What are the uses of phenylephrine medicines. How do phenylephrine medications work. What are the potential side effects of phenylephrine. Who should exercise caution when using phenylephrine products. How should phenylephrine be properly administered.

Understanding Phenylephrine: A Common Decongestant

Phenylephrine is a widely used medication primarily employed as a decongestant. It belongs to a class of drugs known as sympathomimetic amines, which work by stimulating certain receptors in the body to produce specific effects. In the case of phenylephrine, its primary action is to constrict blood vessels in the nasal passages, thereby reducing swelling and congestion.

Why is phenylephrine so commonly used in over-the-counter cold and allergy medications? The answer lies in its effectiveness in providing relief from nasal congestion without causing significant drowsiness, a side effect often associated with some other decongestants. This makes phenylephrine a preferred choice for those who need to remain alert during the day while managing cold or allergy symptoms.

Primary Uses of Phenylephrine in Medicine

Phenylephrine serves multiple purposes in the medical field, with its most common applications being:

• Relieving nasal congestion
• Alleviating sinus pressure
• Reducing ear discomfort associated with congestion
• Treating symptoms of the common cold and flu
• Managing allergy-related nasal symptoms
• Addressing congestion related to sinusitis and bronchitis

How does phenylephrine achieve these effects? The medication works by constricting blood vessels in the nasal passages and surrounding areas. This constriction reduces blood flow to these tissues, which in turn decreases swelling and fluid accumulation. As a result, breathing becomes easier and discomfort is reduced.

Administration and Dosage Guidelines for Phenylephrine

Proper administration of phenylephrine is crucial for its effectiveness and safety. The medication is available in various forms, including tablets, liquids, and nasal sprays. When using oral formulations:

1. Always follow the dosage instructions on the product label or as prescribed by your healthcare provider.
2. Take the medication with or without food. If stomach upset occurs, taking it with food may help.
3. Use a proper measuring device for liquid formulations to ensure accurate dosing.
4. For chewable tablets, thoroughly chew before swallowing.
5. Orally dissolving tablets or strips should be allowed to dissolve completely on the tongue before swallowing.

Is there a maximum duration for using phenylephrine? Generally, it’s recommended not to use phenylephrine for more than 7 consecutive days without consulting a healthcare professional. Prolonged use may lead to rebound congestion or other complications.

Dosage Considerations for Different Age Groups

Dosage requirements for phenylephrine can vary based on age and specific formulation. It’s important to note that:

• Children under 6 years old should not use phenylephrine-containing products unless specifically directed by a doctor.
• Some long-acting formulations are not recommended for children under 12 years old.
• Adults and children 12 years and older typically follow the standard dosage instructions provided on the product label.

Why are there age restrictions on phenylephrine use? These guidelines are in place due to the potential for serious side effects in young children and the lack of conclusive evidence regarding the safety and efficacy of cough and cold medications in this age group.

Potential Side Effects and Risks of Phenylephrine

While phenylephrine is generally considered safe when used as directed, it can cause various side effects. Common side effects may include:

• Mild stomach upset
• Insomnia or difficulty sleeping
• Dizziness or lightheadedness
• Headache
• Nervousness or anxiety
• Tremors or shaking
• Increased heart rate

Can phenylephrine cause more serious side effects? While rare, some individuals may experience severe adverse reactions, including:

• Irregular or rapid heartbeat
• Severe uncontrolled shaking
• Difficulty urinating
• Seizures
• Mental or mood changes (such as confusion or unusual thoughts/behavior)
• Allergic reactions (rash, itching, swelling, severe dizziness, trouble breathing)

If any of these serious side effects occur, it’s crucial to seek immediate medical attention. Always report any unusual or persistent side effects to your healthcare provider.

Precautions and Contraindications for Phenylephrine Use

Before using phenylephrine, it’s essential to consider certain precautions and potential contraindications. Individuals with the following conditions should exercise caution or avoid using phenylephrine unless directed by a healthcare professional:

• High blood pressure
• Heart disease (including angina, arrhythmias, or heart failure)
• Diabetes
• Glaucoma
• Thyroid disorders
• Enlarged prostate
• Blood vessel problems (such as Raynaud’s disease)
• Mental health conditions (including anxiety or bipolar disorder)

Why are these precautions necessary? Phenylephrine can potentially exacerbate these conditions due to its effects on blood vessels and its stimulant properties. For instance, it may increase blood pressure or interfere with blood sugar control in diabetics.

