Phenylephrine 10mg/ml Inj, 1ml
It is used to treat low blood pressure.
Drug Class
Vasopressor
Pharmacologic Class
Alpha-1 Adrenergic Agonist
Pregnancy Category
Category C
FDA Approved
Jan 1939
DEA Schedule
Not Controlled
Overview
What is this medicine?
Phenylephrine injection is a medicine given by injection, usually in a hospital setting. It works by tightening blood vessels to raise blood pressure, which is important when blood pressure drops too low, for example, during surgery or certain medical conditions. It can also be used to treat a fast heart rhythm called PSVT.
How to Use This Medicine
To use this medication correctly, follow your doctor's instructions and carefully read all the information provided. Take this medication exactly as directed, and follow all instructions closely. This medication is administered via injection into a vein, either as a single dose or continuously over a period of time.
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist for guidance on proper storage procedures.
In the event that you miss a dose, contact your doctor promptly to determine the best course of action.
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist for guidance on proper storage procedures.
In the event that you miss a dose, contact your doctor promptly to determine the best course of action.
Lifestyle & Tips
- This medication is administered in a controlled medical environment; no specific lifestyle modifications are required by the patient during administration.
- Patients should report any discomfort or unusual symptoms immediately to their healthcare provider.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
Hypotension (bolus): 0.1-0.5 mg (100-500 mcg) IV, may repeat every 10-15 minutes as needed. Hypotension (infusion): Initial 100-180 mcg/min IV, then maintenance 40-60 mcg/min IV. Titrate to desired blood pressure. Paroxysmal Supraventricular Tachycardia (PSVT): 0.5 mg IV rapid bolus.
Dose Range:
0.04 - 0.18 mg
Condition-Specific Dosing:
hypotension_bolus:
0.1-0.5 mg IV, repeat as needed
hypotension_infusion_initial:
100-180 mcg/min IV
hypotension_infusion_maintenance:
40-60 mcg/min IV
psvt:
0.5 mg IV rapid bolus
Pediatric Dosing
Neonatal:
Not established for routine use; in critical care, 0.5-5 mcg/kg/min IV infusion, titrate to effect.
Infant:
Not established for routine use; in critical care, 0.5-5 mcg/kg/min IV infusion, titrate to effect.
Child:
Not established for routine use; in critical care, 0.5-5 mcg/kg/min IV infusion, titrate to effect.
Adolescent:
Adult dosing may apply, but caution and titration to effect are paramount.
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment recommended, titrate to effect.
Moderate:
No specific dose adjustment recommended, titrate to effect.
Severe:
No specific dose adjustment recommended, titrate to effect; monitor closely for exaggerated response.
Dialysis:
Not available; titrate to effect, as phenylephrine is primarily metabolized, not dialyzed.
Hepatic Impairment:
Mild:
No specific dose adjustment recommended, titrate to effect.
Moderate:
No specific dose adjustment recommended, titrate to effect; monitor closely.
Severe:
No specific dose adjustment recommended, titrate to effect; monitor closely for exaggerated response due to impaired metabolism.
Pharmacology
Mechanism of Action
Phenylephrine is a direct-acting sympathomimetic amine that acts almost exclusively on alpha-1 adrenergic receptors, causing potent vasoconstriction in arterioles and venules. This leads to an increase in peripheral vascular resistance, systemic arterial pressure, and often, a reflex bradycardia. It has minimal beta-adrenergic stimulating effects.
