Neo-Synephrine Side Effects

Generic name: phenylephrine

Medically reviewed by Drugs.com. Last updated on Jan 24, 2025.

Note: This document provides detailed information about Neo-Synephrine Side Effects associated with phenylephrine. Some dosage forms listed on this page may not apply specifically to the brand name Neo-Synephrine.

Applies to phenylephrine: intravenous solution.

Serious side effects of Neo-Synephrine

Along with its needed effects, phenylephrine (the active ingredient contained in Neo-Synephrine) 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 while taking phenylephrine:

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 while taking phenylephrine:

Symptoms of overdose

• feeling of fullness in the head
• pounding or rapid pulse
• tingling in the arms or legs
• vomiting

Other side effects of Neo-Synephrine

Some side effects of phenylephrine 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

For healthcare professionals

Applies to phenylephrine: compounding powder, injectable solution, intravenous solution, oral disintegrating strip, oral liquid, oral suspension extended release, oral tablet, oral tablet chewable, oral tablet chewable extended release, oral tablet disintegrating.

Cardiovascular adverse events

• Frequency not reported: Bradycardia, AV block, ventricular extrasystoles, myocardial ischemia, hypertensive crisis^[Ref]

Nervous system

• Frequency not reported: Headache, paresthesia, tremor^[Ref]

Respiratory

• Frequency not reported: Pulmonary edema, rales^[Ref]

Psychiatric

• Frequency not reported: Nervousness, excitability^[Ref]

Gastrointestinal

• Frequency not reported: Nausea, vomiting^[Ref]

Local

• Frequency not reported: Extravasation^[Ref]

Hypersensitivity

• Frequency not reported: Sulfite sensitivity^[Ref]

Other

• Frequency not reported: Chest pain^[Ref]

Dermatologic

• Frequency not reported: Diaphoresis, pallor, piloerection, skin blanching, skin necrosis with extravasation^[Ref]

Frequently asked questions

• Phenylephrine vs Pseudoephedrine - How do they compare?
• Does Mucinex help with Covid?

Further information

Neo-Synephrine side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer