Phenylephrine

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Administration of a 10% solution of phenylephrine hydrochloride to patients pretreated with 2% pilocarpine hydrochloride produces mydriasis but to a lesser degree than occurs in patients who are not receiving the miotic. Pilocarpine may prevent or reduce visual disturbances and the risk of increased intraocular pressure associated with mydriasis in some patients and may be used to hasten recovery from mydriasis after ophthalmologic examination. Phenylephrine may reduce ciliary and conjunctival congestion and accommodative myopia often encountered when miotics are used alone in the treatment of glaucoma, without compromising the effectiveness of glaucoma therapy.

Concomitant administration of phenylephrine with cycloplegic antimuscarinic drugs such as atropine sulfate, cyclopentolate hydrochloride, homatropine hydrobromide, or scopolamine hydrobromide produces increased dilation of the pupil which is of clinical value.

The possibility that digitalis can sensitize the myocardium to the effects of sympathomimetic drugs should be considered.

The cardiac and pressor effects of phenylephrine are potentiated by prior administration of monoamine oxidase (MAO) inhibitors because the metabolism of phenylephrine is reduced. The potentiation is greater following oral administration of phenylephrine than after parenteral administration of the drug because reduction of the metabolism of phenylephrine in the intestine results in increased absorption of the drug. Oral administration of phenylephrine to patients receiving a MAO inhibitor should be avoided. Parenteral administration of phenylephrine to these patients, if unavoidable, should be undertaken with extreme caution and initial doses should be small. Patients should consult a clinician before initiating anorectal phenylephrine therapy if they are receiving an MAO inhibitor.

For more Interactions (Complete) data for PHENYLEPHRINE (12 total), please visit the HSDB record page.

The most frequently reported adverse reactions of phenylephrine comprise nausea, vomiting, headache, and nervousness in patients while awake. Due to its selective alpha-receptor stimulation, phenylephrine can induce baroreceptor-mediated reflex bradycardia. In cases of bradycardia and hypotension, healthcare providers should contemplate various classes of vasopressor medications. In specific patient populations, primarily hypovolemic patients with cardiac dysfunction, phenylephrine has the potential to elevate afterload more than preload, leading to reduced cardiac output and potentially worsening conditions such as angina, heart failure, and pulmonary hypertension.

Currently, there is no known antidote for IV phenylephrine. Hypertension resulting from excessive dosing or an exaggerated response is typically transient, primarily due to the short duration of action. The treatment for hypertension or symptomatic reflex bradycardia involves discontinuing the administration of phenylephrine and administering chronotropic agents or vasodilators as necessary. The treatment for tissue extravasation resulting from peripherally administered phenylephrine primarily involves supportive care, including fluid aspiration, warming, and elevation. In some cases, subcutaneous phentolamine can also be considered.

The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical. /Phenylephrine hydrochloride/ [http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=61-76-7]

/SIGNS AND SYMPTOMS/ Overdosage of phenylephrine may cause hypertension, headache, seizures, cerebral hemorrhage, palpitation, paresthesia, or vomiting. Headache may be a symptom of hypertension. Hypertension may be relieved by administration of an alpha-adrenergic blocking agent (e.g., phentolamine). If phenylephrine is administered by rapid IV injection ... overdosage may result in short paroxysms of ventricular tachycardia, ventricular extrasystoles, or a sensation of fullness in the head.

/SIGNS AND SYMPTOMS/ Severe and sometimes fatal cardiovascular reactions, including ventricular arrhythmias and myocardial infarction, have occurred rarely following topical application of 10% phenylephrine hydrochloride ophthalmic solutions; these reactions have occurred most frequently in geriatric patients with preexisting cardiovascular disease.

/CASE REPORTS/ A 71-year-old woman who had critical cerebral ischemia secondary to a carotid artery occlusion was receiving high-dose intravenous phenylephrine for a trial of hypertensive therapy. While on a maximal dose of phenylephrine she developed prominent positive U waves, which disappeared with the cessation of the drug.