Pharmacokinetics
Absorption:
Bioavailability:
100% (IV)
Tmax:
Immediate (IV)
FoodEffect:
Not applicable (IV administration)
Distribution:
Vd:
Not readily available (highly variable)
ProteinBinding:
Not extensively protein bound
CnssPenetration:
Limited
Elimination:
HalfLife:
Approximately 2.5 hours (IV)
Clearance:
Not readily available (highly variable)
ExcretionRoute:
Renal (as metabolites and unchanged drug)
Unchanged:
<16% (IV)
Pharmacodynamics
OnsetOfAction:
Immediate (IV)
PeakEffect:
1-2 minutes (IV bolus)
DurationOfAction:
15-20 minutes (IV bolus)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high blood pressure, including:
+ Severe headache
+ Dizziness
+ Passing out
+ Changes in eyesight
Chest pain or pressure
Shakiness
Signs of kidney problems, such as:
+ Inability to pass urine
+ Changes in urine output
+ Blood in the urine
+ Sudden weight gain
Abnormal heartbeat (fast, slow, or irregular)
Blurred vision
Shortness of breath
Sudden weight gain
Swelling in the arms or legs
Numbness or tingling in the hands or feet
If you experience any of these symptoms, it is crucial to seek medical help immediately.
Additional Side Effects:
Most people taking this medication do not experience severe side effects. However, some may encounter mild or moderate side effects. If you experience any of the following symptoms, contact your doctor if they bother you or do not resolve on their own:
Dizziness
Headache
Feeling nervous or excitable
Trouble sleeping
Restlessness
Upset stomach or vomiting
Excessive sweating
Stomach pain
Neck pain
Reporting Side Effects:
If you have questions or concerns about side effects, contact your doctor for medical advice. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Important Note:
If you receive this medication through a vein, it is essential to monitor the injection site for signs of tissue damage, such as redness, burning, pain, swelling, blisters, skin sores, or fluid leakage. Inform your nurse immediately if you notice any of these symptoms.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high blood pressure, including:
+ Severe headache
+ Dizziness
+ Passing out
+ Changes in eyesight
Chest pain or pressure
Shakiness
Signs of kidney problems, such as:
+ Inability to pass urine
+ Changes in urine output
+ Blood in the urine
+ Sudden weight gain
Abnormal heartbeat (fast, slow, or irregular)
Blurred vision
Shortness of breath
Sudden weight gain
Swelling in the arms or legs
Numbness or tingling in the hands or feet
If you experience any of these symptoms, it is crucial to seek medical help immediately.
Additional Side Effects:
Most people taking this medication do not experience severe side effects. However, some may encounter mild or moderate side effects. If you experience any of the following symptoms, contact your doctor if they bother you or do not resolve on their own:
Dizziness
Headache
Feeling nervous or excitable
Trouble sleeping
Restlessness
Upset stomach or vomiting
Excessive sweating
Stomach pain
Neck pain
Reporting Side Effects:
If you have questions or concerns about side effects, contact your doctor for medical advice. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Important Note:
If you receive this medication through a vein, it is essential to monitor the injection site for signs of tissue damage, such as redness, burning, pain, swelling, blisters, skin sores, or fluid leakage. Inform your nurse immediately if you notice any of these symptoms.
Seek Immediate Medical Attention If You Experience:
- Severe headache
- Chest pain or tightness
- Irregular heartbeat or palpitations
- Difficulty breathing
- Dizziness or lightheadedness
- Numbness or tingling in extremities
- Pain, swelling, or discoloration at the injection site
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced.
If you have high blood pressure, as this medication may affect your condition.
If you have taken certain medications for depression or Parkinson's disease within the last 14 days, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline. Combining these medications can lead to severely high blood pressure.
If you are currently taking linezolid or methylene blue, as these medications can interact with this drug.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine if it is safe to take this medication with your existing medications and health conditions. Never start, stop, or change the dose of any medication without consulting your doctor first.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced.
If you have high blood pressure, as this medication may affect your condition.
If you have taken certain medications for depression or Parkinson's disease within the last 14 days, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline. Combining these medications can lead to severely high blood pressure.