Interactions with Other Medications

Phenylephrine can interact with various medications, potentially altering their effectiveness or increasing the risk of side effects. Some important interactions to be aware of include:

• Monoamine oxidase inhibitors (MAOIs)
• Certain antidepressants
• Beta-blockers
• Other decongestants or stimulants
• Some blood pressure medications

Always inform your healthcare provider about all medications, supplements, and herbal products you are taking before using phenylephrine. This helps prevent potentially dangerous drug interactions.

Special Considerations for Phenylephrine Use During Pregnancy and Breastfeeding

The use of phenylephrine during pregnancy and breastfeeding requires careful consideration. While limited data is available, here are some key points to consider:

Pregnancy

Is phenylephrine safe during pregnancy? The FDA classifies phenylephrine as a Pregnancy Category C drug, meaning that animal studies have shown an adverse effect on the fetus, but there are no adequate studies in humans. The potential benefits may warrant use of the drug in pregnant women despite potential risks. Always consult with a healthcare provider before using phenylephrine during pregnancy.

Breastfeeding

Can phenylephrine be used while breastfeeding? Small amounts of phenylephrine may pass into breast milk, but the effects on nursing infants are not well-studied. As with pregnancy, it’s crucial to consult a healthcare provider before using phenylephrine while breastfeeding. They can help weigh the potential risks and benefits based on individual circumstances.

Proper Storage and Disposal of Phenylephrine Products

To maintain the effectiveness and safety of phenylephrine products, proper storage and disposal are essential. Here are some guidelines to follow:

Storage

• Keep phenylephrine products at room temperature, away from direct sunlight and moisture.
• Store in a cool, dry place unless otherwise directed on the product label.
• Keep out of reach of children and pets.
• Do not store in the bathroom, as humidity can affect the medication.

Disposal

How should unused or expired phenylephrine products be disposed of? Follow these steps:

1. Check if your local pharmacy has a medication take-back program.
2. If no take-back program is available, mix the medication with an undesirable substance (like used coffee grounds or cat litter) in a sealed plastic bag before throwing it in the trash.
3. Remove or obscure any personal information on the empty medication container before disposing of it.

Proper disposal helps prevent accidental ingestion by children or pets and reduces environmental contamination.

Alternatives to Phenylephrine for Nasal Congestion Relief

While phenylephrine is a popular choice for treating nasal congestion, it’s not the only option available. For those who may not be able to use phenylephrine or prefer alternatives, consider the following:

Other Decongestants

• Pseudoephedrine: An effective oral decongestant, but requires ID for purchase in many countries due to its potential use in illegal drug manufacturing.
• Oxymetazoline: A nasal spray decongestant, but should not be used for more than 3 days to avoid rebound congestion.

Non-Medicinal Alternatives

• Saline nasal sprays or rinses: Help to moisturize nasal passages and flush out irritants.
• Steam inhalation: Can provide temporary relief by moistening and clearing nasal passages.
• Nasal strips: Mechanical aids that help open nasal passages for easier breathing.
• Humidifiers: Increase moisture in the air, which can help relieve congestion.

Natural Remedies

Are there natural alternatives to phenylephrine? Some people find relief with:

• Eucalyptus oil: When inhaled, may help clear nasal passages.
• Peppermint tea: The menthol in peppermint can have a mild decongestant effect.
• Ginger and turmeric: Both have anti-inflammatory properties that may help reduce nasal swelling.

It’s important to note that while these alternatives may provide relief for some individuals, their effectiveness can vary. Always consult with a healthcare provider before trying new treatments, especially if you have underlying health conditions or are taking other medications.

The Future of Decongestant Medications: Research and Development

As medical science continues to advance, researchers are constantly exploring new ways to improve decongestant medications. Some areas of focus in current research include:

Novel Drug Delivery Systems

Scientists are investigating innovative methods to deliver decongestants more effectively and with fewer side effects. These may include:

• Targeted nasal delivery systems that provide localized relief without systemic effects
• Long-acting formulations that require less frequent dosing
• Combination therapies that address multiple symptoms simultaneously

Alternative Mechanisms of Action

Researchers are exploring new compounds that may relieve congestion through different physiological pathways. This could potentially lead to decongestants with improved efficacy and safety profiles.

Personalized Medicine Approaches

How might decongestant treatments become more tailored to individual needs? Future developments may include:

• Genetic testing to determine the most effective decongestant for each person
• Customized formulations based on an individual’s specific symptoms and medical history
• Smart delivery systems that adjust dosage based on real-time physiological data

While these advancements are still in various stages of research and development, they hold promise for improving the treatment of nasal congestion and related symptoms in the future.

Understanding the Regulatory Landscape for Phenylephrine Products

The regulation of phenylephrine products varies across different countries and regions. In many places, including the United States, phenylephrine is available over-the-counter (OTC) for nasal congestion relief. However, the regulatory landscape is not static and can change based on new research findings and safety considerations.

