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Phenylephrine  (neo-synephrine®)

Actions: Stimulates alpha-adrenergic receptors, increasing blood pressure and causing pronounced vasoconstriction in skin, mucous membranes, and mucosa. Produces mydriasis by contracting pupillary dilator muscle.

Nasal congestion: (ORAL)
Dosing (adult): 10mg (1 tablet) every 4 hours as needed. Maximum: 60mg per day. Sample product: Sudafed PE™

Nasal decongestant (therapy should not exceed 3 continuous days):
6-12 years: Instill 1-2 sprays or instill 1-2 drops every 4 hours of 0.25% solution as needed

Children >12 years and Adults: Instill 1-2 sprays or instill 1-2 drops every 4 hours of 0.25% to 0.5% solution as needed; 1% solution may be used in adult in cases of extreme nasal congestion; do not use nasal solutions more than 3 days

Pseudoephedrine (sudafed)

Actions:  Pseudoephedrine is a sympathomimetic amine. Its principal mechanism of action relies on its indirect action on the adrenergic receptor system. The vasoconstriction that pseudoephedrine produces is believed to be principally an α-adrenergic receptor response.  While it may have weak or no direct agonist activity at α- and β-adrenergic receptors, the principal mechanism is to cause the release of endogenous norepinephrine (noradrenaline) from storage vesicles in presynaptic neurons.


Oral:  Children:
6-12 years: 30 mg every 6 hours; maximum: 120 mg/24 hours

Adults: 30 to 60 mg every 4-6 hours. Sustained release: 120 mg every 12 hours. Maximum: 240 mg/24 hours

Gelcap (Dimetapp® Decongestant): 30 mg
Liquid, as hydrochloride:
Triaminic® Allergy Congestion: 15 mg/5 mL (120 mL) [contains benzoic acid]
Syrup, as hydrochloride: 30 mg/5 mL (120 mL, 480 mL)
Tablet, as hydrochloride: 30 mg, 60 mg
Tablet, extended release, as hydrochloride:
Dimetapp® 12-Hour Non-Drowsy Extentabs®, Sudafed® 12 Hour: 120 mg
Sudafed® 24 Hour: 240 mg


National Institutes of Health, U.S. National Library of Medicine, DailyMed Database.
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