Lethargy (tiredness) - If your pet has non-specific lethargy and is not showing any signs of pain, and seems to be acting fine otherwise (i.e. still eating, drinking, going to the bathroom normally), you can usually wait 24 hours. Make sure your pet has nice pink gums. If their gums are pale or white/grey in appearance, then do not wait and call your veterinarian right away.
Vomiting - If your pet vomits one time, but is acting fine otherwise, this is usually not cause for concern. If your pet vomits and has diarrhea, lethargy, decreased appetite, or has gotten into something and/or is just not acting liking themselves, you should call your vet. If your pet vomits more than once in a 24-hour period, you should call your veterinarian right away. The exception to this is if you have a cat that is bringing up a hairball. They will often vomit up more than one hairball in a 24-hour period.
Diarrhea - If your pet has one episode of diarrhea in a 24-hour period and is acting fine otherwise, you can usually sit and wait. If your pet has more than one episode of diarrhea in a 24-hour period, you should call your veterinarian. If you see blood in diarrhea or the diarrhea is black in color, call your veterinarian right away. If your pet has diarrhea and is vomiting, lethargic, has a decreased appetite, has gotten into something, or is just not acting like himself; call your veterinarian.
Decreased Appetite or Anorexia - If your pet has decreased appetite for less than 24 hours and is acting fine otherwise, you can usually wait 24 hours. If your pet is not eating at all, do not wait and call your veterinarian right away. If your pet is acting abnormal and has a decreased appetite, call your veterinarian. If your pet has a decreased appetite or has not eaten for more than 24 hours, call your veterinarian. A decreased appetite or lack of appetite is very serious in cats since they can decline quickly.
Increased Frequency of Urination - If you notice your pet in the litterbox more frequently, asking to go out to potty more frequently, or seeing them urinating more frequently, you should call your vet. If you notice blood in the urine, call your veterinarian. It is also helpful to bring a freshly collected urine sample with you to your appointment. Make sure your pet is producing urine, especially in cats. See decreased urine volume for more information.
Decreased Urine Volume - If you notice your pet trying to urinate more frequently and very little urine is coming out, call your vet. If you notice no urine, call your vet immediately. This is especially true in cats. If you notice a few drops of urine or no urine production, call your veterinarian immediately because your pet could have a urinary obstruction which is a life-threatening emergency.
Increased Appetite - If you notice your pet has an increased appetite, especially in cats, this can be a sign of an underlying problem. If your pet has an increased appetite for more than a few days and it is not due to increased activity, call your veterinarian.
Changes in Weight - If you notice that your pet is losing or gaining weight without any changes in activity or diet, you should take your pet to the veterinarian. There are many conditions that cause weight loss that can become life-threatening if not diagnosed and managed properly. There are also medical conditions that cause weight gain that may need to be managed.
Our pets bring a lot of joy to our lives. They are also very good at hiding illness, pain, etc. If you are at all concerned about the health of your pet, contact your veterinarian. The biggest mistake I see pet owners make is taking a sit-and-wait attitude when it is really something that should have been seen days or weeks before. Cats in particular are great pretenders. They often don’t show how ill they are until they are in dire straits. If you are ever on the fence about whether or not you should call your veterinarian, trust your gut and call. I would much rather tell a pet parent that their furry friend is ok than that we’ve waited too long.