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Phenylephrine (Systemic)

Pronunciation

Pronunciation

(fen il EF rin)

Index Terms

  • Phenylephrine HCl
  • Phenylephrine Hydrochloride

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Liquid, Oral, as hydrochloride:

Little Colds Decongestant: 2.5 mg/mL (30 mL) [alcohol free, dye free, saccharin free; contains sodium benzoate; grape flavor]

Solution, Injection, as hydrochloride:

Neo-Synephrine: 10 mg/mL (1 mL [DSC]) [contains sodium metabisulfite]

Generic: 10 mg/mL (1 mL, 5 mL, 10 mL)

Solution, Intravenous, as hydrochloride:

Vazculep: 10 mg/mL (1 mL, 5 mL, 10 mL) [contains sodium metabisulfite]

Solution, Oral, as hydrochloride:

PediaCare Childrens Decongest: 2.5 mg/5 mL (118 mL [DSC]) [contains edetate disodium, fd&c red #40, sodium benzoate]

Sudafed PE Childrens: 2.5 mg/5 mL (118 mL) [alcohol free, sugar free; contains edetate disodium, fd&c red #40, sodium benzoate; berry flavor]

Tablet, Oral, as hydrochloride:

Medi-Phenyl: 5 mg

Nasal Decongestant: 10 mg [contains fd&c blue #2 (indigotine), fd&c red #40, fd&c yellow #6 aluminum lake]

Nasal Decongestant PE Max St: 10 mg [pseudoephedrine free; contains fd&c red #40 aluminum lake]

Non-Pseudo Sinus Decongestant: 10 mg [contains fd&c red #40 aluminum lake, fd&c yellow #6 aluminum lake]

Sudafed PE Maximum Strength: 10 mg [contains fd&c red #40 aluminum lake, fd&c yellow #10 aluminum lake, fd&c yellow #6 aluminum lake]

Sudafed PE Maximum Strength: 10 mg [contains fd&c red #40 aluminum lake, fd&c yellow #6 aluminum lake]

Sudafed PE Maximum Strength: 10 mg [pseudoephedrine free; contains fd&c red #40 aluminum lake, fd&c yellow #10 aluminum lake, fd&c yellow #6 aluminum lake]

Sudogest PE: 10 mg [contains fd&c red #40]

Brand Names: U.S.

  • Little Colds Decongestant [OTC]
  • Medi-Phenyl [OTC]
  • Nasal Decongestant PE Max St [OTC]
  • Nasal Decongestant [OTC]
  • Neo-Synephrine [DSC]
  • Non-Pseudo Sinus Decongestant [OTC]
  • PediaCare Childrens Decongest [OTC] [DSC]
  • Sudafed PE Childrens [OTC]
  • Sudafed PE Maximum Strength [OTC]
  • Sudogest PE [OTC]
  • Vazculep

Pharmacologic Category

  • Alpha-Adrenergic Agonist

Pharmacology

Potent, direct-acting alpha-adrenergic agonist with virtually no beta-adrenergic activity; produces systemic arterial vasoconstriction. Such increases in systemic vascular resistance result in dose dependent increases in systolic and diastolic blood pressure and reductions in heart rate and cardiac output especially in patients with heart failure.

Absorption

Oral: Rapid and complete (Kanfer 1993)

Distribution

Vd: Initial: 26 to 61 L; Vdss: 184 to 543 L (mean: 340 L) (Hengstmann 1982)

Metabolism

Hepatic via oxidative deamination (Oral: 24%; IV: 50%); Undergoes sulfation (Oral [mostly within gut wall]: 46%; IV: 8%) and some glucuronidation; forms inactive metabolites (Kanfer 1993)

Excretion

Urine (mostly as inactive metabolites)

Onset of Action

Blood pressure increase/vasoconstriction: IM, SubQ: 10 to 15 minutes; IV: Immediate

Nasal decongestant: Oral: 15 to 30 minutes (Kollar 2007)

Time to Peak

Oral: 0.75 to 2 hours (Kanfer 1993)

Duration of Action

Blood pressure increase/vasoconstriction: IM: 1 to 2 hours; IV: ~15 to 20 minutes; SubQ: 50 minutes

Nasal decongestant: Oral: ≤4 hours (Kollar 2007)

Half-Life Elimination

Alpha phase: ~ 5 minutes; Terminal phase: 2 to 3 hours (Hengstmann 1982; Kanfer 1993)

Use: Labeled Indications

Treatment of hypotension, vascular failure in shock (see "Note"); as a vasoconstrictor in regional analgesia; as a decongestant [OTC]

Note: Not recommended for routine use in the treatment of septic shock (SCCM [Dellinger, 2013]).

