Doxycycline Side Effects in Dogs

Doxycycline is a very strong and effective member of the tetracycline family of antibiotics. While currently not approved for use in animals, many veterinarians prescribe it for certain conditions such as Lyme disease and Ehrlichiosis. It is also used for conditions where the organs have a special barrier in place that prevent other antibiotics from crossing these barriers in order to kill intracellular parasites and infections. Doxycycline doesn’t kill the bacteria, it actually prevents it from reproducing, allowing the dog’s immune system to kill off the bacteria. Doxycycline is also known for having an extended effectiveness, making it highly beneficial in treating particularly difficult conditions.

Doxycycline Side Effects

  • Nausea and vomiting are the most common side effects associated with doxycycline. This side effect can typically be overcome by providing food along with the medication. While most tetracycline-type medications are not given with food because food prevents the antibiotic from being absorbed, this does not seem to be a problem with doxycycline.
  • Loss of appetite is a secondary side effect that goes hand in hand with the nausea and vomiting.
  • Diarrhea is an uncommon side effect of doxycycline. It is frequently an indicator that the dosage is too high and your dog should be taken to the veterinarian to have his dosage adjusted or to determine the cause of the diarrhea.
  • Doxycycline has a pH level that can cause irritation and eventual scarring in the esophagus should the pill get caught in the throat. To avoid this side effect, ask to use the liquid form of doxycycline.
  • Doxycycline can also cause staining or yellowing of the teeth in young animals. Doxycycline binds to calcium, and calcium is the key component in forming teeth.
  • There are some very rare side effects with doxycycline. Changes in blood cells, liver damage and sensitivity to sunlight are extremely rare, but can occur.

Drug Interactions and Precautions

  • Doxycycline can be rendered ineffective when used in combination with other drugs. Medications containing calcium, such as antacids, should be avoided for this reason. The calcium binds to the doxycycline making it ineffective. Dietary supplements containing iron should be given several hours after doxycycline is given because iron can also prevent doxycycline from being effective.
  • If your dog is on digoxin (a heart medication) doxycycline should not be used as it can increase the strength of the digoxin.
  • If your dog’s immune system is in a compromised state, conditions such as kidney disease, diabetes or other conditions that make it difficult for your dog to fight infection, doxycycline should not be used. Another antibiotic should be used in order to keep your dog’s immune system as strong as possible.

Whether your dog is being treated for Lyme disease or a severe kidney or urinary tract infection, if doxycycline is prescribed, it is important to keep an eye on your dog’s progress and how he reacts to this medication. Vomiting and diarrhea can cause dehydration, suppressing his immune system and preventing his body from fighting the infection. It is also important that your veterinarian know what dietary supplements or other over the counter medications you are giving your dog so he can be sure to avoid any negative interactions. Doxycycline can certainly help restore your dog’s health, it should just be used with care.