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Related to Regitine: Phentolamine mesylate
Pregnancy Category: C
Pharmacologic: alpha adrenergic blockers
ClassificationTherapeutic: agents pheochromocytoma
Pharmacologic: alpha adrenergic blockers
Intravenous: Control of BP during surgical removal of a pheochromocytoma.IV, Infiltration: Prevention and treatment of dermal necrosis and sloughing following extravasation of norepinephrine, phenylephrine, or dopamine.Local: Reversal of soft-tissue anesthesia (of lip and tongue) resulting from an intraoral submucosal injection of a local anesthetic containing a vasconstrictor. Intramuscular: Intravenous: Treatment of hypertension associated with pheochromocytoma or adrenergic (sympathetic) excess, such as administration of phenylephrine, tyramine-containing foods in patients on MAO inhibitor therapy, or clonidine withdrawal.
Produces incomplete and short-lived blockade of alpha-adrenergic receptors located primarily in smooth muscle and exocrine glands.
Induces hypotension by direct relaxation of vascular smooth muscle and by alpha blockade.
Increases blood flow to submucosal tissue through blockade of alpha receptors.
Reduction of BP in situations in which hypertension is due to adrenergic (sympathetic) excess.
When infiltrated locally, reverses vasoconstriction caused by norepinephrine or dopamine.
Reverses local anesthetic effects (restores normal lip and tongue sensation).
Absorption: Well absorbed following IM administration; completely available after local injection.
Metabolism and Excretion: 10% excreted unchanged by kidneys.
Half-life: 19 min (IV); 2–3 hr (local injection).
Time/action profile (alpha-adrenergic blockade)
|IM||unknown||20 min||30–45 min|
|IV||immediate||2 min||15–30 min|
Contraindicated in: Hypersensitivity;Coronary or cerebral arteriosclerosis;Renal impairment.
Use Cautiously in: Peptic ulcer disease; Obstetric / Lactation: Safety not established; Pediatric: Children <6 yr or <15 kg (Oraverse) (safety not established); Geriatric: More susceptible to hypotensive effects; ↓ dose recommended.
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
Intravenous (Adults) 5 mg given 1–2 hr preop, repeated as necessary. May be infused at a rate of 0.5–1 mg/min during surgery.
Intravenous Intramuscular (Children) 1 mg or 0.1 mg/kg (3 mg/m2) given 1–2 hr preop, repeated IV as necessary during surgery.Prevention of Dermal Necrosis during Infusion of Norepinephrine, Phenylephrine, or Dopamine
Intravenous (Adults) Add 10 mg phentolamine to every 1000 mL of fluid containing norepinephrine.Treatment of Dermal Necrosis Following Extravasation of Norepinephrine, Phenylephrine, or Dopamine
Infiltrate: (Adults) 5–10 mg.
Infiltrate: (Children) 0.1–0.2 mg/kg (up to 10 mg).Reversal of Intraoral Submucosal Anesthesia Following Dental Procedures (Oraverse)
Infiltrate or Block Injection: (Adults and Children ≥6 yr and >30 k g) Dose administered is based on number of cartridges of local anesthetic with vasoconstrictor administered: 1/2 cartridge local anesthetic—0.2 mg phentolamine (1/2 cartridge); 1 cartridge local anesthetic—0.4 mg phentolamine (1 cartridge); 2 cartridges local anesthetic—0.8 mg phentolamine (2 cartridges).
Infiltrate or Block Injection: (Children ≥6 yr and 15–30 kg) Do not exceed dose of 0.2 mg (1/2 cartridge).
Availability (generic available)
Powder for injection: 5 mg/vial
Injection for local infiltration/block injection: 0.4 mg/cartridge
- 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.
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