/CASE REPORTS/ Four patients (age range 54-82, 1F 3M) diagnosed with non-arteritic ischemic optic neuropathy experienced acute worsening of visual function after instillation of phenylephrine for dilated funduscopic examination. They experienced decreased visual function immediately or shortly after administration of topical mydriatic drops given in preparation for funduscopy. In all cases one drop each of 2.5% phenylephrine and 0.5-1% tropicamide was used. Three patients had classical risk factors such as hypertension, diabetes, and had a contralateral "disc-at-risk". The female and youngest patient had ischemic optic neuropathy presumed secondary to lupus erythematosus. The time from acute visual loss to presentation to neuro-ophthalmic care ranged from 1-6 days. The time of onset of the decline in visual function varied from 45 minutes (patient with lupus) to 12 hours after instillation of mydriatic drops. Visual acuity at diagnosis ranged from 20/40-20/400. Phenylephrine is a mydriatic with vasoconstrictive properties, which may be absorbed through the cornea, thus yielding non-negligible intraocular concentrations. Vasoconstriction of the watershed posterior ciliary capillary beds may result in further precipitating infarction of already compromised circulatory territories in edematous optic nerves. Because phenylephrine is a known vasoconstrictor in vivo and in vitro, it is more likely to cause deleterious vasoconstriction and an acute decline in visual function in patients with acute ischemic optic neuropathy than tropicamide. ...

For more Human Toxicity Excerpts (Complete) data for PHENYLEPHRINE (11 total), please visit the HSDB record page.

Drug-Induced Liver Injury Severity and Toxicity (DILIst)

Phenylephrine

DILI Positive

DOI:10.1016/j.drudis.2019.09.022

/LABORATORY ANIMALS: Acute Exposure/ The ocular and cardiovascular effects as well as aqueous humor and plasma concentrations of 10% phenylephrine HCl and 1% phenylephrine oxazolidine (prodrug) were compared in cynomolgus monkeys. A volume of 25 microliters of either drug was administered to one eye followed by blood pressure, pulse, and pupillary measurements at 10 min intervals up to 60 minutes. Careful slit lamp examinations of the anterior segment, indirect ophthalmoscopy of the vitreous and retina, and ERGs were performed at 60 minutes. Four plasma determinations of phenylephrine following administration of either drug were made between 5 and 60 minutes. Measurement of phenylephrine in aqueous humor was also determined at 60 minutes following all other measurements. The maximal pupillary dilation after administration of 1% prodrug (mean + s.d. = 4.4 + 0.5 mm, n = 12) was slightly greater than after administration of phenylephrine 10% (mean + s.d. = 3.9 + 0.8 mm, n = 12). The differences in pupillary diameter from 20 through 40 minutes were statistically greater for the prodrug. The greater pupillary diameter at the earlier times resulted in an onset of pupillary dilation approximately 15 minutes earlier for the 1% prodrug. There was no ocular toxicity from either drug. Neither drug resulted in any ERG changes compared to baseline. Significantly higher aqueous humor levels along with lower plasma levels were detected and found to be statistically different following administration of the 1% prodrug when compared to 10% phenylephrine.[Schoenwald RD et al; J Ocul Pharmacol 3 (4): 333-40 (1987)]

/LABORATORY ANIMALS: Acute Exposure/ The present study aims to characterize the evolution of the expression of typical leukocyte markers immunohistochemically as correlated to the promotion of PIN lesions. Adolescent rats received injections of phenylephrine (subcutaneously) (10 mg/kg BW/per day) and were euthanized 3, 8 hr, 1, 3, 7, 14 days thereafter. The dissected prostates were fixed in formalin, and paraffin embedded sections were cut and immunoreacted. Phenylephrine exerted a time related bi-phasic effect on the rat prostate. A first inflammatory reaction phase took place at 3-8 hr post injection characterized by vascular dilatation, congestion, edema, and massive leukocytic infiltrate, mainly of ED1+ cells. At 24 hr, the amount of ED1+ cells decreased approaching the equivalent values of ED2+, CD8+ cells, and mastocytes. Their values remained relatively high for the rest of the experimental period. A second phase of proliferative changes, consisting of healing fibrosis as well as dysplastic epithelial lesions, similar to human PIN lesions, appeared on the 7th day. Neuro-immune interactions promote prostatic fibrosis and dysplastic changes; these being preceded by an acute and transient inflammatory reaction.[Rosenzweig N et al; Prostate 59 (1): 107-13 (2004)]

