Amoxicillin dosage for dogs: Dosages, safety, and guidelines

Amoxicillin is one of many beta-lactam antibiotics, a type of penicillin, and a prescription medication that treats bacterial infections in the ear, nose, throat, sinuses, lower respiratory tract, skin, skin structures, and urinary tract. It cannot treat viral infections. While often used in human patients, amoxicillin is generally safe for dogs, too. Veterinarians may prescribe it as a treatment for the same condition: an infection. The amoxicillin dosage for dogs is usually around 5 mg per pound, twice a day.

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How much amoxicillin can I give my dog?

Small dogs and large dogs won’t take the same dose of amoxicillin. The standard dosage of amoxicillin for dogs is 5 mg per pound the dog weighs, twice daily (so two times every 24 hours). The form depends on their weight, too, as well as their age, but is taken by mouth either way. “Larger and older dogs will tend to get the tablet form of the medication, whereas younger and smaller dogs will often get a liquid form,” clarifies Dr. Dwight Alleyne, DVM, a veterinarian and JustAnswer veterinarian expert.

As a tablet (aka Amoxi-tabs), amoxicillin can be given without food. After oral administration, the drug is rapidly absorbed and diffused into most body tissues and fluids.

It’s important to note that amoxicillin can have some side effects in dogs, such as diarrhea, vomiting, loss of appetite, or an allergic reaction. Signs of an allergic reaction to amoxicillin include fever, rashes, trouble breathing, and trouble walking. Dog owners should consult a veterinary professional at the first sign of an allergic reaction since it can cause more serious side effects, such as anaphylaxis. If the dog has a history of an allergic reaction to this medication or similar medications, talking to a veterinarian before administering the amoxicillin is crucial.

If and when it’s time to grab the medicine, animal owners can fill pet prescriptions at the vet’s office, from an online pet pharmacy, or at their local pharmacy. With a SingleCare prescription discount card, medications such as amoxicillin can be purchased at a reduced cost.

Soft tissue infections

• First, amoxicillin can treat general bacterial infections, such as a soft tissue infection, in dogs. “Bacterial infections can be caused by a variety of bacteria entering the body through wounds, indigestion, or inhalation,” says Dr. Nita Vasudevan, DVM, a veterinarian and veterinary consultant for Embrace Pet Insurance. She adds that symptoms can include fever, lethargy, loss of appetite, localized redness, swelling, and discharge. So how does amoxicillin help? She says it’s “a broad-spectrum antibiotic that works by inhibiting the synthesis of bacterial cell walls, thereby killing the bacteria.”

• The human form has the same active ingredient as the pet form of amoxicillin, but that doesn’t quite mean you can give your dog leftover amoxicillin from your cabinet. The form of amoxicillin taken by humans can also be taken by dogs if under the supervision of a veterinarian, according to Dr. Vasudevan. “The formulation, frequency of administration, and dosage in human medications can differ significantly, potentially leading to improper dosing or harmful additives,” she says.

• Standard dosage of amoxicillin for dogs with bacterial infections: 5 mg per pound the dog weighs, every 12 hours

• Maximum dosage of amoxicillin for dogs with bacterial infections: The maximum dosage can vary greatly depending on the type of infection and the dog’s size.

Skin infections

• Dogs can get skin infections caused by bacterial infections, says Dr. Alleyene. Symptoms may include red raised bumps on the skin and hair loss. “Amoxicillin can help kill the bacteria, decreasing inflammation of the skin and allowing the skin to heal,” he explains.

• Between 20% to 75% of cases in the average animal practice are primarily related to skin problems in small animals, according to information compiled in the Veterinary Research Forum.

• Pet owners can give their dogs the human form of amoxicillin under veterinary supervision, Cox says. “There is no need for a special formulation.”

• Standard dosage of amoxicillin for dogs with skin infections: 5 mg per pound every 12 hours

• Maximum dosage of amoxicillin for dogs with skin infections: 10 mg per pound every 12 hours

Urinary tract infections (UTIs)

• UTIs in dogs are caused by an overgrowth of bacteria in the bladder, Dr. Alleyne says. Typically, it’s Escherichia coli (E. coli) that ascends the urinary tract, according to Dr. Vasudevan. Proteus mirabilis is a bacterium and a common cause, too. Common symptoms of UTIs include frequent urination, blood in the urine, straining to urinate, and discomfort or pain while urinating. Dr. Vasudevan says amoxicillin “eliminates the bacteria causing the infection, relieving symptoms and preventing complications.”

