Cough Tablets for Dogs (Dextromethorphan and Guaifenesin)
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PetMD’s medications content was written and reviewed by veterinary professionals to answer your most common questions about how medications function, their side effects, and what species they are prescribed for. This content shouldn’t take the place of advice by your vet.
What Are Cough Tablets Used for in Dogs?
Cough Tablets for dogs (active ingredients dextromethorphan and guaifenesin) is a combination veterinary medication used to temporarily relieve the symptoms of coughing in dogs.
Veterinarians commonly prescribe Cough Tablets for dogs with canine infectious respiratory disease (CIRD), referred to as kennel cough—a collective term for a group of upper respiratory infections caused by several different viruses and bacteria. Often, a dog may be infected with one or more viruses or bacteria at the same time.
Cough Tablets are available for dogs 3 months of age or older who weigh at least 5 pounds.
Cough Tablets are generally only given short term for coughing symptoms caused by an upper respiratory infection and not used long term for coughing caused by other medical conditions.
Cough Tablet effects are short-lived because they will stop working within 24 hours.
Cough Tablets should be used with caution in dogs with chronic cough or dogs with decreased liver function because the effects may last longer under these circumstances.
Discuss your dog’s medications, including vitamins, supplements, herbal therapies, and flea and tick collars, and medical conditions with your veterinarian before giving your dog this medication.
Are Cough Tablets FDA-Approved?
The combination of active ingredients dextromethorphan/guaifenesin is FDA-approved for human use under the brand names Mucinex DM and Robitussin DM.
Cough Tablets for dogs, on the other hand, is currently not FDA-approved for use in dogs. It is, however, readily utilized in the veterinary field, and veterinarians can legally prescribe certain human drugs for use in animals in certain circumstances. This is called extra-label or off-label use because this use is not described on the drug label.
The use of Cough Tablets may not be allowed in certain animal competitions. Always check the rules and regulations before entering your pet in a competition while using this medication.
Speak with your veterinarian about whether Cough Tablets are right for your dog.
How Cough Tablets Works in Dogs
Cough Tablets for dogs is a combination medication containing two active ingredients:
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Dextromethorphan: Dextromethorphan is an antitussive that works by suppressing the cough center in the brain.
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Guaifenesin: Guaifenesin is an expectorant that works by thinning the mucus in the air passages. This helps make a cough more productive, allowing the respiratory system to clear the airways of mucus.
How To Give Cough Tablets to Dogs
Follow the directions on the drug label or as provided by your veterinarian.
This medication may be given with or without food but giving it with food can decrease the risk of digestive upset.
If vomiting occurs or your dog acts sick after receiving Cough Tablets on an empty stomach, the next dose may be given with food or a small treat.
Cough Tablets are generally given every four hours, as the effects do not last very long in dogs.
Missed a Dose?
Speak with your veterinarian about what to do if you forget to give a dose of Cough Tablets.
Generally, your vet may instruct you to give it when you remember, or if it is almost time for your pet’s next dose, to skip the missed dose and resume your normal dosing schedule.
Do not give extra or double doses.
Possible Side Effects of Cough Tablets for Dogs
Cough Tablets are generally well-tolerated in dogs.
The lack of adverse effects is thought to be due to oral dextromethorphan being poorly absorbed in dogs, as shown in a drug absorption study.
Common side effects include:
If these effects become severe, worsen, or continue to be a problem, contact your veterinarian.
Side effects which may be more serious or indicate a serious problem include extreme agitation or nervousness, rapid heartbeat or collapse, and muscle rigidity, tremors, or difficulty walking. If these occur contact your veterinarian immediately.
Human Side Effects
Dextromethorphan/guaifenesin is also an FDA-approved medication for humans, under a variety of brand and generic names, and frequently with dosages different from those prescribed for your pet by a veterinarian.
Due to possible side effects, humans should never use medicine dispensed for their pets and pets should not be given any medicine dispensed or obtained over-the-counter for a human’s use.
Dextromethorphan/guaifenesin for humans often contains additional drugs or ingredients (such as xylitol) that are toxic in dogs.
Avoid handling this medication if allergic to it. Routine hand washing should be performed after handling this medication.
If you accidentally ingest a pet medication, seek medical attention in person immediately and call Poison Control at 800-222-1222.
Monitoring Your Pet
No specific monitoring is required for this medication, but your veterinarian may recommend routine testing depending on your dog’s individual needs, other medications they may be prescribed, and/or the issue that initially caused your dog to be placed on this medication.
When To Call Your Vet
Call your veterinarian if you see any of the following:
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Severe side effects (above)
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Your pet’s condition worsens or does not improve with treatment
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You see or suspect an overdose
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If you have additional questions or concerns about the use of Cough Tablets
Cough Tablets Overdose Concerns in Dogs
Overdoses of Cough Tablets in dogs may cause:
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Involuntary muscle movements, such as tremors or shaking
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Agitation
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Hallucinations
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Nervousness
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Pupil dilation
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Vomiting
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Diarrhea
If you suspect an overdose, immediately seek emergency veterinary care or contact an animal poison control center. Consultation fees often apply.
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Pet Poison Helpline 855-764-7661
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ASPCA Animal Poison Control 888-426-4435
How To Store Cough Tablets for Dogs
Keep the following storage tips in mind for this medication:
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Store at room temperature.
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Keep the container tightly closed to protect from moisture and light.
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Always confirm storage requirements by reading the prescription label.
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Keep out of reach of children and pets.
Cough Tablets for Dogs FAQs
How well do Cough Tablets work in dogs?
Studies have not been performed to evaluate the effectiveness of Cough Tablets in dogs, but most veterinarians feel this medication gives mild to moderate relief to help suppress the cough symptom in dogs with canine infectious respiratory disease (kennel cough).
How long does it take for Cough Tablets to work in dogs?
Most dogs begin experiencing some relief from their cough within one to two hours of taking Cough Tablets. However, its antitussive effects are short-lived, which is why it is important to remember to re-dose every four hours to maintain cough relief.
No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.
References
KuKanich B, Papich MG. Plasma profile and pharmacokinetics of dextromethorphan after intravenous and oral administration in healthy dogs. Journal of Veterinary Pharmacology and Therapeutics. 2004;27(5):337-341.
Plumb DC. Dextromethorphan. Plumb’s Veterinary Drugs. https://app.plumbs.com/drug/uM9CRDfWsRPROD?source=search&searchQuery=dextromethorphan. Updated September 2020. Accessed March 25, 2025.
Plumb DC. Dextromethorphan/Guaifenesin. Plumb’s Veterinary Drugs. https://app.plumbs.com/drug-handout/4nbI8kdqyrp3TD7engBCG0?source=search&searchQuery=guaifen. Accessed March 25, 2025.
