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phenylephrine (Intravenous route)



Commonly used brand name(s)

In the U.S.

  • Vazculep

Available Dosage Forms:

  • Solution

Therapeutic Class: Vasopressor

Pharmacologic Class: Sympathomimetic

Chemical Class: Alkylarylamine

Uses For phenylephrine

Phenylephrine injection is used to treat hypotension (low blood pressure) that may occur during surgery.

phenylephrine is to be given only by or under the direct supervision of your doctor.

Before Using phenylephrine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For phenylephrine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to phenylephrine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies have not been performed on the relationship of age to the effects of phenylephrine injection in the pediatric population. Safety and efficacy have not been established.


Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of phenylephrine injection in the elderly. However, elderly patients are more likely to have kidney, liver, or heart problems, which may require caution and an adjustment in the dose for patients receiving phenylephrine injection.


Pregnancy Category Explanation
All Trimesters C Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving phenylephrine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using phenylephrine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Linezolid
  • Rasagiline
  • Selegiline

Using phenylephrine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Amitriptyline
  • Amoxapine
  • Clomipramine
  • Desipramine
  • Dothiepin
  • Doxepin
  • Imipramine
  • Iobenguane I 123
  • Lofepramine
  • Nortriptyline
  • Opipramol
  • Protriptyline
  • Trimipramine

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of phenylephrine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Allergy to sulfites or
  • Asthma—phenylephrine contains sodium metabisulfite, which can make these conditions worse.
  • Angina, or history of or
  • Bradycardia (slow heartbeat) or
  • Blood vessel problems (eg, arteriosclerosis), severe or
  • Heart failure or
  • Peripheral vascular disease or
  • Pulmonary arterial hypertension or
  • Spinal cord injury—Use with caution. May make these conditions worse.
  • Kidney disease, severe or
  • Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

Proper Use of phenylephrine

A nurse or other trained health professional will give you phenylephrine in a hospital. phenylephrine is given through a needle placed in one of your veins.

Precautions While Using phenylephrine

Your doctor will check your progress closely while you are receiving phenylephrine. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to receive it. Blood tests may be needed to check for unwanted effects.

phenylephrine may cause a permanent depression (necrosis) under the skin at the injection site. Tell your doctor right away if you notice any of these side effects at the injection site: depressed or indented skin, blue-green to black skin discoloration, or pain, redness, or sloughing (peeling) of the skin.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

phenylephrine Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

Incidence not known
  • Blurred vision
  • chest pain or discomfort
  • difficult or labored breathing
  • dizziness
  • fainting
  • fast, slow, or irregular heartbeat
  • headache
  • nausea or vomiting
  • nervousness
  • pain in the shoulders, arms, jaw, or neck
  • pounding in the ears
  • sweating
  • tightness in the chest
  • unusual tiredness

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose
  • Feeling of fullness in the head
  • pounding or rapid pulse
  • tingling in the arms or legs
  • vomiting

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known
  • Heartburn
  • itching skin
  • nausea
  • pain in the neck
  • pain or discomfort in chest, upper stomach, or throat

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

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