaptic (alpha1) and presynaptic (alpha2) adrenergic receptors. Acts on arterial tree and venous bed, reducing total peripheral resistance and lowering venous return to heart.
Powder for injection: 5 mg
Indications and dosages
➣ To prevent or control hypertensive episodes before or during pheochromocytomectomy
Adults: 5 mg I.V. or I.M. 1 to 2 hours before surgery, then 5 mg I.V. during surgery as indicated
Children: 1 mg I.V. or I.M. 1 to 2 hours before surgery, then 1 mg I.V. during surgery as indicated
➣ To aid pheochromocytoma diagnosis
Adults: 2.5 or 5 mg (in 1 ml of sterile water) by I.V. injection; record blood pressure q 30 seconds for 3 minutes, then q minute for next 7 minutes. Or 5 mg (in 1 ml sterile water) I.M.; record blood pressure q 5 minutes for 30 to 45 minutes.
➣ To prevent or treat dermal necrosis after norepinephrine extravasation
Adults: For prevention, add 10 mg to each liter of I.V. solution containing norepinephrine. For treatment, inject 5 to 10 mg in 10 ml of normal saline solution into extravasated area within 12 hours.
• Hypertensive crisis caused by MAO inhibitors
• Rebound hypertension caused by withdrawal of clonidine, propranolol, or other antihypertensives
• Erectile dysfunction (given with papaverine)
• Hypersensitivity to drug
• Coronary artery disease
• Myocardial infarction (MI) or history of MI
• Coronary insufficiency
Use cautiously in:
• patients receiving cardiac glycosides concurrently
• pregnant or breastfeeding patients.
• Reconstitute powder by diluting with 1 ml of sterile water for injection.
• For pheochromocytoma diagnosis, withhold sedatives, analgesics, and nonessential drugs for 24 to 72 hours before test (until hypertension returns). Keep patient supine until blood pressure stabilizes; then rapidly inject drug I.V. Maximum effect usually occurs within 2 minutes of dosing.
CNS: weakness, dizziness
CV: tachycardia, acute and prolonged hypotension, orthostatic hypotension, arrhythmias
EENT: nasal congestion
GI: nausea, vomiting, diarrhea
Drug-drug. Ephedrine, epinephrine: antagonism of these drugs' effects
Drug-herbs. Ephedra (ma huang): antagonism of vasoconstrictive effects
• When using for norepinephrine extravasation, monitor injection site closely and assess blood pressure, heart rate, and respiratory rate.
• For pheochromocytoma diagnosis, monitor blood pressure. In pheochromocytoma, systolic and diastolic pressures drop immediately and steeply. Monitor and record blood pressure immediately after injection, at 30-second intervals for first 3 minutes, and at 1-minute intervals for next 7 minutes. Systolic decrease of 60 mmHg and diastolic decrease of 25 mmHg within 2 minutes after I.V. administration indicates a positive reaction for pheochromocytoma.
• Explain drug administration procedure.
☞ Instruct patient to promptly report adverse reactions. Assure him he'll be monitored closely.
• Tell patient to withhold other drugs (especially sedatives and analgesics) for at least 24 hours before pheochromocytoma testing, if appropriate.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and herbs mentioned above.
ClassificationTherapeutic: agents pheochromocytoma
Pharmacologic: alpha adrenergic blockers
Time/action profile (alpha-adrenergic blockade)
|IM||unknown||20 min||30–45 min|
|IV||immediate||2 min||15–30 min|
Adverse Reactions/Side EffectsWith parenteral use
Central nervous system
- cerebrovascular spasm (life-threatening)
Ear, Eye, Nose, Throat
- nasal stuffiness
- mi (life-threatening)
- angina (most frequent)
- arrhythmias (most frequent)
- tachycardia (most frequent)
- abdominal pain (most frequent)
- diarrhea (most frequent)
- nausea (most frequent)
- vomiting (most frequent)
- aggravation of peptic ulcer
- injection site pain (local)
Drug-Drug interactionAntagonizes the effects of alpha-adrenergic stimulants.May ↓ pressor response to ephedrine or phenylephrine.Severe hypotension may occur with concurrent use of epinephrine or methoxamine.↓ peripheral vasoconstriction from high doses of dopamine.