/LABORATORY ANIMALS: Acute Exposure/ The relationship between the pressor and cerebral protective effects of the alpha-adrenergic agonist phenylephrine was assessed. Sprague-Dawley rats were anesthetized and underwent right carotid artery ligation and placement of arterial and central venous pressure catheters and EEG electrodes. Following a two-hour recovery, the rats were exposed to hypoxia (4.5% chamber O2). Three groups of rats were infused with phenylephrine hydrochloride at 17, 35, and 88 micrograms/kg/min, respectively. A fourth group received normal saline, and a fifth, no infusion. All rats receiving phenylephrine experienced an initial pressor response to 130, 162, and 180 mm Hg, respectively, compared with control animals (119 mm Hg). Cerebral electrical activity was prolonged with the two lower doses of phenylephrine (24 +/- 3 minutes and 21 +/- 4 minutes, respectively), compared with the control response (13 +/- 1 minutes). High-dose phenylephrine decreased survival time (8 +/- 1 minutes), despite higher BP at the time of brain death.[Stirling MS et al; Arch Surg 119 (4): 415-8 (1984)]

Phenylephrine generally is contraindicated for ophthalmic use in patients with angle-closure glaucoma and is contraindicated in those with known hypersensitivity to phenylephrine or other components of the commercially available solutions or in those with aneurysm.

The drug should be used with caution in patients with marked hypertension, cardiac disorders, advanced arteriosclerotic changes, type 1 (insulin-dependent, IDDM) diabetes mellitus, or hyperthyroidism; in children of low body weight; and in geriatric patients.

Unless otherwise directed by a clinician, patients should not receive external or rectal preparations of vasoconstrictors such as phenylephrine hydrochloride for self-medication of hemorrhoidal symptoms if they have cardiac disease, high blood pressure, thyroid disease, diabetes mellitus, or difficulty in urination secondary to prostatic hyperplasia. /Phenylephrine hydrochloride/

The drug should be administered with extreme caution to geriatric or hyperthyroid patients or those with bradycardia, partial heart block, myocardial disease, or severe arteriosclerosis. Some clinicians, however, consider severe coronary disease or cardiovascular disease (including myocardial infarction) to be contraindications to use of phenylephrine. Phenylephrine should be administered parenterally with extreme caution if at all to hypertensive patients. Phenylephrine is contraindicated in patients with severe hypertension or ventricular tachycardia and in patients who are hypersensitive to the drug. If administered to patients with acute pancreatitis or hepatitis, the drug may increase ischemia in the liver or pancreas. Phenylephrine should not be used in patients with peripheral or mesenteric vascular thrombosis, because ischemia may be increased and the area of infarction extended.

Emergency and Supportive Measures: Maintain an open airway and assist ventilation if necessary. Administer supplemental oxygen. Treat hypertension aggressively. Treat seizures and ventricular tachyarrhythmias if they occur. Do not treat reflex bradycardia except indirectly by lowering blood pressure. Monitor the vital signs and ECG for a minimum of 4-6 hours after exposure and longer if a sustained-release preparation has been ingested. /Pseudoephedrine, phenylephrine, and other decongestants/

Specific Drugs and Antidotes: Hypertension. Treat hypertension if the diastolic pressure is higher than 100-105 mm Hg, especially in a patient with no prior history of hypertension. If there is CT or obvious clinical evidence of intracranial hemorrhage, lower the diastolic pressure cautiously to no lower than 90 mm Hg and consult a neurosurgeon immediately. Use a vasodilator such as phentolamine or nitroprusside. Caution: Do not use beta blockers to treat hypertension without first giving a vasodilator; otherwise, paradoxic worsening of the hypertension may result. Many patients have moderate orthostatic variation in blood pressure; therefore, for immediate partial relief of severe hypertensin, try placing the patient in an upright position. Arrhythmias. Tachyarrhythmias usually respond to low-dose esmolol for metoprolol. Caution: Do not treaT AV block or sinus bradycardia associated with hypertension; increasing the heart rate with atropine may abolish this reflex response that serves to limit hypertension, resulting in worsening elevation of the blood pressure. /Pseudoephedrine, phenylephrine, and other decongestants/

Decontamination. Administer activated charcoal orally if conditions are appropriate. Gastric lavage is not necessary after small to moderate ingestions if activated charcoal can be given promptly. /Pseudoephedrine, phenylephrine, and other decongestants/