If you are currently taking linezolid or methylene blue, as these medications can interact with this drug.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine if it is safe to take this medication with your existing medications and health conditions. Never start, stop, or change the dose of any medication without consulting your doctor first.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you have a known allergy to sulfites, consult with your doctor, as some formulations of this drug may contain sulfites. Regular blood tests will be necessary, as directed by your doctor, to monitor your condition; be sure to discuss any concerns or questions with your doctor. Additionally, if you are pregnant, planning to become pregnant, or are breastfeeding, it is crucial to discuss the potential benefits and risks of this medication with your doctor to ensure the best possible outcome for both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe hypertension (dangerously high blood pressure)
- Reflex bradycardia (very slow heart rate)
- Ventricular arrhythmias
- Cerebral hemorrhage
- Pulmonary edema
- Cardiac arrest
What to Do:
Treatment is symptomatic and supportive. For severe hypertension, an alpha-adrenergic blocking agent (e.g., phentolamine) may be administered. Bradycardia may be treated with atropine. Call 911 or emergency services immediately.
Drug Interactions
Contraindicated Interactions
- Monoamine Oxidase Inhibitors (MAOIs) (e.g., phenelzine, selegiline, tranylcypromine, linezolid, methylene blue): Risk of severe, prolonged hypertension and hypertensive crisis.
Major Interactions
- Tricyclic Antidepressants (TCAs) (e.g., amitriptyline, imipramine): Potentiation of pressor effect, leading to severe hypertension.
- Oxytocic drugs (e.g., oxytocin, methylergonovine): Risk of severe persistent hypertension and stroke.
- Ergot alkaloids (e.g., ergotamine): Increased vasoconstrictor effects.
- Beta-blockers (non-selective): May result in unopposed alpha-adrenergic stimulation, leading to severe hypertension and reflex bradycardia.
- Other vasopressors (e.g., norepinephrine, epinephrine, dopamine): Additive pressor effects, increased risk of arrhythmias and hypertension.
Moderate Interactions
- Atropine: May potentiate the pressor response to phenylephrine.
- Cardiac glycosides (e.g., digoxin): Increased risk of arrhythmias.
- Inhalation anesthetics (e.g., halothane, isoflurane): May sensitize the myocardium to the effects of sympathomimetics, increasing risk of arrhythmias.
- Alpha-adrenergic blockers (e.g., phentolamine): May antagonize the pressor effect of phenylephrine.
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Blood Pressure (BP)
Rationale: To establish baseline hemodynamic status before initiating vasopressor therapy.
Timing: Prior to administration
Heart Rate (HR)
Rationale: To establish baseline and monitor for reflex bradycardia.
Timing: Prior to administration
Electrocardiogram (ECG)
Rationale: To assess for pre-existing arrhythmias or conduction abnormalities.
Timing: Prior to administration, especially in patients with cardiac history
Routine Monitoring
Blood Pressure (BP)
Frequency: Continuously (arterial line preferred) or every 1-5 minutes during titration, then every 5-15 minutes once stable.
Target: Individualized, typically Mean Arterial Pressure (MAP) >65 mmHg or Systolic BP >90 mmHg.
Action Threshold: BP outside target range; titrate infusion rate or administer bolus.
Heart Rate (HR)
Frequency: Continuously
Target: Individualized, typically 60-100 bpm, but monitor for significant bradycardia.
Action Threshold: Significant bradycardia (<50 bpm) or tachycardia (>120 bpm); assess for underlying cause, consider dose adjustment or atropine for severe bradycardia.
Cardiac Rhythm (ECG)
Frequency: Continuously
Target: Normal sinus rhythm, absence of significant arrhythmias.
Action Threshold: Development of new arrhythmias (e.g., PVCs, VT, bradyarrhythmias); assess for underlying cause, consider dose adjustment.
Urine Output
Frequency: Hourly
Target: >0.5 mL/kg/hr
Action Threshold: Oliguria (<0.5 mL/kg/hr); assess for hypoperfusion or renal injury.
Peripheral Perfusion (skin color, temperature, capillary refill)
Frequency: Every 1-4 hours
Target: Warm, dry, good capillary refill (<2 seconds)
Action Threshold: Cool, mottled extremities, prolonged capillary refill; indicates excessive vasoconstriction or hypoperfusion.
Injection Site
Frequency: Regularly (e.g., every 1-2 hours)
Target: No signs of extravasation
Action Threshold: Swelling, pain, blanching, or discoloration at injection site; stop infusion immediately, consider phentolamine for extravasation.
