What are the primary uses of phenylephrine in medicine. How does phenylephrine work to relieve nasal congestion. What are the potential side effects of phenylephrine. Who should exercise caution when using phenylephrine-containing medications.

Understanding Phenylephrine: A Common Decongestant

Phenylephrine is a widely used decongestant found in many over-the-counter cold and allergy medications. It’s primarily employed to provide temporary relief from nasal congestion and associated symptoms. But how exactly does this medication work, and what should users be aware of?

How Does Phenylephrine Work?

Phenylephrine functions by constricting blood vessels in the nasal passages. This action reduces swelling and inflammation in the nose and sinuses, which in turn:

• Decreases nasal congestion
• Eases breathing difficulties
• Relieves pressure in the sinuses and ears

By targeting the root cause of congestion, phenylephrine offers quick and effective relief for many users. However, it’s important to note that while it alleviates symptoms, it does not cure the underlying condition causing the congestion.

Common Uses of Phenylephrine in Medicine

Phenylephrine is found in numerous over-the-counter medications and is used to treat a variety of conditions. What are the primary uses of this decongestant? Here’s a breakdown:

1. Relief from common cold symptoms
2. Alleviation of flu-related nasal congestion
3. Management of allergy symptoms
4. Temporary relief from sinusitis
5. Easing congestion associated with bronchitis

It’s crucial to understand that while phenylephrine can provide significant relief, it’s not a cure-all. For persistent or severe symptoms, consulting a healthcare professional is always recommended.

Proper Administration and Dosage Guidelines

Correct usage of phenylephrine is essential for both safety and efficacy. How should one properly take this medication? Let’s explore the guidelines:

• Always follow the instructions on the product packaging or as directed by a healthcare provider.
• Phenylephrine can be taken with or without food.
• For liquid formulations, use a proper measuring device to ensure accurate dosing.
• Chewable tablets should be thoroughly chewed before swallowing.
• Dissolvable tablets or strips should be placed on the tongue and allowed to dissolve completely.

Dosage is typically based on age, with different recommendations for adults and children. It’s crucial not to exceed the recommended dose or frequency of use without medical advice.

Can phenylephrine be used in children?

The use of phenylephrine in children requires careful consideration. Cough and cold products containing phenylephrine are not recommended for children under 6 years old unless specifically prescribed by a doctor. Some long-acting formulations are not suitable for children under 12. Always consult a pediatrician before administering phenylephrine to children.

Potential Side Effects and Risks

While phenylephrine is generally considered safe when used as directed, it can cause side effects in some individuals. What are the most common side effects associated with phenylephrine use?

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

In most cases, these side effects are mild and resolve on their own. However, if they persist or worsen, it’s important to consult a healthcare provider.

Are there any serious side effects to be aware of?

While rare, phenylephrine can occasionally cause more severe side effects. These may include:

• Irregular or rapid heartbeat
• Severe, uncontrolled shaking
• Difficulty urinating
• Seizures
• Significant changes in mood or behavior

If any of these serious side effects occur, immediate medical attention should be sought. Additionally, although rare, some individuals may experience an allergic reaction to phenylephrine, characterized by rash, itching, swelling, severe dizziness, or difficulty breathing. Such reactions require emergency medical care.

Precautions and Contraindications

Not everyone should use phenylephrine, and certain individuals need to exercise caution when considering its use. Who should be particularly careful about using phenylephrine-containing medications?

• Individuals with high blood pressure
• Those with heart conditions, including angina or irregular heartbeat
• People with diabetes
• Individuals with glaucoma
• Those with thyroid disorders
• People with a history of seizures
• Individuals with difficulty urinating due to an enlarged prostate

It’s crucial to inform your healthcare provider about all medical conditions and medications you’re taking before using phenylephrine. This includes both prescription and over-the-counter drugs, as well as herbal supplements.

Is phenylephrine safe during pregnancy and breastfeeding?

The safety of phenylephrine during pregnancy and breastfeeding is not fully established. Pregnant or nursing women should consult their healthcare provider before using any medication containing phenylephrine. In many cases, alternative treatments may be recommended.

Interactions with Other Medications

Phenylephrine can interact with various other medications, potentially altering their effectiveness or increasing the risk of side effects. What are some of the most significant drug interactions to be aware of?

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

It’s essential to provide a complete list of all medications and supplements you’re taking to your healthcare provider or pharmacist before using phenylephrine. This helps prevent potentially dangerous drug interactions.

Can phenylephrine be combined with other cold and flu medications?

Many over-the-counter cold and flu remedies contain multiple active ingredients, including phenylephrine. It’s crucial to read labels carefully to avoid accidentally doubling up on decongestants or other medications. When in doubt, consult a pharmacist or healthcare provider about the safety of combining different products.

Effectiveness and Limitations of Phenylephrine

While phenylephrine is widely used and can provide significant relief for many people, it’s important to understand its limitations. How effective is phenylephrine as a decongestant?

Research on the effectiveness of oral phenylephrine has yielded mixed results. Some studies suggest that it may not be significantly more effective than a placebo for nasal congestion when taken orally. However, many users report noticeable relief from symptoms.

