What are Amoxicillin Allergies?
Amoxicillin is a penicillin antibiotic that is used to treat bacterial infection in dogs as well as humans. Penicillins are a beta-lactam antibiotic that kill bacteria by inhibiting their ability to form a cell wall. Amoxicillin is used to treat infections of the respiratory and gastrointestinal tract, as well as the genitourinary system, skin and soft tissue abscesses. It targets staphylococcus aureus, streptococcus species, E. coli, and Proteus mirabilis among other organisms. Bacteria that produce beta-lactamase will not be affected by amoxicillin, however a combination medicine containing amoxicillin and clavulanic acid (a beta-lactamase inhibitor) may get around this drawback.
Some side-effects like vomiting and diarrhea are fairly common with amoxicillin. Allergic reaction is rarer, but can be more serious. As a penicillin, amoxicillin is one of the antibiotics most likely to cause an allergic reaction, although this is still extremely rare in dogs. Symptoms are typically limited to rash and watery eyes, but serious a life-threatening anaphylaxis is possible. Dogs that have had a prior reaction to another penicillin antibiotic should not take amoxicillin. Other beta-lactam antibiotics, like cephalosporins and cephamycins, should also be avoided, depending on the advice of a veterinarian. If your dog has had a reaction to amoxicillin, or another penicillin, you should mention this to the veterinarian any time an antibiotic is prescribed.
Amoxicillin is a common broad-spectrum antibiotic that is prescribed to dogs for a number of different infections. Penicillin antibiotics, like amoxicillin, have one of the highest rates of allergic reaction in sensitive individuals. Serious reactions are rare, but can be life-threatening.
Symptoms of Amoxicillin Allergies in Dogs
Watch for these symptoms if your dog has just started taking amoxicillin.
- Rash (maculopapular lesions)
- Redness (erythroderma)
- Other types of skin lesion (blisters or scaling skin)
- Itchiness (pruritus)
- Incessant scratching
- Watery eyes
- Runny nose
- Swelling and hives (urticaria-angioedema)
- Purple rash caused by bleeding into the dermal tissue (purpura)
- Anaphylactic shock (rare) (vomiting, diarrhea, difficulty breathing, collapse, death)
Types
There are number of different brand-name amoxicillin medications that deliver the antibiotic in the following ways.
- Tablets or drops – recommended dose is approximately 10-20 mg/kg twice daily
- Injection – recommended dose is 4-10 mg/kg once or twice a day
- Combination tablet with amoxicillin and a beta lactamase inhibitor – recommended dose 10—20mg/kg twice daily
Causes of Amoxicillin Allergies in Dogs
It is not known why some dogs have allergic reactions while others do not. You should look for symptoms of amoxicillin allergies in the following cases.
- Starting amoxicillin treatment for an infection
- Known sensitivity to penicillin or another beta-lactam antibiotic
- General tendency to severe allergic reactions
Diagnosis of Amoxicillin Allergies in Dogs
An amoxicillin allergy will be diagnosed if your dog exhibits symptoms after beginning an amoxicillin regimen, and confirmed if the symptoms resolve themselves when the medication is discontinued. A previous allergic reaction to penicillin or another beta-lactam antibiotics would also be a reason to suspect amoxicillin allergies and avoid the drug. You should always mention previous drug reactions whenever a new medication is prescribed. It’s also a good idea to read through the side-effects and possible responses, so you know what to look for in your dog. If your dog exhibits unusual symptoms after starting amoxicillin or another medication, call the veterinarian and ask for advice. Severe symptoms like excessive swelling, trouble breathing, or collapse should be treated as an emergency.
Treatment of Amoxicillin Allergies in Dogs
If your dog’s symptoms suggest an allergic reaction, the veterinarian will recommend you discontinue taking amoxicillin immediately. Mild symptoms will clear up without further treatment, but the veterinarian may need to prescribe a different antibiotic to fight the original infection.
Severe rashes with blistering and broken skin may need to be treated with topical ointments to prevent further infection. Antihistamines and corticosteroids could also be prescribed to calm the immune system and reduce symptoms.
Dogs with anaphylaxis should be given an epinephrine injection immediately. If you have a dog Epipen at your house, this will help, but your dog will still need immediate treatment. Other emergency measures like additional oxygen, intravenous fluids, and even blood transfusion could be necessary to save your dog’s life. Your dog will need to stay in a veterinary hospital for a day or two until the symptoms have passed and all systems are functioning normally.
Recovery of Amoxicillin Allergies in Dogs
Serious allergic reactions to amoxicillin are rare, and most dogs will make a complete recovery with veterinary treatment. There is no cure for an amoxicillin allergy however, so your dog will need to avoid amoxicillin and other penicillin antibiotics throughout his life. Make sure information about your dog’s allergies is stored in his medical file and mention them specifically anytime you are working with a new veterinarian. Even if your dog hasn’t experienced an allergic reaction, it’s a good idea to watch for symptoms anytime a new medication is started. If your dog has experienced an anaphylactic reaction to a drug or any other allergen, discuss getting a dog Epipen with your veterinarian. An immediate injection administered at home can help your dog survive long enough to get treatment.
