Neo-Synephrine
phenylephrine
(fen-il-eff-rin) phenylephrine,Neo-Synephrine
(trade name)Classification
Therapeutic: vasopressorsPharmacologic: adrenergics
Pregnancy Category: C (Ophth, Parenteral)
For ophthalmic use see
Indications
- Prolongation of the duration of spinal anesthesia,
- Localization of the effect of regional anesthesia.
Action
Therapeutic effects
Pharmacokinetics
Time/action profile (vasopressor effects)
| ROUTE | ONSET | PEAK | DURATION |
|---|---|---|---|
| IV | immediate | unknown | 15–20 min |
| IM | 10–15 min | unknown | 0.5–2 hr |
| Subcut | 10–15 min | unknown | 50–60 min |
Contraindications/Precautions
Adverse Reactions/Side Effects
Central nervous system
- anxiety
- dizziness
- headache
- insomnia
- nervousness
- restlessness
- trembling
- weakness
Respiratory
- dyspnea
- respiratory distress
Cardiovascular
- arrhythmias (life-threatening)
- bradycardia
- chest pain
- hypertension
- tachycardia
- vasoconstriction
Dermatologic
- blanching
- pallor
- piloerection
- sweating
Local
- phlebitis
- sloughing at IV sites
Neurologic
- tremor
Interactions
Drug-Drug interaction
Use with general anesthetics may result in myocardial irritability; use with extreme caution.Use with MAO inhibitors, ergot alkaloids (ergonovine, methylergonovine ), or oxytocics results in severe hypertension.Alpha-adrenergic blockers (phentolamine ) may antagonize vasopressor effects.Atropine blocks bradycardia from phenylephrine and enhances pressor effects.Route/Dosage
Hypotension
Hypotension during Spinal Anesthesia
Vasoconstrictor for Regional Anesthesia
Prolongation of Spinal Anesthesia
Availability (generic available)
Nursing implications
Nursing assessment
- Monitor BP every 2–3 min until stabilized and every 5 min thereafter during IV administration.
- Monitor ECG continuously for arrhythmias during IV administration.
- Assess IV site frequently throughout infusion. Antecubital or other large vein should be used to minimize risk of extravasation, which may cause tissue necrosis. If extravasation occurs, the site should be infiltrated promptly with 10–15 mL of 0.9% NaCl solution containing 5–10 mg of phentolamine to prevent necrosis and sloughing.
Potential Nursing Diagnoses
Decreased cardiac output (Indications)Ineffective tissue perfusion (Indications)
Implementation
- high alert: Patient harm and fatalities have occurred from medication errors with phenylephrine. Prior to administration, have second practitioner independently check original order, dose calculations, concentration, route of administration and infusion pump settings.
Intravenous Administration
- Intravenous: Blood volume depletion should be corrected, if possible, before initiation of IV phenylephrine.
- Diluent: Dilute each 1 mg with 9 mL of sterile water for injection.
- Rate: Administer each single dose over 1 min.
- Continuous Infusion: Diluent: Dilute 10 mg in 250 or 500 mL of dextrose/Ringer’s or lactated Ringer’s combination, dextrose/saline combinations, D5W, D10W, Ringer’s or LR, 0.45% NaCl, or 0.9% NaCl.Concentration: 125,000 or 150,000 solution, respectively.
- Rate: Titrate rate according to patient response. Infuse via infusion pump to ensure accurate dose rate.
- Y-Site Compatibility: alfentanil, amikacin, aminophylline, amiodarone, amphotericin B liposome, anidulafungin, argatroban, ascorbic acid, atropine, aztreonam, benztropine, bivalirudin, bleomycin, bumetanide, buprenorphine, butorphanol, calcium chloride, calcium gluconate, carboplatin, carmustine, caspofungin, cefazolin, cefonocid, cefoperazone, cefotaxime, cefotetan, cefoxitin, ceftazidime, cephalothin, chloramphenicol, cisatracurium, cisplatin, clindamycin, cyanocobalamin, cyclophosphamide, cyclosporine, cytarabine, dactinomycin, daptomycin, dexamethasone, dexmedetomidine, digoxin, diltiazem, diphenhydramine, dobutamine, docetaxel, dopamine, doripenem, doxorubicin hydrochloride, doxycycline, enalaprilat, ephedrine, epinephrine, epirubicin, epoetin alfa, eptifibatide, ertapenem, erythromycin, esmolol, etomidate, etoposide, etoposide phosphate, famotidine, fenoldopam, fentanyl, fluconazole, fludarabine, fluorouracil, folic acid, gentamicin, glycopyrrolate, granisetron, heparin, hetastarch, hydrocortisone, hydromorphone, idarubicin, ifosfamide, imipenem/cilastatin, irinotecan, isoproterenol, ketorolac, labetalol, levofloxacin, lidocaine, linezolid, lorazepam, magnesium sulfate, mannitol, mechlorethamine, meperidine, methotraxate, methoxamine, methyldopate, methtylprednisolone, metoclopramide, metoprolol, metronidazole, micafungin, miconazole, midazolam, milrinone, mitoxantrone, morphine, multivitamins, mycophenolate, nafcillin, nalbuphine, naloxone, nitroglycerin, nitroprusside, norepinephrine, octreotide, ondansetron, oxacillin, oxaliplatin, oxytocin, paclitaxel, palonsetron, pantoprazole, papaverine, penicillin G, pentobarbi1tol, phenobarbitol, phentolamine, phytonadione, piperacillin/tazobactam, potassium acetate, potassium chloride, procainamide, prochlorperazine, promethazine, propranolol, protamine, pyridoxime, quinupristin/dalfopristin, ranitidine, remifentanil, rocuronium, sodium acetate, sodium bicarbonate, streptokinase, succinylcholine, sufentanil, tacrolimus, telavancin, teniposide, theophylline, thiamine, thiotepa, ticarcillin/clavulanate, tigecycline, tirofiban, tobramycin, tolazoline, vancomycin, vasopressin, vecuronium, verapamil, vincristine, vinorelbine, voriconazole, zidovudine, zoledronic acid
- Y-Site Incompatibility: acyclovir, amphotericin B colloidal, azathioprine, dantrolene, diazepam, diazoxide, furosemide, ganciclovir, indomethacin, insulin, pentamidine, phenytoin, trimethoprim/sulfamethoxazole, thiopental
- Anesthesia: Phenylephrine 2–5 mg may be added to spinal anesthetic solution to prolong anesthesia.
- Phenylephrine 1 mg may be added to each 20 mL of local anesthetic to produce vasoconstriction.
Patient/Family Teaching
- Intravenous: Instruct patient to report headache, dizziness, dyspnea, or pain at IV infusion site promptly.
Evaluation/Desired Outcomes
- Increase in BP to normal range.
- Prolonged duration of spinal anesthesia.
- Localization of regional anesthesia.