Enhanced Elimination. Dialysis and hemoperfusion are not effective. Urinary acidification may enhance elimination of phenylpropanolamine, ephedrine, and pseudoephedrine but may also aggravate myoglobin deposition in the kidney if the patient has rhabdomyolysis. /Pseudoephedrine, phenylephrine, and other decongestants/

Carcinogenesis studies of USP grade phenylephrine hydrochloride were conducted by administering diets containing the chemical (99% pure) to F344/N rats and B6C3F1 mice of each sex ... for 2 yr. ... Doses of 0, 620, and 1,250 ppm for rats and 0, 1,250, and 2,500 ppm for mice. ... In the 2 yr studies, the approx amount of /cmpd/ consumed per day was 24 mg/kg for low dose rats, 50 mg/kg for high dose rats, 133 mg/kg for low dose mice, and 270 mg/kg for high dose mice. ... Under the conditions of these 2 yr studies, there was no evidence of carcinogenicity of phenylephrine hydrochloride for male or female F344/N rats given 620 or 1,250 ppm in feed or for male or female B6C3F1 mice given 1,250 or 2,500 ppm in feed. ... /Phenylephrine hydrochloride/

Phenylephrine hydrochloride was not mutagenic in four strains of Salmonella typhimurium (TA100, TA1535, TA1537, and TA98) with or without Aroclor 1254-induced liver S9 from male Sprague-Dawley rats or male Syrian hamsters. The results of mutagenicity studies of phenylephrine hydrochloride were equivocal in the mouse lymphoma L5178Y/TK+/- assay in the absence of S9; it was not tested in the presence of S9. Phenylephrine hydrochloride induced sister-chromatid exchanges (SCEs) but not chromosomal aberrations in Chinese hamster ovary cells. The increase in SCEs was seen only in the absence of metabolic activation with S9.

◉ Summary of Use during Lactation

◈ What is phenylephrine?

The Approved Drug Products with Therapeutic Equivalence Evaluations List identifies currently marketed prescription drug products, incl phenylephrine hydrochloride, approved on the basis of safety and effectiveness by FDA under sections 505 of the Federal Food, Drug, and Cosmetic Act. /Phenylephrine Hydrochloride/

Drug products containing certain active ingredients offered over-the-counter (OTC) for certain uses. A number of active ingredients have been present in OTC drug products for various uses, as described below. However, based on evidence currently available, there are inadequate data to establish general recognition of the safety and effectiveness of these ingredients for the specified uses: phenylephrine hydrochloride (less than 0.08 percent) is included in ophthalmic vasoconstrictor drug products. /Phenylephrine hydrochloride/

Nasal decongestant active active ingredients. The active ingredient of the product consists of any of the following when used in the dosage limits and in the dosage forms established for each ingredient. Oral nasal decongestants: phenylephrine hydrochloride, phenylephrine bitartrate in an effervescent dosage form. Topical nasal decongestants: Phenylephrine hydrochloride. /Phenylephrine hydrochloride; Phenylephrine bitartrate/

Vasoconstrictor active ingredients. The active ingredient of the product consists of any of the following when used in the concentration or within the concentration range established for each ingredient. Phenylephrine hydrochloride 0.25 percent.

Ophthalmic vasoconstrictors. The active ingredient of the product consists of one of the following, within the established concentration for each ingredient. Phenylephrine hydrochloride, 0.08 to 0.2 percent.

Sympathomimetic vasoconstructor amine ... used for nasal congestion /Hydrochloride/

... used to dilate the pupil both for ophthalmoscopy in the treatment of uveitis and for cataract surgery /Hydrochloride/

MEDICATION

THERAP CAT: Mydriatic; decongestant; in treatment of fecal incontinence.