Contraindications

Hypersensitivity to phenylephrine or any component of the formulation

Injection: Severe hypertension; ventricular tachycardia

Vazculep: There are no contraindications listed in the manufacturer's labeling.

OTC labeling (Oral): When used for self-medication: Use with or within 14 days of MAO inhibitor therapy

Dosing: Adult

Hypotension/shock: Note: The Society of Critical Care Medicine (SCCM) does not recommend phenylephrine for septic shock except in the following circumstances: Norepinephrine (preferred first-line agent) is associated with serious arrhythmias, cardiac output is known to be high and blood pressure persistently low, or when the combination of inotrope/vasopressor and low-dose vasopressin failed to achieve target mean arterial pressure and phenylephrine is used as salvage therapy (SCCM [Dellinger 2013]).

IV bolus: 100 to 500 mcg/dose every 10 to 15 minutes as needed (initial dose should not exceed 500 mcg)

IV infusion: Initial dose: 100 to 180 mcg/minute, or alternatively, 0.5 mcg/kg/minute; titrate to desired response. Dosing ranges between 0.4 to 9.1 mcg/kg/minute have been reported when treating septic shock (Gregory 1991).

ACLS guideline recommendations (to treat severe hypotension [eg, systolic blood pressure <70 mm Hg] and low total peripheral resistance): Initial dose: 0.5 to 2 mcg/kg/minute; titrate to effect (AHA [Peberdy 2010]).

Hypotension during anesthesia:

IV bolus: 40 to 100 mcg/dose every 1 to 2 minutes as needed (total dose should not exceed 200 mcg)

IV infusion: Initial dose: 10 to 35 mcg/minute adjusted according to blood pressure goal (not to exceed 200 mcg/minute)

Nasal congestion: Oral: OTC labeling: 10 mg every 4 hours as needed for ≤7 days (maximum: 60 mg/24 hours)

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Hypotension/shock: Note: The Society of Critical Care Medicine (SCCM) does not recommend phenylephrine for septic shock except in the following circumstances: Norepinephrine (preferred first-line agent) is associated with serious arrhythmias, cardiac output is known to be high and blood pressure persistently low, or when the combination of inotrope/vasopressor and low-dose vasopressin failed to achieve target mean arterial pressure and phenylephrine is used as salvage therapy (SCCM [Dellinger 2013]).

IV bolus: 5 to 20 mcg/kg/dose every 10 to 15 minutes as needed

IV infusion: 0.1 to 0.5 mcg/kg/minute

Nasal congestion: Oral: OTC labeling:

4 to <6 years: 2.5 mg every 4 hours as needed for ≤7 days (maximum: 15 mg/24 hours)

6 to <12 years: 5 mg every 4 hours as needed for ≤7 days (maximum: 30 mg/24 hours)

≥12 years: Refer to adult dosing.

Reconstitution

Solution for injection:

IV infusion: May dilute 10 mg in 500 mL NS or D5W (Vazculep preferred dilution). May also dilute 50 mg in 500 mL NS, 100 mg in 500 mL NS, or 1250 mg in 500 mL NS (Gupta 2004; Weber 1970).

IV injection: May dilute with NS to a concentration of 0.1 mg/mL (Kiser 2007). May also dilute with SWFI, NS, or D5W to a higher concentration of 1 mg/mL. Note: For bolus administration, Vazculep prescribing information recommends dilution to the lower concentration of 0.1 mg/mL solution in NS or D5W.

Administration

IV:

Hypotension/shock: May be administered as an intermittent IV bolus over 20 to 30 seconds or via continuous infusion (after diluting). When administering as a continuous infusion, central line administration is preferred. IV infusions require an infusion pump.