Current Regulatory Status

In the United States, the Food and Drug Administration (FDA) oversees the regulation of phenylephrine products. Key points about its current regulatory status include:

• OTC availability for nasal congestion relief
• Restrictions on marketing claims and labeling
• Ongoing safety monitoring and periodic reviews

Recent Developments and Future Outlook

Are there any potential changes on the horizon for phenylephrine regulation? Some recent developments and areas of focus include:

• Reassessment of efficacy: Some studies have questioned the effectiveness of oral phenylephrine at currently approved doses, potentially leading to future regulatory reviews.
• Safety in specific populations: Ongoing research into the safety of phenylephrine in certain groups, such as children and the elderly, may influence future regulatory decisions.
• International harmonization efforts: There’s a trend towards aligning regulatory approaches across different countries, which could impact how phenylephrine is regulated globally.

As with all medications, the regulatory landscape for phenylephrine is subject to change based on emerging scientific evidence and public health considerations. Staying informed about these developments can help consumers and healthcare providers make more informed decisions about the use of phenylephrine products.

The Role of Phenylephrine in Combination Cold and Flu Medications

Phenylephrine is often found as an ingredient in multi-symptom cold and flu medications. These combination products aim to address multiple symptoms simultaneously, potentially offering more comprehensive relief for individuals suffering from colds or flu.

Common Combinations

Phenylephrine is frequently combined with other active ingredients such as:

• Acetaminophen or ibuprofen for pain and fever relief
• Dextromethorphan for cough suppression
• Guaifenesin as an expectorant
• Antihistamines for allergy symptom relief

Benefits and Considerations

What are the advantages and potential drawbacks of these combination products? Let’s examine:

Benefits:

• Convenience of addressing multiple symptoms with a single medication
• Potentially improved compliance due to simplified dosing
• Cost-effectiveness compared to purchasing individual medications

Considerations:

• Increased risk of side effects or drug interactions due to multiple active ingredients
• Possibility of taking unnecessary medications if not all symptoms are present
• Potential for overdosing on certain ingredients if multiple combination products are used

When considering the use of combination products containing phenylephrine, it’s crucial to carefully read labels and only treat symptoms that are actually present. Consulting with a healthcare provider or pharmacist can help ensure safe and appropriate use of these medications.

Phenylephrine Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing

Uses

Phenylephrine is used for the temporary relief of stuffy nose, sinus, and ear symptoms caused by the common cold, flu, allergies, or other breathing illnesses (such as sinusitis, bronchitis). This medication works by decreasing swelling in the nose and ears, thereby lessening discomfort and making it easier to breathe.Cough-and-cold products have not been shown to be safe or effective in children younger than 6 years. Do not use this product to treat cold symptoms in children younger than 6 years unless specifically directed by the doctor. Some products (such as long-acting tablets/capsules) are not recommended for use in children younger than 12 years. Ask your doctor or pharmacist for more details about using your product safely.These products do not cure or shorten the length of the common cold and may cause serious side effects. To decrease the risk for serious side effects, carefully follow all dosage directions. Do not use this product to make a child sleepy. Do not give other cough-and-cold medication that might contain the same or similar ingredients (see also Drug Interactions section). Ask the doctor or pharmacist about other ways to relieve cough and cold symptoms (such as drinking enough fluids, using a humidifier or saline nose drops/spray).

How to use Phenylephrine 10 Mg Tablet Oral Decongestants

If you are using the over-the-counter product, read and follow all directions on the product package before taking this medication.

Take this medication by mouth with or without food or as directed by your doctor. Taking it with food may decrease stomach upset.

If you are using the liquid, carefully measure your prescribed dose using a medication-measuring device or spoon. Do not use a household spoon because you may not get the correct dose.

If you are using chewable tablets, chew each tablet thoroughly before swallowing.

If you are using a product made to dissolve in the mouth (tablets or strips), dry your hands before handling the medication. Place each dose on the tongue and allow to dissolve completely, then swallow it with saliva or with water.

The dosage is based on your age. Do not increase your dose or take this medication more often than directed without your doctor’s approval. Improper use (abuse) of this medication may result in serious harm (such as hallucinations, seizure, death).

If your symptoms worsen or do not improve after 7 days, if you develop fever/chills, or if you think you may have a serious medical problem, get medical help right away.

Side Effects

Mild upset stomach, trouble sleeping, dizziness, lightheadedness, headache, nervousness, shaking, or fast heartbeat may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

This product may reduce blood flow to your hands or feet, causing them to feel cold. Smoking may worsen this effect. Dress warmly and avoid tobacco use.

