Doxycycline for Cats

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 Is Doxycycline Used for in Cats?

Doxycycline is a prescription antibiotic medication used to treat a variety of certain susceptible bacterial infections in cats.  

Doxycycline is commonly used to treat: 

• Certain bacterial upper respiratory infections (Mycoplasma felis, Chlamydia felis) 

• Blood infections (Mycoplasma haemofelis) 

• Tick-borne infections (ehrlichiosis, anaplasmosis) 

• Bartonellosis (cat scratch fever) 

• Nocardia infections 

Is Doxycycline FDA-Approved? 

Doxycycline is currently not FDA-approved for use in cats.  

However, it is 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. 

Speak with your veterinarian about whether doxycycline is right for your cat. 

Compounded Doxycycline 

In certain circumstances, your vet may recommend a compounded formulation of doxycycline. 

Compounded medications are prescribed, for example, if:  

• There’s a specific reason your pet’s health can’t be managed by an FDA-approved drug, such as if your pet has trouble taking pills in capsule form 

• The dosage strength is not commercially available 

• The pet is allergic to an ingredient in the FDA-approved medication 

Compounded medications are not FDA-approved. They are formulated by your veterinarian and dispensed either by a licensed pharmacist or veterinarian on an individual basis to best suit a patient’s particular needs. 

Doxycycline Considerations for Cats

Doxycycline should be used with caution in cats with liver disease, as it can elevate liver enzymes. A 2013 study documented increased liver enzyme levels in 19% of cats treated with this medication. 

Doxycycline should also be used with caution in pregnant cats because it can cause birth defects. And in kittens, doxycycline may permanently stain teeth and disrupt bone growth. 

Doxycycline may also cause increased sensitivity to sunlight, so cats taking this medication should avoid direct or prolonged sun exposure. 

Giving doxycycline with certain medications can result in health risks to your cat, so it’s important to discuss your cat’s medications, including vitamins and supplements, and medical conditions with your veterinarian. 

How Doxycycline Works in Cats

Doxycycline is classified as an antibiotic in the tetracycline class. 

Doxycycline works by blocking susceptible bacteria from making essential proteins necessary for their cell walls.  

Without these proteins, the bacteria’s cell walls become compromised, along with their ability to properly replicate and grow.  

How To Give Doxycycline to Cats

Follow the directions on the drug label or as provided by your veterinarian. 

• Doxycycline must be given with food. Try stuffing doxycycline in a pill wrap or treat, like Greenies Pill Pockets. 

• If your cat is taking doxycycline as a tablet or capsule, your vet will recommend giving 5 mL of water by syringe afterward. This helps the medication move from the esophagus to the stomach, reducing the risk of it becoming lodged. 

• Due to the risk of esophageal irritation or ulceration with tablet or capsule formulations, your vet may recommend having doxycycline compounded into a liquid. 

Missed a Dose? 

Speak with your veterinarian about what to do if you forget to give a dose of doxycycline. 

Generally, your vet may instruct you to give it when you remember, or if it is almost time for your cat’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 Doxycycline in Cats

Doxycycline can cause side effects in cats, including: 

• Vomiting 

• Diarrhea 

• Decreased appetite (anorexia) 

• Damage and narrowing of the esophagus, particularly after administration of tablet or capsule formulation 

• Liver enzyme elevation 

Human Side Effects 

Doxycycline is also a prescription medication for humans, 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 for a human’s use.  

If you accidentally ingest a pet medication, seek medical attention in person or 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 cat’s individual needs, other medications they may be prescribed, and/or the issue that initially caused your cat to be placed on this medication. 

When To Call Your Vet 

Call your veterinarian if you see any of the following, or if you have additional questions or concerns about the use of doxycycline:  

• Severe side effects (above) 

• Your pet’s condition worsens or does not improve with treatment 

• You see or suspect an overdose 

Doxycycline Overdose Concerns in Cats

An overdose of doxycycline can cause anorexia or digestive upset such as vomiting or diarrhea. 

Studies have not been performed to evaluate the toxicity of doxycycline in animals. 

If you suspect an overdose, immediately seek emergency veterinary care or contact an animal poison control center. Consultation fees often apply. 

• Pet Poison Helpline 855-764-7661  

• ASPCA Animal Poison Control 888-426-4435  

How To Store Doxycycline for Cats

Keep the following storage tips in mind for this medication: 

• Always confirm storage temperatures by reading the label. 

• Doxycycline should be stored at controlled room temperatures between 68–77 F (20–25 C).  

• Keep the container tightly closed to protect from moisture and light.  

• Compounded medications should be stored according to the compounding pharmacy’s label. 

• Keep out of reach of children and pets.