Hypotension during anesthesia: Administer as an IV bolus over 20 to 30 seconds.

Vesicant; ensure proper needle or catheter placement prior to and during infusion; avoid extravasation.

Extravasation management: If extravasation occurs, stop infusion immediately and disconnect (leave cannula/needle in place); gently aspirate extravasated solution (do NOT flush the line); remove needle/cannula; elevate extremity. Initiate phentolamine (or alternative antidote). Apply dry warm compresses (Hurst 2004).

Phentolamine: Dilute 5 to 10 mg in 10 to 15 mL NS and administer into extravasation site as soon as possible after extravasation (AHA [Peberdy 2010]).

Alternatives to phentolamine:

Nitroglycerin topical 2% ointment (based on limited case reports in neonates/infants): Apply 4 mm/kg as a thin ribbon to the affected areas; may repeat after 8 hours if needed (Wong 1992) or apply a 1-inch strip on the affected site (Denkler 1989).

Terbutaline (based on limited case reports): Infiltrate extravasation area using a solution of terbutaline 1 mg diluted to 10 mL in NS (large extravasation site; administration volume varied from 3 to 10 mL) or 1 mg diluted in 1 mL NS (small/distal extravasation site; administration volume varied from 0.5 to 1 mL) (Stier 1999).

Dietary Considerations

Some products may contain phenylalanine and/or sodium.

Compatibility

Stable in D5LR, D5R, D51/4NS, D51/2NS, D5NS, D5W, D10W, LR, R, 1/2NS, NS, sodium bicarbonate 5%.

Y-site administration: Incompatible with thiopental.

Storage

Solution for injection: Store vials at controlled room temperature of 15°C to 25°C (59°F to 77°F). Protect from light. Do not use solution if brown or contains a precipitate.

IV infusion: Concentrations of 0.1 and 0.2 mg/mL in NS are stable for at least 14 days at room temperature of 25°C (77°F) (Gupta 2004). Dilution of 2.5 mg/mL in NS retained potency for at least 24 hours at 22°C (Weber 1970). Vazculep: Do not hold diluted solutions for longer than 4 hours at room temperature or 24 hours refrigerated.

Stability in syringes: Concentration of 0.1 mg/mL in NS (polypropylene syringes) is stable for at least 30 days at -20°C (-4°F), 3°C to 5°C (37°F to 41°F), or 23°C to 25°C (73.4°F to 77°F) (Kiser 2007). Vazculep: Do not hold diluted solutions for longer than 4 hours at room temperature or 24 hours refrigerated.

Oral: Store at controlled room temperature of 15°C to 25°C (59°F to 77°F). Protect from light.

Drug Interactions

Acetaminophen: May increase the serum concentration of Phenylephrine (Systemic). Monitor therapy

Alpha1-Blockers: May diminish the vasoconstricting effect of Alpha1-Agonists. Similarly, Alpha1-Agonists may antagonize Alpha1-Blocker vasodilation. Monitor therapy

AtoMOXetine: May enhance the hypertensive effect of Sympathomimetics. AtoMOXetine may enhance the tachycardic effect of Sympathomimetics. Monitor therapy

Benzylpenicilloyl Polylysine: Alpha1-Agonists may diminish the diagnostic effect of Benzylpenicilloyl Polylysine. Management: Consider use of a histamine skin test as a positive control to assess a patient's ability to mount a wheal and flare response. Consider therapy modification

Cannabinoid-Containing Products: May enhance the tachycardic effect of Sympathomimetics. Exceptions: Cannabidiol. Monitor therapy

Doxofylline: Sympathomimetics may enhance the adverse/toxic effect of Doxofylline. Monitor therapy

Ergot Derivatives: May enhance the hypertensive effect of Alpha1-Agonists. Ergot Derivatives may enhance the vasoconstricting effect of Alpha1-Agonists. Exceptions: Ergoloid Mesylates; Nicergoline. Avoid combination

FentaNYL: Alpha1-Agonists may decrease the serum concentration of FentaNYL. Specifically, fentanyl nasal spray serum concentrations may decrease and onset of effect may be delayed. Monitor therapy

