Phenylephrine / Promethazine Side Effects

Medically reviewed by Drugs.com. Last updated on Oct 19, 2023.

Applies to phenylephrine / promethazine: oral syrup.

Get emergency medical help if you have any of these signs of an allergic reaction while taking phenylephrine/promethazine: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using this medicine and call your doctor at once if you have:

• seizure (convulsions);

• weak or shallow breathing;

• jaundice (yellowing of the skin or eyes);

• confusion, hallucinations;

• sudden weakness or ill feeling, fever, chills, sore throat, mouth sores, red or swollen gums, trouble swallowing;

• uncontrollable movements of your eyes, lips, tongue, face, arms, or legs; or

• severe nervous system reaction--very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.

Common side effects may include:

• dizziness, drowsiness;

• dry mouth, nose, or throat;

• blurred vision; or

• constipation.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For healthcare professionals

Applies to phenylephrine / promethazine: oral syrup.

General adverse events

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

Nervous system

Promethazine:

• 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

Phenylephrine:

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

Psychiatric

Promethazine:

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

Phenylephrine:

• Frequency not reported: Restlessness, anxiety, nervousness

Cardiovascular

Promethazine:

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

Phenylephrine:

• Frequency not reported: Hypertension^[Ref]

Ocular

Promethazine:

• Frequency not reported: Blurred vision, diplopia^[Ref]

Gastrointestinal

Promethazine:

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

Hematologic

Promethazine:

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

Dermatologic

Promethazine:

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

Respiratory

Promethazine:

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

Phenylephrine:

• Frequency not reported: Respiratory distress^[Ref]

Hepatic

Promethazine:

• Frequency not reported: Jaundice

Other

Promethazine:

• Frequency not reported: Lassitude, tinnitus, fatigue

Phenylephrine:

• Frequency not reported: Precordial pain

See also:

Further information

Phenylephrine/promethazine 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