Phenylephrine hydrochloride
Phenylephrine hydrochloride (Neo-Synephrine)
Phenylephrine hydrochloride
(fen-ill- EF-rin)
Pregnancy Category: C Nasal: Alconefrin 12, 25, and 50 Children's Nostril Doktors Duration Neo-Synephrine Solution Nostril Rhinall Vicks Sinex. Ophthalmic: AK-Dilate Dionephrine Mydfrin 2.5% Neo-Synephrine Neo-Synephrine Viscous Phenoptic Prefrin Liquifilm Relief. Parenteral: Neo-Synephrine. (Rx: Parenteral and Ophthalmic Solutions 2.5% or greater; OTC: Nasal products and ophthalmic solutions 0.12% or less)

Classification: Alpha-adrenergic agent (sympathomimetic)

See Also: See also Sympathomimetic Drugs .

Action/Kinetics: Stimulates alpha-adrenergic receptors, producing pronounced vasoconstriction and hence an increase in both SBP and DBP; reflex bradycardia results from increased vagal activity. Also acts on alpha receptors producing vasoconstriction in the skin, mucous membranes, and the mucosa as well as mydriasis by contracting the dilator muscle of the pupil. Resembles epinephrine, but it has more prolonged action and few cardiac effects. IV: Onset, immediate; duration, 15-20 min. IM, SC: Onset, 10-15 min; duration: 0.5-2 hr for IM and 50-60 min for SC. Nasal decongestion (topical): Onset: 15-20 min; duration, 30 min-4 hr. Ophthalmic: Time to peak effect for mydriasis, 15-60 min for 2.5% solution and 10-90 min for 10% solution. Duration: 0.5-1.5 hr for 0.12%, 3 hr for 2.5%, and 5-7 hr with 10% (when used for mydriasis). Excreted in urine.

Uses: Systemic: Vascular failure in shock, shock-like states, drug-induced hypotension or hypersensitivity. To maintain BP during spinal and inhalation anesthesia; to prolong spinal anesthesia. As a vasoconstrictor in regional analgesia. Paroxysmal SVT. Nasal: Nasal congestion due to allergies, sinusitis, common cold, or hay fever. Ophthalmologic: 0.12%: Temporary relief of redness of the eye associated with colds, hay fever, wind, dust, sun, smog, smoke, contact lens. 2.5% and 10%: Decongestant and vasoconstrictor, treatment of uveitis with posterior synechiae, open-angle glaucoma, refraction without cycloplegia, ophthalmoscopic examination, funduscopy, prior to surgery.

Contraindications: Severe hypertension, VT.

Special Concerns: Use with extreme caution in geriatric clients, severe arteriosclerosis, bradycardia, partial heart block, myocardial disease, hyperthyroidism and during pregnancy and lactation. Systemic absorption with nasal or ophthalmic use. Use of the 2.5% or 10% ophthalmic solutions in children may cause hypertension and irregular heart beat. In geriatric clients, chronic use of the 2.5% or 10% ophthalmic solutions may cause rebound miosis and a decreased mydriatic effect.

Side Effects: CV: Reflex bradycardia, arrhythmias (rare). CNS: Headache, excitability, restlessness. Ophthalmologic: Rebound miosis and decreased mydriatic response in geriatric clients, blurred vision.

Overdose Management: Symptoms: Ventricular extrasystoles, short paroxysms of ventricular tachycardia, sensation of fullness in the head, tingling of extremities. Treatment: Administer an alpha-adrenergic blocking agent (e.g., phentolamine).

