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Dextromethorphan HBr (cough suppressant)

Written by Stephanie Nera, RPh, PharmD · Pharmacology

Updated Jul 14, 2021

Dextromethorphan hydrobromide (HBr) is a generic drug that treats cough. It is a derivative of codeine that is available over the counter (OTC). There are various brands and preparations that contain dextromethorphan alone or in combination with other drugs.



What is dextromethorphan used for?

  • Suppressing cough due to colds
  • Throat irritation
  • Dry coughs
  • How should I take dextromethorphan?

    Read the directions on the packaging for complete information. Check the label and expiration date.

    For oral capsules or tablets, swallow it whole without chewing, crushing, or dissolving it in liquid.

    Lozenges should be placed in the mouth and dissolved slowly. Do not swallow it whole, chew, or dissolve it in water.

    Syrups and elixirs should be measured with a medical-grade measuring cup, not a household spoon.

    How do I store dextromethorphan?

    Store this product at controlled room temperature away from direct light and moisture. To prevent drug damage, you should not store it in the bathroom or the freezer. 

    There may be different brands of this drug that may have different storage needs. So, it is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

    You should not flush this product down the toilet or pour them into a drain unless instructed to do so. Additionally, it is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

    Precautions & Warnings

    What should I know before using dextromethorphan?

    Before using this drug, tell your doctor if you are/have:

    • Pregnant or breastfeeding.
    • Taking any other medicines. This includes any prescription, OTC, and herbal remedies.
    • An allergy to any of the ingredients of this product.
    • Any other illnesses, disorders, or medical conditions.

    Is it safe during pregnancy or breastfeeding?

    Unfortunately, there isn’t enough information about the safety of using this drug during pregnancy and breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking any medication.

    This medication is pregnancy risk category C according to the US Food and Drug Administration (FDA).

    FDA pregnancy risk category reference below:

    • A= No risk
    • B= No risk in some studies
    • C= There may be some risk
    • D= Positive evidence of risk
    • X= Contraindicated
    • N= Unknown

    Side Effects

    What side effects can occur from dextromethorphan?

    Like all drugs, this product may have side effects. If they occur, side effects are generally mild and resolve once treatment is finished or the dose is lowered. Some reported side effects include:

    • Abdominal pain
    • Diarrhea
    • Nausea
    • Vomiting
    • Dizziness
    • Drowsiness
    • Convulsion
    • Excitation
    • Nervousness or anxiety
    • Insomnia
    • Confusion
    • Respiratory depression
    • Serotonin syndrome

    However, not everyone experiences these side effects. In addition, some people may experience other side effects. So, if you have any concerns about a side effect, please consult your doctor or pharmacist.


    What drugs may interact with dextromethorphan?

    This medication may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. 

    To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. 

    Drugs with known interactions:

    • Antihistamines
    • Psychotropics
    • Other CNS depressants
    • Fluoxetine
    • Paroxetine
    • Quinidine
    • Terbinafine
    • MAOIs
    • SSRIs

    If you experience an adverse drug interaction, inform your doctor immediately to reevaluate your treatment plan. Approaches include dose adjustment, drug substitution, or ending therapy.

    Does food or alcohol interact with dextromethorphan?

    This drug may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Do not consume alcohol while taking this drug. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

    What health conditions may interact with  dextromethorphan?

    This drug may interact with underlying conditions. This interaction may worsen your health condition or alter the way the drug works. Therefore, it is important to always let your doctor and pharmacist know all the health conditions you currently have, such as:

    • Asthma
    • Emphysema
    • Liver disease
    • Smoking


    The information provided is not a substitute for any medical advice. Therefore, you should always consult with your doctor or pharmacist before using any medication.

    What is the dose for an adult?

    Take 5 to 10 mL every 4 hours, or as directed by your doctor. 

    What is the dose for a child?

    For children ages 6 to 12 years, give 2.5 to 5 mL every 4 hours, or as directed by a pediatrician. Do not give it to children under 6 years old.

    Children ages 12 and older: same as the adult dose.

    How is dextromethorphan available?

    Dextromethorphan is available in the following dosage forms and strengths: 

    • Capsule: 15 mg
    • Syrup: 10mg/5mL
    • Lozenge or cough drop: 5 mg

    What should I do in case of an emergency or overdose?

    In case of an emergency or an overdose, call your local emergency services or go to the nearest emergency room.

    What should I do if I miss a dose?

    If you miss a dose, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.


    Hello Health Group does not provide medical advice, diagnosis or treatment.

    Written by

    Stephanie Nera, RPh, PharmD


    Updated Jul 14, 2021

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