• Up to 27% of dogs will get a UTI at some point, and they’re more common in female dogs, according to a study in the Journal of Small Animal Practice.

• The human form of amoxicillin is safe for dogs to take, but only under a veterinarian’s direction.

• Standard dosage of amoxicillin for dogs with urinary tract infections: 5-7 mg per pound every 12 hours for three to seven days. A longer course (up to two weeks) may be considered if infections persist or return.

• Maximum dosage of amoxicillin for dogs with urinary tract infections: 10 mg per pound every 12 hours

Upper respiratory infections

• Upper respiratory infections are caused by a viral or bacterial infection in the trachea or lungs, Dr. Alleyne says. Typical culprits, according to Dr. Vasudevan, are Bordetella bronchiseptica or secondary bacterial infections after a viral infection. Staphylococcus aureus is another bacterium that can lead to this type of infection. Common symptoms of upper respiratory infections include coughing, sneezing, difficulty breathing, and nasal discharge. “Amoxicillin can help decrease the symptoms by killing the bacteria that is involved,” Dr. Alleyne explains.

• Upper (and lower) respiratory tract infections are commonly diagnosed in veterinary offices.

• Dogs can also take the human form of amoxicillin for upper respiratory infections if under the supervision of a vet.

• Standard dosage of amoxicillin for dogs with upper respiratory infections: 5 mg per pound every 12 hours for five to seven days

• Maximum dosage of amoxicillin for dogs with upper respiratory infections: 10 mg per pound every 12 hours

What is the maximum amoxicillin dose for dogs by weight?

The max amoxicillin dose that a dog can take will depend on its weight. As Dr. Alleyne mentioned earlier, the maximum dose is around 10 mg per pound, regardless of breed. This means the maximum dose for a small two-pound dog could be as low as 20 mg, while a large 120-pound dog would have a maximum dose as high as 1,200 mg.

Dr. Vasudevan adds it can also vary based on the specific condition and health status, which will be individual to each dog. A dog owner’s best bet is to discuss their dog’s health history with a veterinarian.

Can dogs overdose on amoxicillin?

Unfortunately, dogs can overdose on amoxicillin. The vets say the most common signs are digestive issues, such as vomiting, diarrhea, and loss of appetite, as well as lethargy.

If any of these symptoms become apparent after taking amoxicillin, Dr. Alleyne says, pet owners should seek medical attention. Dr. Vasudevan agrees and adds another resource: the veterinary toxicologists working with the pet poison helpline. The ASPCA Animal Poison Control Center’s phone number is (888) 426-4435. There is also the Pet Poison Helpline at (855) 764-7661. Both are available to advise 24 hours a day, 365 days a year.

How often can I give my dog amoxicillin?

Thankfully, there aren’t too many numbers or amounts to remember—and knowing what they are is more of the vet’s job, anyway. “The starting dose and the maintenance dose are typically the same for each of these conditions,” Dr. Alleyne says.

Further, Dr. Vasudevan says that amoxicillin is rarely used chronically since chronic use could lead to the development of antibiotic-resistant bacteria. While a dog is taking it, however, be sure to keep the prescription at room temperature.

The maximum dose is usually around 10 mg per pound, but it can also vary.

As far as the dosing schedule for amoxicillin in dogs, Dr. Alleyne says you’re looking at about every 12 hours, while Dr. Vasudevan says anywhere from every 12 to 24 hours. “The exact schedule depends on the infection being treated and the veterinarian’s instructions,” she says. “It’s crucial to complete the full course of antibiotics as prescribed to prevent resistance and recurrence of the infection.”

• Amoxi-tabs, DailyMed (2020)

• Amoxicillin/Clavulanate, Plumb’s Veterinary Medication Guides (2020)

• Lifestyle as risk factor for infectious causes of death in young dogs: A retrospective study in southern Italy, Veterinary Medicine International (2020)

• Survey of dermatological conditions in a population of domestic dogs in Mashhad, northeast of Iran, Veterinary Research Forum (2013)

• Canine bacteriuria, Journal of Small Animal Practice (1977)

• A review of the pathology and treatment of canine respiratory infections, Dovepress (2012)

• Animal Poison Control, American Society for the Prevention of Cruelty to Animals (2024)