If your doctor has directed you to use this medication, remember that your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: fast/irregular heartbeat, severe/uncontrolled shaking, difficulty urinating, seizures, mental/mood changes (such as anxiety, panic, confusion, unusual thoughts/behavior).

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US – Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Precautions

Before taking phenylephrine, tell your doctor or pharmacist if you are allergic to it; or to pseudoephedrine/ephedrine; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: blood vessel problems (such as Raynaud’s disease, low blood flow to the brain/legs/hands), high blood pressure, diabetes, glaucoma, heart disease (such as angina, fast/irregular heartbeat, heart failure), mental/mood disorders (such as anxiety, bipolar disorder, mania), difficulty sleeping, seizure disorder, overactive thyroid (hyperthyroidism), trouble urinating (such as due to enlarged prostate).

This drug may make you dizzy or lightheaded. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Liquid products, chewable tablets, or dissolving tablets/strips may contain sugar or aspartame. Liquid products may also contain alcohol. Caution is advised if you have diabetes, alcohol dependence, liver disease, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using this product safely.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Older adults may be more sensitive to the side effects of this drug, especially fast/irregular heartbeat, dizziness, problems urinating, trouble sleeping, or confusion.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication may pass into breast milk. Though there have been no reports of harm to nursing infants, consult your doctor before breast-feeding.

Interactions

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor’s approval.

Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, metaxalone, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before treatment with this medication. Ask your doctor when to start or stop taking this medication.

Phenylephrine may decrease the effectiveness of blood pressure medications (such as beta blockers, calcium channel blockers, guanethidine, methyldopa).

Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain similar ingredients (decongestants such as pseudoephedrine). Ask your pharmacist about using those products safely.

This medication may worsen the serious side effects of some medications used for migraine headaches (such as sumatriptan, naratriptan, zolmitriptan, ergotamine). Consult your pharmacist or doctor for more details.

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Overdose

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe dizziness/fainting, hallucinations, fast/irregular heartbeat, slow/shallow breathing, vomiting, seizures.

If this product has been prescribed, do not share this medication with others.

This medication is for temporary use only. Do not use for more than 7 days in a row without first consulting your doctor.

If you are taking this medication on a prescribed schedule and miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

Phenylephrine – StatPearls – NCBI Bookshelf

Continuing Education Activity

The FDA-approved indication for intravenous (IV) phenylephrine hydrochloride is for increasing blood pressure in adults with clinically significant hypotension resulting primarily from vasodilation in such settings as septic shock or anesthesia. Phenylephrine HCL is also used over-the-counter in ophthalmic formulations to promote mydriasis and conjunctival blood vessel vasoconstriction, intranasal administration as a treatment for uncomplicated nasal congestion, and as an over-the-counter additive to topical hemorrhoid medications. This activity outlines the indications, mechanism of action, methods of administration, important adverse effects, contraindications, dose forms, monitoring, and toxicity of phenylephrine, so providers can direct patient therapy in treating the various conditions for which it is indicated, as part of the interprofessional team.

Objectives:

• Identify the mechanism of action of phenylephrine therapy.

• Describe a hypotensive patient that would be most suitable for phenylephrine therapy based on known hemodynamics.

• Review the adverse event profile and contraindications of phenylephrine.

• Outline interprofessional team strategies for improving care coordination and communication to advance phenylephrine therapy and improve outcomes.

Access free multiple choice questions on this topic.

Indications

The FDA-approved indication for intravenous (IV) phenylephrine hydrochloride is for increasing blood pressure in adults with clinically significant hypotension resulting primarily from vasodilation in such settings as septic shock or anesthesia. Phenylephrine HCL is also used over-the-counter in ophthalmic formulations to promote mydriasis and conjunctival blood vessel vasoconstriction, intranasal administration as a treatment for uncomplicated nasal congestion, and as an over-the-counter additive to topical hemorrhoid medications.[1] Phenylephrine is less commonly used off-label as an additive to neuraxial/peripheral nerve blockade, to treat priapism and other conditions where local vasoconstrictive effects and reduced blood flow are the desired effect. In the setting of IV administration, phenylephrine is a commonly used anesthetic vasopressor for patients with normal cardiac function and hypotension secondary to the vasodilatory effect of anesthetic medications or non-cardiac shock states.

