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Acetaminophen / dextromethorphan / doxylamine / phenylephrine Side Effects

For the Consumer

Applies to acetaminophen / dextromethorphan / doxylamine / phenylephrine: liquid

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

Dizziness; drowsiness; dry mouth, nose, or throat; headache; nausea; nervousness; trouble sleeping.

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

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; dark urine; difficulty urinating or inability to urinate; fast or irregular heartbeat; hallucinations; mental or mood changes; pale stools; seizures; severe nervousness, drowsiness, or trouble sleeping; severe or persistent dizziness, lightheadedness, or headache; severe or persistent stomach pain, nausea, or vomiting; tremor; unusual fatigue; vision changes; yellowing of the skin or eyes.

For Healthcare Professionals

Applies to acetaminophen / dextromethorphan / doxylamine / phenylephrine: oral capsule, oral liquid, oral tablet, oral tablet effervescent


Cardiovascular side effects have included palpitations, arrhythmias, and cardiovascular collapse with hypotension.[Ref]


Dermatologic side effects associated with acetaminophen includes the risk of rare but potentially fatal serious skin reactions known as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP).


Gastrointestinal side effects have included nausea and vomiting.[Ref]


Genitourinary side effects have included dysuria.[Ref]


General side effects have included pallor and weakness.[Ref]


Hypersensitivity side effects have included rare reports of fixed-drug eruptions.[Ref]

Nervous system

Nervous system side effects have included marked drowsiness and excitability.[Ref]


Psychiatric side effects have included hallucinations, fear, and anxiety.[Ref]


1. "Product Information. Alka-Seltzer Plus Night-Time Cold (APAP/dextromethorphan/doxylamine/PE)." Bayer Pharmaceutical Inc, West Haven, CT.

Not all side effects for acetaminophen / dextromethorphan / doxylamine / 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.

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. 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.