Guaifenesin/dextromethorphan/decongestant - oral
phenylephrine-DM-guaifenesin 10 mg-15 mg-300 mg/5 mL oral liquid
This combination medication is used to temporarily treat cough, chest congestion, and stuffy nose symptoms caused by the common cold, flu, allergies, hay fever, or other breathing illnesses (such as sinusitis, bronchitis). Guaifenesin is an expectorant that helps to thin and loosen mucus in the lungs, making it easier to cough up the mucus. Dextromethorphan is a cough suppressant that affects a certain part of the brain (cough center), reducing the urge to cough. This product also contains a decongestant, which helps relieve stuffy nose symptoms.
This medication is usually not used for ongoing coughs from smoking, asthma, other long-term breathing problems (such as emphysema), or coughs with a lot of mucus, unless directed by your doctor.
Cough-and-cold products have not been shown to be safe or effective in children younger than 6 years. Do not use this product to treat cold symptoms in children younger than 6 years unless specifically directed by the doctor. Some products (such as long-acting tablets/capsules) are not recommended for use in children younger than 12 years. Ask your doctor or pharmacist for more details about using your product safely.
These products do not cure or shorten the length of the common cold and may cause serious side effects. To decrease the risk for serious side effects, carefully follow all dosage directions. Do not use this product to make a child sleepy. Do not give other cough-and-cold medication that might contain the same or similar ingredients (see also Drug Interactions section). Ask the doctor or pharmacist about other ways to relieve cough and cold symptoms (such as drinking enough fluids, using a humidifier or saline nose drops/spray).
If you are taking the over-the-counter product, read all directions on the product package before taking this medication. If you have any questions, consult your pharmacist. If your doctor has prescribed this medication, take it as directed.
Take the tablet, capsule, or liquid form by mouth with or without food. Follow the directions for dosing on the label, or take as directed by your doctor. Drink plenty of fluids when you use this medication unless otherwise directed by your doctor. The fluid will help loosen the mucus in your lungs. This medication can be taken with food if stomach upset occurs.
If you are using the liquid form, use a medication measuring device to carefully measure the prescribed dose. Do not use a household spoon. If your liquid form is a suspension, shake the bottle well before each dose.
If you are using sustained-release tablets or capsules, swallow the medication whole. Do not crush or chew the tablets or capsules. Doing so can destroy the long action of the drug and may increase side effects.
The dosage is based on your age, medical condition, and response to therapy.
Improper use of this medication (abuse) may result in serious harm (such as brain damage, seizure, death). Do not increase your dose or take this medication more often than recommended by your doctor or the package instructions without your doctor's approval.
Inform your doctor if your condition lasts for more than 1 week, if it gets worse, or if it occurs with a headache that doesn't go away, a fever, or a rash. These may be symptoms of a serious medical problem and should be checked by a doctor.
Dizziness, headache, nausea, nervousness, or trouble sleeping may occur. If any of these effects last or get worse, contact your doctor or pharmacist promptly.
If your doctor has prescribed this medication, remember that your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including:
- mental/mood changes (such as confusion, hallucinations)
- shaking (tremors)
- fast/slow/irregular heartbeat
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:
- itching/swelling (especially of the face/tongue/throat)
- severe dizziness
- trouble breathing
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before taking this medication, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of:
- breathing problems (such as asthma, emphysema)
- a certain eye problem (glaucoma)
- heart problems
- high blood pressure
- kidney problems
- overactive thyroid (hyperthyroidism)
- trouble urinating (for example, due to enlarged prostate)
This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).
Liquid preparations of this product may contain sugar, aspartame, and/or alcohol. Caution is advised if you have diabetes, alcohol dependence, liver disease, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using this product safely.
Older adults may be more sensitive to the side effects of this drug, especially dizziness, difficulty urinating, fast/irregular heartbeat, trouble sleeping, confusion, or mental/mood changes.
During pregnancy, this medication should be used only if clearly needed. Discuss the risks and benefits with your doctor.
This medication may pass into breast milk. Consult your doctor before breast-feeding.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Taking certain MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Avoid taking isocarboxazid, metaxalone, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, or tranylcypromine during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before treatment with this medication. Ask your doctor when to start or stop taking this medication.
Some products that may interact with this drug are:
- beta blockers (such as metoprolol, atenolol)
- certain inhaled anesthetics (such as halothane)
- tricyclic antidepressants (such as amitriptyline, desipramine)
Guaifenesin is available in both prescription and nonprescription products. Check the labels on all your medications carefully to make sure you are not taking more than one guaifenesin-containing product.
Check the labels on all your medicines (such as cough-and-cold products, diet aids) because they may contain ingredients that could increase your heart rate or blood pressure. Ask your pharmacist about the safe use of those products.
This medication may interfere with certain medical/lab tests (including urine 5-HIAA/VMA levels, brain scan for Parkinson's disease), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: agitation, confusion, hallucinations, seizures.
If your doctor has prescribed this medication, do not share it with others.
Keep all medical and lab appointments.
If you are prescribed this medication on a regular schedule and miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
Store at room temperature away from light and moisture. Do not store in the bathroom. Do not freeze liquid forms of this medication. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Information last revised January 2023.
Copyright(c) 2023 First Databank, Inc.
Selected from NATIONAL DRUG DATA FILE (NDDF) data included with permission and copyrighted by First Databank, Inc., 2019. This copyrighted material has been downloaded from a licensed data provider.
The above information is intended to supplement, not substitute for, the expertise and judgment of your health care professional. You should consult your health care professional before taking any drug, changing your diet, or commencing or discontinuing any course of treatment.