The Effects of Baytril

An antibiotic of the quinolone family, Bayer HealthCare's Baytril (enrofloxacin) fights a broad range of bacterial and fungal infections in dogs and cats. Baytril's great success has also earned it off-label (not FDA-approved) status as an antibiotic for other small companion animals, including ferrets, rabbits and guinea pigs.


While the beneficial effects of Baytril are many, two serious side effects have limited its use.

  1. Treatment of Respiratory Infections

    • One of Baytril's major effects is its DNA gyrase-inhibiting property. According to Dr. DNA gyrase is an enzyme essential to bacteria's replication process.

      Wound in extremely tight coils, a germ's DNA must unwind for copying before the germ replicates. DNA gyrase facilitates the unwinding process. Baytril inhibits gyrase, the germs die without reproducing, and the infection stops spreading.

      Baytril accumulates rapidly in affected lung and bronchial tissues, so it's ideal for preventing the advance of bronchitis and pneumonia.

    Urinary Tract Infection Treatment

    • Baytril quickly builds up in the urine through kidney excretion. The drug reaches the bladder through both blood and urine, and becomes concentrated at the infection site. Baytril also crosses the blood barrier and fights prostate inflammation, a common cause of urinary tract infection.

    Treatement of Skin Infections

    • Baytril combats the bacteria most commonly found in dog and cat skin infections, including staph, E. coli, pseudomona and pasteurella. It accumulates in infected skin tissue at higher levels and for longer periods than it does in blood plasma.

    Baytril Otic

    • Marketed primarily to treat dogs' outer ear canal infections, Baytril Otic ointment contains both Baytril and silver sulfadiazine. The Baytril quickly kills staph, strep and other bacteria, while the SSD eradicates fungi and may reduce inflammation.

      Combined with oral Baytril tablets, Baytril Otic may also manage middle ear canal infections.

    Baytril Side Effects

    • It has been reported that cats receiving doses of Baytril higher than 5 mg/2.2 lbs. of body weight have suffered retinal damage and blindness.

      Additionally, the high doses of Baytril necessary to control pseudomona-related ear infections have made some dogs nauseous. Veterinarians advise that Baytril may damage cartilage in dogs younger than eight months. Baytril should not be prescribed for growing puppies unless their infections are severe.

      Finally, Baytril can cause urinary crystals, but, unlike struvite or oxalate crystals, they are not potentially harmful.