Doxycycline is a semi-synthetic tetracycline antibiotic, derived from oxytetracycline. It may be used orally (dogs, cats and horses) or intravenously (dogs and cats). Tetracycline antibiotics are broad-spectrum and bacteriostatic. Their mechanism of action is through the inhibition of protein synthesis, and the alteration of cytoplasmic membrane permeability within the susceptible organism. Doxycycline is more lipid-soluble than other tetracycline antibiotics and may reach higher levels in some of the difficult to penetrate areas, such as synovial fluid, central nervous system, prostate, and the eyes.

Tetracycline antibiotics, including doxycycline, are effective against a broad spectrum of gram-negative and gram-positive bacteria, and wide variety of other organisms including Rickettsia, Spirochetes, Mycoplasma, Leptospira, Anaplasma, and Chlamydia. In addition to its use as an antibiotic, doxycycline is used in low doses as an anti-inflammatory and adjunct treatment for arthritis and degenerative joint-disease in dogs and horses. This use is based on the inhibition of metallo-matrix proteinases. Doxycycline is well-absorbed after oral administration and its absorption is minimally affected by the presence of food in the stomach. Doxycycline may be used in animals with decreased kidney function because it is eliminated primarily via the GI tract.


Doxycycline (brand names: Vibramycin®, Oracea®, Monodox®, Periostat®, Doryx®, Acticlate®) is a tetracycline antibiotic used to treat certain infections in small animals, such as anaplasma (a tick-borne disease), heartworm disease, and periodontal (teeth and gum) disease.

Its use in cats, dogs, small mammals, reptiles, or birds to treat infections is ‘off label’ or ‘extra label’. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

Features of Doxycycline For Cats

Doxycycline is given by mouth in the form of a tablet, capsule, or liquid. If administering liquid forms, be sure to measure the medication carefully. When administering the tablets, the pill should be followed by at least 6mL of water or food – never give the pill dry. This is particularly important in cats.

To ease stomach upset, give this medication with food, and do not give with food containing dairy or iron, as calcium and iron can block the medication’s efficacy.

This medication will take effect quickly, in about 1 to 2 hours, however, visible effects may take a few days to be recognized.

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.

Uses/benefits of Doxycycline For Cats

Doxycycline is commonly prescribed because it treats a variety of infections and is generally well-tolerated by both cats and dogs. It may be prescribed for respiratory tract infections, skin/dental infections, kennel cough, tick-borne diseases, and heartworm disease.

Side effects of Doxycycline For Cats

Like most medications, doxycycline may come with side effects. Side effects are usually mild, but using doxycycline in combination with other drugs may exacerbate the side effects. Here are the most common side effects of doxycycline for cats:

  • Nausea
  • Vomiting
  • Discoloration of teeth
  • Diarrhea
  • Throat irritation (from dry pilling methods)
  • Liver failure


  • Medication type: Antibiotic
  • Form: Liquid, Capsule, Pill
  • Prescription required? Yes
  • FDA approved? Not approved for use in cats (dogs only) in the United States.
  • Life stage: All
  • Brand names: Adoxa, Alodox, Atridox, Doryx, Doxy, Monodox, Oracea, Oraxyl, Periostat, Vibramycin, Vibravet, Virbra-Tabs, Doxirobe
  • Common names: Doxycycline, Doxycycline hyclate, Doxycycline hydrochloride, Doxycycline monohydrate
  • Available dosages: Capsules: 20 mg, 50 mg, 100 mg; Tablets: 20 mg, 100 mg; Oral suspension 5 mg/mL, 10 mg/mL (liquid)
  • Expiration range: See bottle label for expiration. Reconstituted liquids are good for only 2 weeks.

Prices of Doxycycline For Cats

$10.23 – $39.99

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