Skip to Content

Acetaminophen / dextromethorphan / diphenhydramine / phenylephrine Side Effects

Applies to acetaminophen / dextromethorphan / diphenhydramine / phenylephrine: packets

Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Anxiety; constipation; diarrhea; dizziness; drowsiness; dry mouth, nose, or throat; excitability; headache; nausea; trouble sleeping; upset stomach; vomiting; weakness.

Seek medical attention right away if any of these SEVERE side effects occur while taking acetaminophen / dextromethorphan / diphenhydramine / phenylephrine:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); fast or irregular heartbeat; fever, chills, or persistent sore throat; hallucinations; loss of coordination; mental or mood changes (eg, depression, nervousness); seizures; severe dryness of mouth, nose, and throat; severe or persistent dizziness, drowsiness, light-headedness, or headache; severe or persistent trouble sleeping; shortness of breath; symptoms of liver problems (eg, dark urine, loss of appetite, pale stools, stomach pain, yellowing of the skin or eyes); tremor; trouble urinating or inability to urinate; unusual bruising or bleeding; unusual tiredness or weakness; vision problems (eg, double vision, blurred vision).

Not all side effects for acetaminophen / dextromethorphan / diphenhydramine / phenylephrine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

More about acetaminophen/dextromethorphan/diphenhydramine/phenylephrine

Consumer resources

Related treatment guides

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

Hide