Phenylephrine is primarily an alpha-1 adrenergic receptor agonist with minimal to no beta-adrenergic activity; therefore, it is ideal for elevating mean arterial pressure. It does so by causing venous and arterial vasoconstriction and increasing cardiac preload without having any significant direct effect on cardiac myocytes.[2] Hypotension during general and neuraxial anesthesia remains one of the most commonly encountered problems for the anesthetic provider and must be addressed rapidly to avoid prolonged hypoperfusion states.[3] During any given surgical procedure, blood pressure can vary considerably based upon the patient’s underlying pathology, the dosage of anesthetic medications, volume status, the degree of surgical stimulation, and the presence of other blood pressure modulating medications. Vasopressor medications with short onset, short duration of action, and predictable dose-dependent responses such as phenylephrine are ideal for treating hypotensive patients.

Phenylephrine has been shown to be effective in offsetting commonly encountered hypotension associated with spinal anesthetics (60% to 70%) in obstetric patients and has become the preferred vasopressor in this setting. [3] Phenylephrine is also used in the intensive care unit (ICU) environment to treat septic and neurogenic shock. With the advent of the surviving sepsis campaign, management of sepsis has undergone more scrutiny and a more standardized approach to septic shock states has been developed with norepinephrine as the vasopressor/inotrope of choice.

Although phenylephrine is not recommended as the initial treatment of septic shock, it is an acceptable therapy in the case of norepinephrine associated arrhythmias, known high cardiac output with hypotension, and as a salvage therapy when combined inotrope and vasopressor drugs when low-dose vasopressin has failed to achieve MAP target.[4] Neurogenic shock secondary to acute traumatic spinal cord injury can similarly produce a systemic vasodilatory state, often in the setting of preserved cardiac output. These injuries frequently require higher target mean arterial pressures (85 to 90 mm Hg) to maintain spinal cord perfusion and reduce secondary injury, making phenylephrine a reasonable and safe choice in the hemodynamic maintenance of these patients. [5]

Mechanism of Action

Phenylephrine is a direct-acting sympathomimetic amine that functions as an alpha-1 adrenergic agonist. Its chemical structure is related to epinephrine and ephedrine and possesses potent vasoconstriction properties when given intravenously or applied directly to mucosal membranes. The overall effect of intravenous phenylephrine on cardiac output and end perfusion is likely more complex and variable based on bolus versus infusion dosing, volume status, baseline heart rate, autonomic tone, and cardiac pathology. These variations are attributable to the degree of venoconstriction which can temporarily increase preload, arterial constriction which will increase systemic vascular resistance and afterload, and the presence of reflex bradycardia leading to an overall mixed effect on cardiac output depending on the patient population.[6][7][8] Regarding ophthalmic administration, phenylephrine binds alpha-1 receptors that innervate the iris dilator muscle yielding smooth muscle contraction and subsequent dilation of the pupil which can assist in fundoscopic exams, exposure in certain surgeries, and treatment of various conditions. [9]

Administration

The most common routes of administration for phenylephrine include oral, topical, intravenous, intranasal, ophthalmic, and rectal. Less commonly, phenylephrine has been administered in the epidural space, as an adjunct to peripheral nerve blockade, in the intracavernous space, intramuscularly, and subcutaneously.[10][11] When administering phenylephrine intravenously, dosing is typically in 50 to 100 mcg aliquots and frequently requires redosing as it has a short onset of action (1 to 3 minutes) and short duration of action (5 to 20 minutes).[12] 

Additionally, phenylephrine dosing can be via weight-based or non-weight based infusion with typical dose ranges of 0.1 to 1.5 mcg/kg per minute.[13] Despite the classic teaching that all vasoactive medications require central venous access to avoid necrosis in the event of tissue extravasation, phenylephrine has demonstrated to be safe and effective when given through peripheral intravenous catheters when dilution, vein, and catheter selection, and frequent site inspection are appropriate. [14] 

Ophthalmic solutions of phenylephrine have a wide range of concentrations and additives depending on the desired effect.  Concentrations utilized by medical professionals generally come in doses of 1%, 2.5%, or 10%. The 1% formulations are often administered in combination with cyclopentolate 0.2% for dilated fundus and cycloplegic exams in newborns of less than three months. The 2.5% formulations are the most commonly used for dilated fundus exams in adults, children over three months, and as an aid in diagnosing conditions such as episcleritis. The 10% formulation is less commonly used (due to fear of systemic absorption) in dilated exams and to provide exposure during surgeries.

