dextromethorphan, guaifenesin, and phenylephrine

What is the most important information I should know about this medicine?

Do not use this medicine if you have taken an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

What is dextromethorphan, guaifenesin, and phenylephrine?

Dextromethorphan is a cough suppressant that affects signals in the brain that trigger cough reflex. Guaifenesin is an expectorant that loosens congestion in your chest and throat. Phenylephrine is a decongestant that shrinks blood vessels in the nasal passages.

Dextromethorphan, guaifenesin, and phenylephrine is a combination medicine used to treat cough, stuffy nose, and chest congestion caused by allergies, the common cold, or the flu.

There are many brands and forms of this medicine available. Not all brands are listed on this leaflet.

Dextromethorphan, guaifenesin, and phenylephrine may also be used for purposes not listed in this medication guide.

What should I discuss with my healthcare provider before taking this medicine?

Do not use this medicine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

Ask a doctor or pharmacist if this medicine is safe to use if you have:

• heart disease, high blood pressure;
• diabetes;
• a thyroid disorder;
• urination problems;
• glaucoma;
• epilepsy or other seizure disorder;
• pheochromocytoma (an adrenal gland tumor); or
• cough with mucus, or cough caused by emphysema or chronic bronchitis.

This medicine may contain phenylalanine. Check the medication label if you have phenylketonuria (PKU).

Ask a doctor before using this medicine if you are pregnant or breast-feeding.

How should I take this medicine?

Use exactly as directed on the label, or as prescribed by your doctor. Cold or cough medicine is only for short-term use until your symptoms clear up.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Drink extra fluids to help loosen the congestion and lubricate your throat while you are taking this medication.

If you need surgery or medical tests, tell the surgeon or doctor ahead of time if you have taken this medicine within the past few days.

What happens if I miss a dose?

Since cough or cold medicine is used when needed, you may not be on a dosing schedule. Skip any missed dose if it's almost time for your next dose. Do not use two doses at one time.

What happens if I overdose?

What should I avoid while taking this medicine?

Ask a doctor or pharmacist before using other cough or cold medicines that may contain similar ingredients.

What are the possible side effects of this medicine?

• little or no urination;
• fast or slow heartbeats;
• confusion, dizziness, feeling unsteady;
• nervousness, sleep problems (insomnia);
• severe nausea or vomiting;
• severe headache, blurred vision, pounding in your neck or ears;
• slow breathing; or
• unusual changes in mood or behavior.

Common side effects may include:

• diarrhea, constipation;
• dizziness, drowsiness;
• sleep problems (insomnia); or
• feeling nervous, restless, or irritable.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect dextromethorphan, guaifenesin, and phenylephrine?

Avoid using this medicine with other drugs that cause drowsiness or slow your breathing (such as opioid medicine, a muscle relaxer, or medicine for anxiety or seizures). Ask a doctor or pharmacist before using any other medication, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed in this medication guide.

Where can I get more information?

Your pharmacist can provide more information about dextromethorphan, guaifenesin, and phenylephrine.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. 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 drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2023 Cerner Multum, Inc. Version: 5.01. Revision date: 2/18/2022.