Use (kg; approx.) in Germany (2009): >100

(1976) 1.30X10+6 G (PRINCPL CUSTMS DISTS)

(1978) 4.43X10+6 G (PRINCPL CUSTMS DISTS)

(1976) PROBABLY GREATER THAN 9.08X10+5 G

(1978) PROBABLY GREATER THAN 9.08X10+5 G

(1988) No data published for phenylephrine (bitartrate, hydrochloride, tannate)

REACTION OF M-HYDROXYPHENACYL BROMIDE WITH METHYLAMINE FOLLOWED BY CATALYTIC HYDROGENATION, THEN DISSOLUTION IN ETHER, AND TREATMENT WITH HYDROGEN CHLORIDE

Preparation: H. Legerlotz, US 1932347 (1933 to Frederick Stearns)

M-HYDROXYPHENACYL BROMIDE IS CONDENSED WITH METHYLAMINE VIA DEHYDROBROMINATION & CARBONYL GROUP IS THEN REDUCED TO CARBINOL VIA CATALYTIC HYDROGENATION. PHENYLEPHRINE SO FORMED IS DISSOLVED IN SUITABLE SOLVENT SUCH AS ETHER & TREATED WITH HYDROGEN CHLORIDE. /PHENYLEPHRINE HYDROCHLORIDE/

Oral: Strips, orally dissolving: 1.25 mg Triaminic Infant Thin Strips Decongestant, (Novartis) 2.5 mg Triaminic Thin Strips Cold, (Novartis). Tablets: 10 mg Sudafed PE, (Pfizer). Parenteral: Injection: 10 mg/mL Neo-Synephrine Hydrochloride (with sodium metabisulfite), (Sanofi-Aventis), Phenylephrine Hydrochloride Injection, (American Regent), Phenylephrine Hydrochloride Injection, (Baxter). Topical: Cream: 0.25% with Glycerin 12%, (Petrolatum); 18%, and Shark Liver Oil 3% Preparation H (with cetyl alcohol, methylparaben, and stearyl alcohol), (Wyeth). Gel: 0.25% with Witch Hazel 50% Preparation H (with methylparaben and propylparaben), (Wyeth). Ointment: 0.25% with Mineral Oil 14%, Petrolatum 71.9%, and Shark Liver Oil 3% Preparation H (with methylparaben and propylparaben), (Wyeth). Suppository: 0.25% with Cocoa Butter 85.5% and Shark Liver Oil 3% Preparation H (with methylparaben and propylparaben), (Wyeth).

Nasal: Solution: 0.25% Neo-Synephrine Mild Formula Spray (with benzalkonium chloride), (Bayer); 0.5% Neo-Synephrine Regular Strength (with benzalkonium chloride; drops and spray), (Bayer), Vicks Sinex for Sinus Relief (with benzalkonium chloride; regular or metered pump mist spray), (Procter & Gamble); 1% Neo-Synephrine Extra Strength (with benzalkonium chloride; drops and spray), (Bayer). Ophthalmic: Solution: 0.12% Ocu-Phrin, Ocumed Relief (with benzalkonium chloride), (Allergan); 2.5% AK-Dilate (with benzalkonium chloride and sodium bisulfite), (Akorn), Mydfrin (with benzalkonium chloride and sodium bisulfite), (Alcon) Neo-Synephrine Hydrochloride (with benzalkonium chloride), (Sanofi-Aventis), Ocu-Phrin, (Ocumed); 10% AK-Dilate (with benzalkonium chloride and sodium bisulfite), (Akorn), Neo-Synephrine Hydrochloride (with benzalkonium chloride; plain and viscous), (Sanofi-Aventis), Ocu-Phrin, (Ocumed). Parenteral: Injection: 10 mg/mL Neo-Synephrine Hydrochloride (with sodium metabisulfite), (Sanofi-Aventis), Phenylephrine Hydrochloride Injection, (American Regent), Phenylephrine Hydrochloride Injection, (Baxter). /Phenylephrine hydrochloride/

Ophthalmic: Solution: 0.12% Ocu-Phrin, (Ocumed), Relief (with benzalkonium chloride; viscous), (Allergan); 2.5% AK-Dilate (with benzalkonium chloride and sodium bisulfite), (Akorn), Mydfrin (with benzalkonium chloride and sodium bisulfite), (Alcon), Neo-Synephrine Hydrochloride (with benzalkonium chloride), (Sanofi-Aventis), Ocu-Phrin, (Ocumed), Phenylephrine Hydrochloride Ophthalmic Solution, (Bausch & Lomb), Phenylephrine Hydrochloride Ophthalmic Solution, (Falcon); 10% AK-Dilate (with benzalkonium chloride and sodium bisulfite), (Akorn), Neo-Synephrine Hydrochloride (with benzalkonium chloride; plain and viscous), (Sanofi-Aventis), Ocu-Phrin, (Ocumed). /Phenylephrine hydrochloride/