Over-the-counter (OTC) preparations of phenylephrine combination drops may come in concentrations as low as 0.12% and are marketed as a treatment of “red-eye” or uncomplicated conjunctivitis. Phenylephrine is available as an FDA-approved, over-the-counter decongestant in oral concentrations of up to 10 mg, nasal solutions typically ranging between 0. 125% to  1% and are found as an additive in various OTC topical hemorrhoid creams.[15][16]

Adverse Effects

The most common adverse reactions include nausea, vomiting, headache, and nervousness in an awake patient. Because of phenylephrine’s sole alpha-receptor stimulation, it can cause baroreceptor-mediated reflex bradycardia. Clinicians should consider different classes of vasopressor medications in the bradycardic, hypotensive patient. In specific patient populations, primarily hypovolemic patients with cardiac dysfunction, phenylephrine can increase afterload more so than preload, causing decreased cardiac output and potentially an exacerbation of angina, heart failure, and pulmonary hypertension.[6]

Contraindications

There are no absolute contraindications to phenylephrine aside from hypersensitivity to the drug or any of its components. Phenylephrine contains sodium metabisulfite, a sulfite that may cause allergic-type reactions, including anaphylactic symptoms or less severe asthmatic episodes in susceptible people. The overall prevalence of sulfite sensitivity is unknown and probably low. Phenylephrine use requires caution in patients with a history of bradycardia, autonomic dysfunction, severe cardiac dysfunction, and hypovolemia.

Monitoring

There are no specific drug monitoring requirements for intravenous phenylephrine; however, vasoactive medications should not be given outside of the perioperative or intensive care settings, or in environments where heart rate/rhythm, blood pressure, and pulse oximetry monitoring are unavailable. Many traditional texts recommend the administration of all vasoactive medications through a central line; however, phenylephrine is routinely given peripherally in the operative setting and has been shown to be safe even in prolonged infusions in 18 to 20 g IV in large veins with frequent site inspections.[14] 

Despite the widespread use of peripherally administered intravenous phenylephrine, a systematic review of published articles involving peripherally administered vasoactive medications and reports of extravasation showed only two cases of skin necrosis in high-risk patients receiving peripherally administered phenylephrine. [17] It is still good practice to administer phenylephrine through central venous catheters when available or via the largest proximal vein possible with frequent inspection and aspiration of blood.

Topical, ophthalmic, and nasal administrations of phenylephrine are typically well-tolerated, but there is always the concern for systemic absorption. Although there have been case reports of hemodynamic instability following the administration of higher concentrations (10%) of ophthalmic phenylephrine, 2.5% concentrations lead to no statistically significant difference in heart rate or blood pressure.[18] Oral and nasal phenylephrine formulation have correlated with case reports of rare adverse events. However, there appears to be no appreciable effect on hemodynamics when administered in standard dosages.[19][15][20][21][22]

Toxicity

Currently, there is no available antidote for intravenous phenylephrine. Hypertension in the setting of excessive dosing or an exaggerated response is usually short-lived due to the short duration of action. The treatment for hypertension or symptomatic reflex bradycardia is discontinuing the administration of phenylephrine and chronotropic agents or vasodilators as needed. Treatment for tissue extravasation of peripherally administered phenylephrine is largely supportive care (aspiration of fluid, warming, elevation), but subcutaneous phentolamine is an option used.[23]

Enhancing Healthcare Team Outcomes

It is worth noting that phenylephrine is often administered in a variety of hospital environments (ICU, operating room [OR], labor and delivery [L and D], emergency room [ER], among others) and may require the participation of various health care providers (pharmacists, nurses, PAs, NPs, CRNAs, and physicians) in its dilution and administration. Manufacturers most commonly provide intravenous phenylephrine in highly concentrated doses (10 mg/ml) that require dilution before administration. Phenylephrine is frequently associated with medication errors and can account to up to 10% of all errors in the perioperative setting. Because of this, pharmacists and nursing, in particular, must maintain an open line of communication to ensure proper dosing and administration.

All providers administering phenylephrine should familiarize themselves with the appropriate dilution.[24] Manufacturer recommendations for the preparation of bolus dosing are to add 10 mg of phenylephrine to 99 mL of 5% dextrose or 0.9% sodium chloride solutions, yielding a 100 mcg/mL concentration. For continuous infusions, the recommendation is that 10 mg of phenylephrine be added to a 500 mL of 5% dextrose or 0.9% sodium chloride solutions, yielding a 20 mcg/mL concentration.

If both pharmacists and nurses are familiar with the correct dosing and dilution, they can serve as a double backstop for the physician, and verify that dosing is appropriate. COmmunicaitonlines should be such that they are free to contact the ordering physician with any concerns.