Route/DosageHypertension Associated with Pheochromocytoma—Before/During Surgery
Availability (generic available)
- Monitor BP, pulse, and ECG every 2 min until stable during IV administration. If hypotensive crisis occurs, epinephrine is contraindicated and may cause paradoxic further decrease in BP; norepinephrine may be used.
Potential Nursing DiagnosesIneffective tissue perfusion (Indications)
Risk for injury (Indications)
- Patient should remain supine throughout parenteral administration.
- pH: 4.5–6.5.
- Intravenous: Diluent: Reconstitute each 5 mg with 1 mL of sterile water for injection or 0.9% NaCl. Discard unused solution.Concentration: 5 mg/mL.
- Rate: Inject each 5 mg over 1 min.
- Continuous Infusion: Dilute 5–10 mg in 500 mL of D5W.
- Rate: Titrate infusion rate according to patient response.
- May also add 10 mg to every 1000 mL of fluid containing norepinephrine for prevention of dermal necrosis and sloughing. Does not affect pressor effect of norepinephrine.
- Syringe Compatibility: papaverine
- Y-Site Compatibility: alfentanil, amikacin, aminophylline, amiodarone, ascorbic acid, atropine, aztreonam, benztropine, bumetanide, buprenorphine, butorphanol, calcium chloride, calcium gluconate, ceftazidime, ceftriaxone, chlorpromazine, cimetidine, cyanocobalamin, cyclosporine, dactinomycin, daptomycin, digoxin, diltiazem, diphenhydramine, dobutamine, docetaxel, dobutamine, docetaxel, dopamine, doxycycline, enalaprilat, epinephrine, epoetin, ertapenem, erythromycin, esmolol, etoposide phosphate, famotidine, fenoldopam, fentanyl, fluconazole, fludarabine, folic acid, gemcitabine, gentamicin, glycopyrrolate, granisetron, heparin, hydrocortisone sodium succinate, imipenem-cilastatin, isoproterenol, labetalol, lidocaine, linezolid, lorazepam, magnesium sulfate, mannitol, mechlorethamine, meperidine, metaraminol, methoxamine, methyldopa, metoclopramide, metoprolol, metronidazole, midazolam, minocycline, mitoxantrone, morphine, multivitamin injection, nafcillin, naloxone, nesiritide, nitroglycerin, nitroprusside, norepinephrine, octreotide, ondansetron, oxaliplatin, oxytocin, paclitaxel, palonosetron, pantoprazole, pemetrexed, pentamidine, pentazocine, phenylephrine, phytonadione, piperacillin/tazobactam, potassium chloride, procainamide, prochlorperazine, promethazine, propranolol, protamine, pyridoxime, quinidine, ranitidine, sodium bicarbonate, streptokinase, succinylcholine, sufentanil, tacrolimus, teniposide, theophylline, thiamine, thiotepa, ticarcillin/clavulanate, tirofiban, tobramycin, tolazoline, trimethophan, vancomycin, vasopressin, verapamil, vinorelbine, voriconazole
- Y-Site Incompatibility: amphotericin B colloidal, cefazolin, cefoperazone, cefotetan, cefoxitin, cefuroxime, chloramphenicol, clindamycin, dantrolene, dexamethasone, diazepam, diazoxide, furosemide, ganciclovir, insulin, ketorolac, moxalactam, penicillin G, pentobarbital, phenobarbital, phenytoin, trimethoprim/sulfamethoxazole
- Additive Compatibility: dobutamine, norepinephrine
- Infiltration: Dilute 5–10 mg of phentolamine in 10 mL of 0.9% NaCl. For children, use 0.1–0.2 mg/kg up to a maximum of 10 mg. Infiltrate site of extravasation promptly. Must be given within 12 hr of extravasation to be effective.
- Advise patient to change positions slowly to minimize orthostatic hypotension.
- Instruct patient to notify health care professional if chest pain occurs during IV infusion.
- Decrease in BP.
- Prevention of dermal necrosis and sloughing in extravasation of norepinephrine, dopamine, and phenylephrine.
- Restoration of normal lip and tongue sensation following local anesthesia.