Amoxicillin Allergies Questions and Advice from Veterinary Professionals
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My dog was prescribed biomox after she gave birth since she did have some difficulty while going in labor. I have given it to her twice now, and she is breathing heavily and when I am not with her she cries. Right now she seems fine again, regular breathing but I’m not sure if I should still take her in to the vet?
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My vet told me my dog has an upper respiratory infection. He started taking 250mg of Amoxicillin Trihydrate and Clavulanate Potassiuim tablets twice a day for the past 3 days. He seemed fine the first few days, but this morning he was shaking and exhibiting labored breathing. He is also very lethargic. It is Sunday, so my vet is closed, should I take him to the Pet ER for a possible allergic reaction? Thanks!
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Hi, my dog has been taking amoxicillin as per vets instructions for anal gland infection but has started developing symptoms of vomiting several hours after dosing and when taken with food. Should I stop or continue regardless until end of course. Thank u
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My dog 60lbs went to the vet and was told he had an ear infection. could not afford the treatment so I went to the feed store and was given 250mg of amoxicillin. Was wondering how long if he is allergic before I see any problems?? It has been a half an hour since he was given the pill and so far so good.
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It is not just a single dose. I have enough to give it to him for 5-10 days so a pill a day. I was just asking how long if there was a reaction for the reaction to start. He DID NOT get a reaction so I will continue giving him the amoxicillin for the next 5-7 days. That is all.
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My dog ingested a 500mg amoxicillin pill and is very weak, drooling, and looks like she has pain. I don't have money to take her to the vet, but I don't want her to die. Please give me an advise on what should I do?
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Firstly in any case where we suspect that there has been an adverse reaction or undesirable side effect of a medicine we stop administration of that medicine to see if the symptoms decrease in severity; amoxicillin reactions are not uncommon, you would need to visit your Veterinarian regardless of cost to determine whether or not the amoxicillin was the cause and to decide whether to continue giving amoxicillin or to prescribe a different antibiotic (your Veterinarian may also report the event to the manufacturer at their discretion). Regards Dr Callum Turner DVM
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My puppy had a reaction to his vaccine shots and when he had bloody diarrhea the vet prescribed amoxicillin to ward against infection in the intestine walls. Two days after he started amoxicillin his face began to swell and he was treated with an antihistamine, but the vet did not voice the possibility it was the amoxicillin. The next day he began vomiting and experiencing diarrhea again so I stopped treatment as he was barely keeping food down. Since stopping (last dose was last nigh, which he threw up) he has stopped having diarrhea and throwing up. Would a reaction to the medicine occur 2 days after beginning treatment?
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Allergies may occur during the first administration or contact with a substance or after repeated exposure. The swelling maybe related to the amoxicillin or coincidentally to another cause like ingestion of plants, insect allergies, chemical irritants or an environmental factor. The control of the swelling with antihistamines like your Veterinarian prescribed and the administration of a different class of antibiotic would be the step. Try to see if there has been any change in Louie’s environment that may have been related to the swelling. Regards Dr Callum Turner DVM
Why would a vet disregard a Patients question about antibiotics causing severe reactions to our pets? Although it may be "rare" for a pet to go through a severe allergic reaction, it can still happen and no vet should ignore the symptoms, young vets are very arrogant and take questioning too offensively. Getting a well experienced vet from the beginning is highly recommended.
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My dog has a UTI. Can I give him amoxicillin? He's 52 lbs English Bulldog. He had surgery to have his eye removed about a month ago and was given Cipro 500mg twice a day for 14 days. But his urinating has changed in the last week or two
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Amoxicillin is a commonly used antibiotic in Veterinary Medicine; I wouldn’t recommend giving a prescription medicine to Fido without consulting your Veterinarian first as I haven’t examined Fido. There are other causes of urine dribbling include urinary stones, tumours and prostate disorders; I would strongly recommend visiting your Veterinarian before giving amoxicillin to Fido. Regards Dr Callum Turner DVM
My dog ingested a 500mg amoxicillin pill and is very weak, drooling, and looks like she has pain. I don't have money to take her to the vet, but I don't want her to die. Please give me an advise on what should I do?
Our daughter was prescribed amoxicillin for an ear infection and when trying to give it to her on the spoon yesterday a very small amount went on the floor - we think our dog (5 yr old corgi) has licked it up. Today she has had swollen eye lids and a very swollen muzzle. She is squeaking in discomfort. Saw emergency vet earlier tonight before connecting the sudden illness with the amoxicillin. Vet said to just wait for the reaction to wear off. Knowing that this is a possible cause should we still follow this advice? Vet thought she might have eaten a wasp. Muzzle swelling has gone down now significantly. Advice appreciated!
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