Hyaluronidase: May enhance the vasoconstricting effect of Phenylephrine (Systemic). Management: Avoid the use of hyaluronidase to enhance dispersion or absorption of phenylephrine. Use of hyaluronidase for other purposes in patients receiving phenylephrine may be considered as clinically indicated. Avoid combination

Iobenguane I 123: Sympathomimetics may diminish the therapeutic effect of Iobenguane I 123. Avoid combination

Ioflupane I 123: Phenylephrine (Systemic) may diminish the diagnostic effect of Ioflupane I 123. Monitor therapy

Linezolid: May enhance the hypertensive effect of Sympathomimetics. Management: Reduce initial doses of sympathomimetic agents, and closely monitor for enhanced pressor response, in patients receiving linezolid. Specific dose adjustment recommendations are not presently available. Consider therapy modification

MAO Inhibitors: May enhance the hypertensive effect of Alpha1-Agonists. While linezolid is expected to interact via this mechanism, management recommendations differ from other monoamine oxidase inhibitors. Refer to linezolid specific monographs for details. Exceptions: Linezolid; Tedizolid. Avoid combination

Propacetamol: May increase the serum concentration of Phenylephrine (Systemic). Management: Monitor patients closely for increased side effects of phenylephrine if propacetamol is used concomitantly. Patients with underlying blood pressure issues or arrhythmias may need closer monitoring and may warrant consideration of alternative therapies. Monitor therapy

Sympathomimetics: May enhance the adverse/toxic effect of other Sympathomimetics. Monitor therapy

Tedizolid: May enhance the hypertensive effect of Sympathomimetics. Tedizolid may enhance the tachycardic effect of Sympathomimetics. Monitor therapy

Tricyclic Antidepressants: May enhance the vasopressor effect of Alpha1-Agonists. Tricyclic Antidepressants may diminish the vasopressor effect of Alpha1-Agonists. Monitor therapy

Adverse Reactions

Frequency not defined.

Injection:

Cardiovascular: Cardiac arrhythmia (rare), exacerbation of angina, hypertension, hypertensive crisis, ischemia, localized blanching, low cardiac output, peripheral vasoconstriction (severe), reflex bradycardia, visceral vasoconstriction (severe), worsening of heart failure

Central nervous system: Anxiety, dizziness, excitability, headache, insomnia, nervousness, paresthesia, precordial pain (or discomfort), restlessness

Dermatologic: Pallor, piloerection, pruritus

Endocrine & metabolic: Metabolic acidosis

Gastrointestinal: Epigastric pain, gastric irritation, nausea, vomiting

Genitourinary: Decreased renal blood flow, decreased urine output

Hypersensitivity: Hypersensitivity reaction (including skin rash, urticaria, leukopenia, agranulocytosis, thrombocytopenia)

Local: Extravasation which may lead to necrosis and sloughing of surrounding tissue

Neuromuscular & skeletal: Neck pain, tremor, weakness

Ophthalmic: Blurred vision

Respiratory: Dyspnea, exacerbation of pulmonary arterial hypertension, respiratory distress

Oral: Central nervous system: Anxiety, dizziness, excitability, headache, insomnia, nervousness, restlessness

ALERT: U.S. Boxed Warning

Experienced physician (injection):

Physicians should completely familiarize themselves with the complete contents of this monograph before prescribing phenylephrine injection.

Warnings/Precautions

Concerns related to adverse effects:

• Cardiovascular effects: Intravenous use of phenylephrine may cause severe bradycardia (likely baroreflex mediated) and reduced cardiac output due to an increase in cardiac afterload especially in patients with preexisting cardiac dysfunction (Goertz 1993; Yamazaki 1982). May also precipitate angina in patients with severe coronary artery disease and increase pulmonary arterial pressure. Use with caution in patients with preexisting bradycardia, partial heart block, myocardial disease, or severe coronary artery disease. Avoid or use with extreme caution in patients with heart failure or cardiogenic shock; increased systemic vascular resistance may significantly reduce cardiac output. Avoid use in patients with hypertension (contraindicated in severe hypertension); monitor blood pressure closely and adjust infusion rate. May also cause excessive peripheral and visceral vasoconstriction and ischemia to vital organs, particularly in patients with extensive peripheral vascular disease.