Additional Drug Interactions: Anesthetics, halogenated hydrocarbon / May sensitize myocardium serious arrhythmias Bretylium / Effect of phenylephrine possible arrhythmias

How Supplied: Injection: 10 mg/mL; Liquid: 5 mg/5 mL; Nasal Solution: 0.125%, 0.25%, 0.5%, 1%; Ophthalmic Solution: 0.12%, 2.5%, 10%; Nasal Spray: 0.25%, 0.5%, 1%

Dosage
?IM, IV, SC Vasopressor, mild to moderate hypotension.
Adults: 2-5 mg (range: 1-10 mg), not to exceed an initial dose of 5 mg IM or SC repeated no more often than q 10-15 min; or, 0.2 mg (range: 0.1-0.5 mg), not to exceed an initial dose of 0.5 mg IV repeated no more often than q 10-15 min. Pediatric: 0.1 mg/kg (3 mg/m ²) IM or SC repeated in 1-2 hr if needed.
Vasopressor, severe hypotension and shock.
Adults: 10 mg by continuous IV infusion using 250-500 mL D5W or 0.9% NaCl injection given at a rate of 0.1-0.18 mg/min initial; then, give at a rate of 0.04-0.06 mg/min.
Prophylaxis of hypotension during spinal anesthesia.
Adults: 2-3 mg IM or SC 3-4 min before anesthetic given; subsequent doses should not exceed the previous dose by more than 0.1-0.2 mg. No more than 0.5 mg should be given in a single dose. Pediatric: 0.044-0.088 mg/kg IM or SC.
Hypotensive emergencies during spinal anesthesia.
Adults, initial: 0.2 mg IV; dose can be increased by no more than 0.2 mg for each subsequent dose not to exceed 0.5 mg/dose.
Prolongation of spinal anesthesia.
2-5 mg added to the anesthetic solution increases the duration of action up to 50% without increasing side effects or complications.
Vasoconstrictor for regional anesthesia.
Add 1 mg to every 20 mL of local anesthetic solution. If more than 2 mg phenylephrine is used, pressor reactions can be expected.
Paroxysmal SVT.
Initial: 0.5 mg (maximum) given by rapid IV injection (over 20-30 seconds). Subsequent doses are determined by BP and should not exceed the previous dose by more than 0.1-0.2 mg and should never be more than 1 mg.
?Nasal Solution, Nasal Spray
Adults and children over 12 years of age: 2-3 gtt of the 0.25% or 0.5% solution into each nostril q 3-4 hr as needed. In resistant cases, the 1% solution can be used but no more often than q 4 hr. Children, 6-12 years of age: 2-3 gtt of the 0.25% solution q 3-4 hr as needed. Infants, greater than 6 months of age: 1-2 gtt of the 0.16% solution into each nostril q 3-4 hr.
?Ophthalmic Solution, 0.12%, 2.5%, 10% Vasoconstriction, pupillary dilation.
1 gtt of the 2.5% or 10% solution on the upper limbus a few minutes following 1 gtt of topical anesthetic (prevents stinging and dilution of solution by lacrimation). An additional drop may be needed after 1 hr.
Uveitis.
1 gtt of the 2.5% or 10% solution with atropine. To free recently formed posterior synechiae, 1 gtt of the 2.5% or 10% solution to the upper surface of the cornea. Continue treatment the following day, if needed. In the interim, apply hot compresses for 5-10 min t.i.d. using 1 gtt of 1% or 2% atropine sulfate before and after each series of compresses.
Glaucoma.
1 gtt of 10% solution on the upper surface of the cornea as needed. Both the 2.5% and 10% solutions may be used with miotics in clients with open-angle glaucoma.
Surgery.
2.5% or 10% solution 30-60 min before surgery for wide dilation of the pupil.
Refraction.
Adults: 1 gtt of a cycloplegic (homatropine HBr, atropine sulfate, cyclopentolate, tropicamide HCl, or a combination of homatropine and cocaine HCl) in each eye followed in 5 min with 1 gtt of 2.5% phenylephrine solution and in 10 min with another drop of cycloplegic. The eyes are ready for refraction in 50-60 min. Children: 1 gtt of atropine sulfate, 1%, in each eye followed in 10-15 min with 1 gtt of phenylephrine solution, 2.5%, and in 5-10 min with a second drop of atropine sulfate, 1%. The eyes are ready for refraction in 1-2 hr.
Ophthalmoscopic examination.
1 gtt of 2.5% solution in each eye. The eyes are ready for examination in 15- 30 min and the effect lasts for 1-3 hr.
Minor eye irritations.
1-2 gtt of the 0.12% solution in the eye(s) up to q.i.d. as needed.