Skip to Content

NalDex Side Effects

Generic Name: dexchlorpheniramine / phenylephrine

Note: This page contains side effects data for the generic drug dexchlorpheniramine / phenylephrine. It is possible that some of the dosage forms included below may not apply to the brand name NalDex.

For the Consumer

Applies to dexchlorpheniramine / phenylephrine: tablets

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

Constipation; diarrhea; dizziness; drowsiness; dry mouth; excitability; headache; loss of appetite; nausea; nervousness or anxiety; trouble sleeping; upset stomach; vomiting; weakness.

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

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); blurred vision or other vision changes; difficulty urinating or inability to urinate; fast or irregular heartbeat; fever, chills, or persistent sore throat; hallucinations; mood or mental changes; persistent trouble sleeping; restlessness; seizures; severe dizziness, light-headedness, or headache; severe drowsiness; tremor.

For Healthcare Professionals

Applies to dexchlorpheniramine / phenylephrine: oral tablet, oral tablet extended release


Gastrointestinal side effects have included nausea, dry mouth, anorexia, and heartburn.[Ref]

Nervous system

Nervous system side effects have included headache, dizziness, mild sedation, tremor, weakness, insomnia, drowsiness, restlessness, convulsions, central nervous system depression, and nervousness.[Ref]


Genitourinary side effects have included dysuria.[Ref]


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


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


Respiratory side effects have included respiratory difficulty.[Ref]


Dermatologic side effects have included very rare reports of dermatitis.[Ref]


Ocular side effects have included blurring of vision.[Ref]


1. "Product Information. RhinaHist (dexchlorpheniramine-phenylephrine)." ProEthic Laboratories LLC, Montgomery, AL.

It is possible that some side effects of NalDex may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

More about NalDex (dexchlorpheniramine / phenylephrine)

Consumer resources

Other brands: RhinaHist

Professional 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. 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.