Disease-related concerns:

• Acidosis: Acidosis may reduce the efficacy of phenylephrine; correct acidosis prior to or during use of phenylephrine.

• Autonomic dysfunction: Patients with autonomic dysfunction (eg, spinal cord injury) may exhibit an exaggerated increase in blood pressure response to phenylephrine.

• Hyperthyroidism: Use with caution in patients with hyperthyroidism.

Concurrent drug therapy issues:

• Extravasation: IV administration: Vesicant; ensure proper needle or catheter placement prior to and during infusion. Avoid extravasation.

• Monoamine oxidase inhibitors (MAO-I): Use with extreme caution in patients taking MAO inhibitors; hypertension may result from concurrent use.

Dosage form specific issues:

• Benzyl alcohol and derivatives: Some dosage forms may contain sodium benzoate/benzoic acid; benzoic acid (benzoate) is a metabolite of benzyl alcohol; large amounts of benzyl alcohol (≥99 mg/kg/day) have been associated with a potentially fatal toxicity (“gasping syndrome”) in neonates; the “gasping syndrome” consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension, and cardiovascular collapse (AAP ["Inactive" 1997]; CDC 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors 2001); avoid or use dosage forms containing benzyl alcohol derivative with caution in neonates. See manufacturer’s labeling.

• Oral: When used for self-medication (OTC), use with caution in patients with asthma, bowel obstruction/narrowing, hyperthyroidism, diabetes mellitus, cardiovascular disease, ischemic heart disease, hypertension, increased intraocular pressure, prostatic hyperplasia or in the elderly. Notify healthcare provider if symptoms do not improve within 7 days or are accompanied by fever. Discontinue and contact healthcare provider if nervousness, dizziness, or sleeplessness occur.

• Sulfites: Some products contain sulfites which may cause allergic reactions in susceptible individuals.

Other warnings/precautions:

• Appropriate use: When used intravenously in patients who are hypotensive, assure adequate circulatory volume to minimize need for vasoconstrictors.

• Trained personnel: [US Boxed Warning]: Intravenous preparations should be administered by adequately trained individuals familiar with its use.

Monitoring Parameters

Blood pressure (or mean arterial pressure), heart rate; cardiac output (as appropriate), intravascular volume status, pulmonary capillary wedge pressure (as appropriate); monitor infusion site closely

Consult individual institutional policies and procedures.

Pregnancy Risk Factor

C

Pregnancy Considerations

Animal reproduction studies have not been conducted. Phenylephrine crosses the placenta at term. Maternal use of phenylephrine during the first trimester of pregnancy is not strongly associated with an increased risk of fetal malformations; maternal dose and duration of therapy were not reported in available publications. Phenylephrine is available over-the-counter (OTC) for the symptomatic relief of nasal congestion. Decongestants are not the preferred agents for the treatment of rhinitis during pregnancy. Oral phenylephrine should be avoided during the first trimester of pregnancy; short-term use (<3 days) of intranasal phenylephrine may be beneficial to some patients although its safety during pregnancy has not been studied. Phenylephrine injection is used at delivery for the prevention and/or treatment of maternal hypotension associated with spinal anesthesia in women undergoing cesarean section. Phenylephrine may be associated with a more favorable fetal acid base status than ephedrine; however, overall fetal outcomes appear to be similar. Nausea or vomiting may be less with phenylephrine than ephedrine but is also dependent upon blood pressure control. Phenylephrine may be preferred in the absence of maternal bradycardia.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience insomnia, agitation, nausea, vomiting, or sweating a lot. Have patient report immediately to prescriber angina, tachycardia, passing out, arrhythmia, severe dizziness, severe headache, severe anxiety, urinary retention, change in amount of urine passed, tremors, blurred vision, shortness of breath, excessive weight gain, swelling of arms or legs, bradycardia, burning or numbness of hands or feet, or severe injection site pain or irritation (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

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