Symptom Monitoring
- Headache
- Palpitations
- Anxiety
- Tremor
- Dizziness
- Nausea/Vomiting
- Chest pain
- Shortness of breath
- Signs of extravasation (pain, swelling, blanching at IV site)
Special Patient Groups
Pregnancy
Category C. Use only if the potential benefit justifies the potential risk to the fetus. Phenylephrine can cause uterine vasoconstriction and reduce uterine blood flow, potentially leading to fetal hypoxia and bradycardia. Close monitoring of maternal and fetal status is essential if used.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm, but data are limited. Avoid if possible.
Second Trimester:
Risk of reduced uterine blood flow and fetal hypoxia.
Third Trimester:
Risk of reduced uterine blood flow, fetal hypoxia, and potential for premature labor due to uterine stimulation.
Lactation
L3 (Moderately safe). Limited data suggest that phenylephrine is poorly absorbed orally, so infant exposure via breast milk is likely low. However, caution is advised. Monitor the infant for signs of agitation, irritability, or changes in feeding/sleep patterns.
Infant Risk:
Low to moderate risk; monitor for irritability, changes in sleep patterns, or feeding difficulties.
Pediatric Use
Dosing is not well-established for all pediatric age groups and indications. Use in pediatric patients, especially neonates and infants, requires careful titration and close monitoring, typically in a critical care setting. Dosing is often weight-based (e.g., mcg/kg/min infusion).
Geriatric Use
Elderly patients may be more sensitive to the effects of phenylephrine, particularly regarding hypertension and reflex bradycardia. Start with lower doses and titrate slowly, monitoring blood pressure and heart rate closely. Increased risk of adverse cardiovascular events.
Clinical Information
Clinical Pearls
- Phenylephrine is a pure alpha-1 agonist, making it useful when increased systemic vascular resistance is desired without significant chronotropic or inotropic effects (unlike norepinephrine or epinephrine).
- Reflex bradycardia is a common and expected side effect due to the increase in blood pressure; this is often managed by the body's compensatory mechanisms but can be severe.
- Extravasation can cause severe tissue necrosis. Administer via a central venous line if possible. If extravasation occurs, infiltrate the area with phentolamine (alpha-blocker) to counteract vasoconstriction.
- Avoid use in patients with severe coronary artery disease, severe hypertension, or ventricular tachycardia due to increased myocardial oxygen demand and risk of arrhythmias.
- Careful titration is crucial; continuous arterial blood pressure monitoring is recommended during infusion.
Alternative Therapies
- Norepinephrine (Levophed): Mixed alpha and beta agonist, stronger inotropic/chronotropic effects.
- Epinephrine (Adrenalin): Mixed alpha and beta agonist, potent vasopressor and inotrope.
- Dopamine: Dose-dependent effects (dopaminergic, beta, alpha).
- Vasopressin (Pitressin): Non-adrenergic vasopressor, acts on V1 receptors.
- Ephedrine: Mixed direct and indirect sympathomimetic, less potent than phenylephrine.
Cost & Coverage
Average Cost:
Varies widely, typically low cost for generic injection per 1ml vial
Generic Available:
Yes
Insurance Coverage:
Typically covered by most insurance plans in hospital/clinic settings as it is an essential acute care medication.
General Drug Facts
If your symptoms or health problems persist or worsen, it is essential to contact your doctor promptly. To ensure safe use, never share your medication with others, and do not take medication prescribed for someone else. Store all medications in a secure location, out of reach of children and pets, to prevent accidental ingestion. Dispose of unused or expired medications properly. Unless instructed to do so by a healthcare professional, do not flush medications down the toilet or pour them down the drain. If you are unsure about the proper disposal method, consult your pharmacist for guidance. Many communities have drug take-back programs, which your pharmacist can help you locate. Some medications may come with an additional patient information leaflet; check with your pharmacist to see if this applies to your prescription. If you have any questions or concerns about your medication, discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. Be prepared to provide information about the medication taken, the amount, and the time it was taken, as this will aid in providing appropriate care.