A common reason pet families bring their pets to the veterinarians at the Animal Medical Center is an increase in water consumption, or polydipsia in doctor speak. If the pet family doesn’t mention water consumption, the veterinarian will usually ask about any changes in water drinking habits. In today’s post, I outline some of the more common causes of increased water drinking. While an increase in water consumption may signal a serious medical condition, sometimes the increase is a normal physiologic condition.
Too Much In Or Too Much Out?
Increased drinking can occur because of excessive loss of fluid in the urine or because of a condition that increases the stimulus to drink water. The former is much more common and, from a veterinary perspective, much easier to diagnose than the latter.
A number of drugs frequently prescribed for dogs and cats increases water intake. They include: prednisone (or any steroid), phenobarbital and Lasix® (furosemide), which is a diuretic. Obviously, Lasix® increases urine output, causing your pet to drink more water. Similarly, steroids impact the kidney’s ability to conserve water resulting in increased thirst. Why phenobarbital, an antiseizure medication causes polydipsia is unknown.
Hot Dogs, Cool Cats
On a hot day, your dog pants to cool off. Panting evaporates saliva from the mouth, but leaves your dog very thirsty to replenish the body’s water supply. Fever will do the same thing. Your dog or cat loses body fluids through panting or their sweaty little paws and they will drink more to compensate.
Increased water intake frequently happens with a diet change for your pet. Canned food is approximately 75-80% water. Switching from a canned diet to a dry diet will cause a noticeable increase in water drinking. Swap your pet’s canned food for dry and your dog or cat will need to replace the water previously consumed in food by drinking more. Switch from dry food to canned food and you will notice you need to fill the water bowl less often.
A prescription diet to dissolve bladder stones works in part because it has been formulated to promote water consumption. Increasing urine production lowers the concentration of stone-forming minerals in the urine and dissolves the bladder stones. The stone-dissolving diet contains low concentrations of minerals found in bladder stones and must be used under the guidance of a veterinarian and with proper patient monitoring.
In unspayed female dogs, pyometra, or a severe uterine infection, causes increased loss of fluid through the kidney and a compensatory increase in water consumption. The bacterium associated with pyometra is E. coli. This bacterium produces a toxin that impairs the kidney’s ability to regulate water and increases urine output. Female dogs with pyometra often come to the veterinary clinic because the family notices an increase in water intake in response to the increased urine output.
If you think your pet is drinking more water than normal, see your veterinarian as soon as possible and take along a urine sample from your pet. Your vet will thank you.