It is important to remember that although “Rapid Response” and “Code Teams” likely reduce morbidity and mortality, they are composed of members of varying degrees of education and experience. [25][26] Since phenylephrine may be the vasopressor of choice in many emergencies, any potential code team leader should be familiar with and rehearse the direction of its administration. Specific closed-loop communications (“Please dilute a 10-mg vial of phenylephrine in a 100-mL bag of normal saline and administer 2 mL of 100 mcg/mL through the patient’s central line, and let me know when it has been given”, rather than “Please give the patient 200 mcg of phenylephrine.”) have been shown to not only reduce medication errors but to improve time-to-task completion in emergencies significantly.[27] 

The basis of this information is a prospective observational study with intervention level II evidence. It does demonstrate that a collaborative interprofessional team approach is the best means by which to optimize therapy with phenylephrine and prevent medication errors. [Level V]

Review Questions

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References

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Flancbaum L, Dick M, Dasta J, Sinha R, Choban P. A dose-response study of phenylephrine in critically ill, septic surgical patients. Eur J Clin Pharmacol. 1997;51(6):461-5. [PubMed: 9112060]

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Esteve-Taboada JJ, Del Águila-Carrasco AJ, Bernal-Molina P, Ferrer-Blasco T, López-Gil N, Montés-Micó R. Effect of Phenylephrine on the Accommodative System. J Ophthalmol. 2016;2016:7968918. [PMC free article: PMC5174178] [PubMed: 28053778]

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Cheng JK, Pan MH, Wu KH, Mok MS, Wei TT. Epidural phenylephrine attenuates hypotension induced by alkalinized lidocaine epidural anesthesia. Anesth Analg. 1999 Jun;88(6):1322-6. [PubMed: 10357338]

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Ridyard DG, Phillips EA, Vincent W, Munarriz R. Use of High-Dose Phenylephrine in the Treatment of Ischemic Priapism: Five-Year Experience at a Single Institution. J Sex Med. 2016 Nov;13(11):1704-1707. [PubMed: 27692841]

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Lonjaret L, Lairez O, Minville V, Geeraerts T. Optimal perioperative management of arterial blood pressure. Integr Blood Press Control. 2014;7:49-59. [PMC free article: PMC4178624] [PubMed: 25278775]

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Jentzer JC, Coons JC, Link CB, Schmidhofer M. Pharmacotherapy update on the use of vasopressors and inotropes in the intensive care unit. J Cardiovasc Pharmacol Ther. 2015 May;20(3):249-60. [PubMed: 25432872]

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Loubani OM, Green RS. A systematic review of extravasation and local tissue injury from administration of vasopressors through peripheral intravenous catheters and central venous catheters. J Crit Care. 2015 Jun;30(3):653.e9-17. [PubMed: 25669592]

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Stavert B, McGuinness MB, Harper CA, Guymer RH, Finger RP. Cardiovascular Adverse Effects of Phenylephrine Eyedrops: A Systematic Review and Meta-analysis. JAMA Ophthalmol. 2015 Jun;133(6):647-52. [PubMed: 25789577]

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Ah-Kee EY, Li Yim JF. Bilateral acute angle closure glaucoma precipitated by over the counter oral decongestant. Int J Ophthalmol. 2014;7(2):387-8. [PMC free article: PMC4003102] [PubMed: 24790890]

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Hatton RC, Winterstein AG, McKelvey RP, Shuster J, Hendeles L. Efficacy and safety of oral phenylephrine: systematic review and meta-analysis. Ann Pharmacother. 2007 Mar;41(3):381-90. [PubMed: 17264159]

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Disclosure: Evan Richards declares no relevant financial relationships with ineligible companies.

Disclosure: Michael Lopez declares no relevant financial relationships with ineligible companies.

Disclosure: Christopher Maani declares no relevant financial relationships with ineligible companies.

Active substance PHENYLEPHRINE (PHENYLEPHRINUM) | Compendium

Manufacturer:

CAS No: 59-42-7 C ₉ H ₁₃ NO ₂

HSDB, RTECS: (-)-m-hydroxy- α -(methylaminomethyl)benzyl alcohol.

M _m = 167.21 Da. log P (octanol-water) = -0.31. White or white with a slightly yellowish tinge, odorless crystalline powder. Easily soluble in water and alcohol.

Presentation: injection solution, nasal drops, nasal spray, rectal ointment, rectal suppositories.

• Pharmacological properties
• Indications Phenylephrine
• Application of phenylephrine
• Contraindications
• Side effects
• Special instructions
• Diagnosis
• Recommended alternatives
• Trade names

Medicinal preparations containing the active substance PHENYLEFRINE

Irifrin

eye drops 2.5% dropper bottle 5 ml, № 1

Sentiss Pharma

dropper 5 ml, No. 1

Nextpharm GmbH

Prices in pharmacies

Mezaton

eye drops 25 mg/ml 5 ml bottle with dropper cap, No. 1

Zdorovye

Prices in pharmacies ax

Mezaton

solution for injection 10 mg/ml ampoule 1 ml blister pack, № 10 9No. 1 Prices in pharmacies

