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Phenylephrine / promethazine Side Effects

Medically reviewed by Last updated on Jun 29, 2022.

Applies to phenylephrine / promethazine: oral solution, oral syrup.


  • Do not give this drug to a child younger than 2 years of age. It may cause very bad and sometimes deadly breathing problems.
  • Use with care in children 2 years of age and older. Talk with the doctor.
  • Before your child takes this drug, tell the doctor if your child is taking any drugs that can cause breathing problems. There are many drugs that can do this. Ask the doctor or pharmacist if you are not sure.

Serious side effects

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like 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; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of high or low blood pressure like very bad headache or dizziness, passing out, or change in eyesight.
  • Fast or slow heartbeat.
  • Trouble passing urine.
  • Feeling very tired or weak.
  • Hallucinations (seeing or hearing things that are not there).
  • Mood changes.
  • Ringing in ears.
  • Seizures.
  • Any unexplained bruising or bleeding.
  • Trouble controlling body movements, twitching, change in balance, trouble swallowing or speaking.
  • Change in eyesight.
  • Yellow skin or eyes.
  • A very bad and sometimes deadly health problem called neuroleptic malignant syndrome (NMS) may happen. Call your doctor right away if you have any fever, muscle cramps or stiffness, dizziness, very bad headache, confusion, change in thinking, fast heartbeat, heartbeat that does not feel normal, or are sweating a lot.
  • This drug may cause very bad and sometimes deadly breathing problems. Call your doctor right away if you have slow, shallow, or trouble breathing.
  • Low white blood cell counts have rarely happened with this drug. This may lead to a higher chance of getting an infection. Tell your doctor if you have ever had a low white blood cell count. Call your doctor right away if you have signs of infection like fever, chills, or sore throat.

Other side effects

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Feeling sleepy.
  • Dizziness.
  • Feeling tired or weak.
  • Feeling nervous and excitable.
  • Dry mouth.
  • Upset stomach or throwing up.
  • Not able to sleep.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

For Healthcare Professionals

Applies to phenylephrine/promethazine: oral syrup.


One of the most commonly reported adverse reactions has included drowsiness.[Ref]

Nervous system


Frequency not reported: Sedation, sleepiness, somnolence, dizziness, tremor, weakness, and extrapyramidal symptoms such as oculogyric crisis, torticollis, and tongue protrusion, incoordination, seizures, neuroleptic malignant syndrome


Frequency not reported: Dizziness, tremor, weakness[Ref]



Frequency not reported: Euphoria, confusion, disorientation, restlessness, anxiety, nervousness, excitation, catatonic-like states, hysteria, hallucinations, nightmares, insomnia, delirium, agitated behavior


Frequency not reported: Restlessness, anxiety, nervousness



Frequency not reported: Increased or decreased blood pressure, tachycardia, bradycardia, faintness


Frequency not reported: Hypertension[Ref]



Frequency not reported: Blurred vision, diplopia[Ref]



Frequency not reported: Dry mouth, nausea, vomiting[Ref]



Frequency not reported: Leukopenia, thrombocytopenia, thrombocytopenic purpura, agranulocytosis[Ref]



Frequency not reported: Dermatitis, photosensitivity, urticaria, angioneurotic edema[Ref]



Frequency not reported: Respiratory distress, asthma, nasal stuffiness, apnea


Frequency not reported: Respiratory distress[Ref]



Frequency not reported: Jaundice



Frequency not reported: Lassitude, tinnitus, fatigue


Frequency not reported: Precordial pain


1. "Product Information. Promethazine VC (phenylephrine-promethazine)." Actavis U.S. (Alpharma USPD) (2017):

2. "Product Information. Phenergan VC (phenylephrine-promethazine)." Wyeth-Ayerst Laboratories (2002):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.