It’s worth noting that phenylephrine does not:

• Cure the underlying condition causing congestion
• Shorten the duration of a cold or flu
• Prevent the spread of infectious illnesses

For optimal management of cold, flu, or allergy symptoms, phenylephrine may be most effective when used in combination with other treatments and self-care measures.

Are there alternatives to phenylephrine for nasal congestion?

Yes, there are several alternatives to phenylephrine for managing nasal congestion:

• Pseudoephedrine (available behind the pharmacy counter in many countries)
• Nasal sprays containing oxymetazoline or phenylephrine
• Nasal corticosteroid sprays
• Saline nasal irrigation
• Steam inhalation

Each of these options has its own benefits and potential drawbacks. Consulting with a healthcare provider can help determine the most appropriate treatment for individual circumstances.

Long-term Use and Potential for Abuse

Phenylephrine, like many decongestants, is intended for short-term use only. What are the risks associated with prolonged or excessive use of phenylephrine?

Extended use of phenylephrine can lead to:

• Rebound congestion, where symptoms worsen when the medication wears off
• Increased tolerance, requiring higher doses for the same effect
• Chronic nasal inflammation
• Potential for cardiovascular effects with long-term use

It’s generally recommended to limit the use of phenylephrine to no more than 7 consecutive days unless directed otherwise by a healthcare provider. If symptoms persist beyond this period, it’s important to seek medical advice, as there may be an underlying condition requiring different treatment.

Can phenylephrine be habit-forming?

While phenylephrine itself is not considered addictive in the traditional sense, users can develop a psychological dependence on its decongestant effects. This is particularly true for individuals with chronic nasal congestion who may rely on the medication for daily relief. It’s crucial to address the root cause of persistent congestion rather than relying on long-term decongestant use.

In rare cases, phenylephrine has been misused for its stimulant properties. However, this is uncommon and can be extremely dangerous, potentially leading to severe cardiovascular effects or other serious health complications.

Special Considerations for Specific Populations

Certain groups of people may need to take extra precautions when using phenylephrine. What are some special considerations for specific populations?

Elderly Users

Older adults may be more sensitive to the effects of phenylephrine, particularly its impact on blood pressure and heart rate. They may also be at increased risk of urinary retention, especially men with enlarged prostates. Careful monitoring and potentially lower doses may be necessary for this population.

Individuals with Cardiovascular Conditions

People with heart disease, high blood pressure, or a history of stroke should use phenylephrine with caution. The medication’s effects on blood vessels can potentially exacerbate these conditions. Close medical supervision is often required in such cases.

Diabetics

Phenylephrine can affect blood sugar levels in some individuals. Diabetics should monitor their glucose levels closely when using this medication and consult their healthcare provider if any significant changes occur.

Athletes

Some sporting organizations have restrictions on the use of decongestants, including phenylephrine. Athletes should check with their governing bodies before using phenylephrine, especially before competitions.

In all cases, it’s crucial to consult with a healthcare provider for personalized advice on the use of phenylephrine, particularly for individuals with pre-existing health conditions or those taking other 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]

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References

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Drugs and Lactation Database (LactMed®) [Internet]. National Institute of Child Health and Human Development; Bethesda (MD): Oct 31, 2018. Phenylephrine. [PubMed: 30000498]

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Cooper BE. Review and update on inotropes and vasopressors. AACN Adv Crit Care. 2008 Jan-Mar;19(1):5-13; quiz 14-5. [PubMed: 18418098]

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Mercier FJ, Augè M, Hoffmann C, Fischer C, Le Gouez A. Maternal hypotension during spinal anesthesia for caesarean delivery. Minerva Anestesiol. 2013 Jan;79(1):62-73. [PubMed: 23135692]

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Dellinger RP, Levy MM, Rhodes A, Annane D, Gerlach H, Opal SM, Sevransky JE, Sprung CL, Douglas IS, Jaeschke R, Osborn TM, Nunnally ME, Townsend SR, Reinhart K, Kleinpell RM, Angus DC, Deutschman CS, Machado FR, Rubenfeld GD, Webb S, Beale RJ, Vincent JL, Moreno R., Surviving Sepsis Campaign Guidelines Committee including The Pediatric Subgroup. Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock, 2012. Intensive Care Med. 2013 Feb;39(2):165-228. [PMC free article: PMC7095153] [PubMed: 23361625]

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Yue JK, Tsolinas RE, Burke JF, Deng H, Upadhyayula PS, Robinson CK, Lee YM, Chan AK, Winkler EA, Dhall SS. Vasopressor support in managing acute spinal cord injury: current knowledge. J Neurosurg Sci. 2019 Jun;63(3):308-317. [PubMed: 28252264]

6.

Yamazaki T, Shimada Y, Taenaka N, Oshumi H, Takezawa J, Yoshiya I. Circulatory responses to afterloading with phenylephrine in hyperdynamic sepsis. Crit Care Med. 1982 Jul;10(7):432-5. [PubMed: 7083867]

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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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Gregory JS, Bonfiglio MF, Dasta JF, Reilley TE, Townsend MC, Flancbaum L. Experience with phenylephrine as a component of the pharmacologic support of septic shock. Crit Care Med. 1991 Nov;19(11):1395-400. [PubMed: 1935160]

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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.