Nazol ^® Kids

nasal spray 0.25% bottle 10 ml with spray, No. 1

Bayer

Prices in pharmacies

Relief 9008 1 ®

ointment rectal tube 28.4 g with applicator, № 1

Bayer

Pharmacy prices

Relief ^®

rectal suppositories 5 mg strip, № 12

Bayer

Pharmacy prices

Fenephrine 10%

eye drops, solution 10 % dropper bottle 10 ml, No. 1

Unimed Pharma

Prices in pharmacies

Phenylephrine is a synthetic substitute for epinephrine, similar in pharmacological properties to this amine, differs from it in lower activity, but is more stable, retains activity when taken orally and has a strong and lasting effect in therapeutic doses.

collapse, shock, myocardial infarction, acute poisoning, infectious diseases, arterial hypotension, vasomotor rhinitis, allergic conjunctivitis, urticaria, glaucoma (together with cholinomimetics), iritis, iridocyclitis; as a substitute for epinephrine in combination with local anesthetics.

Rectal use: symptomatic treatment of itching, burning and discomfort that accompany hemorrhoids and other diseases of the anorectal zone, as well as erosion, cracks, microtrauma in the anus.

s.c., i.m. 0.3–1 ml 1% solution; in / in 0.1–0.3 ml of 1% solution; locally, 2–5 drops of 0.25–0.5% solution for the mucous membranes of the nasal cavity and mouth; in the eye, 2 drops of 1% solution; for local anesthesia add 0.3–0.5 ml of 1% solution per 10 ml of local anesthetic solution.

Higher doses: s / c and / m – single 0.01 g, daily 0.05 g; IV – single 0.005 g, daily 0.025 g.

Rectal ointment: applied to the affected areas outside or inside the anus up to 4 times a day, preferably in the evening, in the morning or after each bowel movement.

Rectal suppositories: 1 suppository up to 4 times a day, especially at night, in the morning and after each bowel movement. The duration of treatment is 7-14 days.

see epinephrine.

see epinephrine.

see epinephrine.

Phenylephrine: mechanism and time of action on the body

• Phenylephrine effectively improves nasal breathing (more than 9 times greater than placebo in increasing nasal airflow)

  ⁷

  Phenylephrine versus placebo airflow resistance curve

  Significant improvement in nasal breathing was observed 30 minutes after phenylephrine administration. ⁷

  In a single dose double-blind study of phenylephrine (tablets), 10, 15 and 25 mg, compared with placebo in 48 patients with cold-related nasal congestion. ⁷

  A statistically significantly lower nasal airflow resistance curve was obtained at 0-3 hours on day 1 after phenylephrine administration compared with placebo (p=0.006; primary endpoint), while subjective nasal airflow resistance was also statistically significant (p=0.001; secondary endpoint). On Day 3, after repeated dosing, the phenylephrine group had a statistically significantly lower nasal airflow resistance compared to placebo (p<0. 001). ⁷

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  The graph shows how effective phenylephrine is in clearing nasal congestion.

  In a meta-analysis of seven crossover studies and in a re-analysis of a parallel group study in 113 patients with acute nasal congestion due to the common cold. ⁸

  Phenylephrine 10 mg (1 capsule) was found to be significantly more effective (p < 0.05) than placebo in reducing nasal airway resistance 30 minutes after application. ⁸

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• When used systemically, phenylephrine prevents the recurrence of nasal congestion

  ⁹

  Phenylephrine reduces the risk of recurrence of nasal congestion compared with topical oral administration

  When used systemically, decongestants such as phenylephrine may have a slower onset of action and constriction of small vessels in the nasal cavity does not occur as abruptly as with topical drugs, so recurrence of nasal congestion is less likely. ¹⁰

• Phenylephrine – to relieve symptoms of colds and flu

  Phenylephrine can be used to relieve cold and flu symptoms

  Phenylephrine, in combination with other active ingredients such as paracetamol, ascorbic acid, pheniramine (chlorphenamine), can be used as a multi-symptom remedy for cold and flu symptoms. ^1–5

• Possible side effects

  Although phenylephrine is generally well tolerated, systemic absorption and interactions with other medicinal products may occur if absorbed into the systemic circulation. ¹¹

  Concomitant use of phenylephrine with other sympathomimetic agents may increase the risk of cardiovascular side effects such as increased blood pressure, tachycardia and palpitations. In patients treated with phenylephrine, the following adverse events were recorded with varying frequency: nervousness, headache, dizziness, insomnia, nausea and vomiting, as well as acute angle-closure glaucoma and immune system disorders such as allergic dermatitis, rash, mydriasis and dysuria or urinary retention.