Lethargic Dog: Is Your Lethargic Dog Causing You Concern?

We love our dogs for the energy and joy that they bring to our lives and there are few things worse than seeing our friends show signs of lethargy and weakness. For most pet parents, this is a red flag that something may be wrong, but it is sometimes difficult to figure out what it is that is causing the problem. If your dog is showing signs of being lethargic or weak, contact your family veterinarian as soon as possible. There are many different issues that could be causing either lethargy or weakness, including a chronic condition or even a life-threatening illness.

The presence of lethargy and weakness may be indicative of a broad range of conditions relating to the following:

  • Infection
  • Organic or metabolic disease
  • Medication

Each of these categories includes a host of specific causes, each of which may be treated differently depending on the nature of the condition.


The presence of any kind of infection may result in signs of lethargy and weakness in your dog. These infections can be extremely serious, and they are certainly not to be taken lightly. They may include:

  • Parvovirus – This is an infection that is spread through feces. In addition to lethargy, symptoms of parvovirus include diarrhea, vomiting and abdominal pain. The treatment for this infection includes antibiotics, anti-nausea medications and fluids.
  • Kennel cough – This respiratory disease is contagious and is most commonly characterized by a dry, honking cough. The treatment may include antibiotics, bronchodilators and cough suppressants.
  • Distemper – The signs of distemper are quite varied and therefore differ from dog to dog. The treatment options include antibiotics, anticonvulsants and fluids.
  • Heartworm – This parasite is transmitted through mosquito bites. The common symptoms include fever, depression, lethargy and weakness. Since the treatment includes many injections and an extended period of cage rest, having your pet take a regular heartworm prevention (available through your family veterinarian) is strongly recommended.

Metabolic and Organic Diseases

Certain chronic conditions that may become progressively worse over time if not properly treated, include:

  • Heart disease
  • Liver disease
  • Renal Disease
  • Anemia
  • Hypoglycemia
  • Diabetes mellitus

Accompanying each of these conditions is a series of symptoms and each condition can result in a weak or lethargic dog.


Some prescription medications may cause your dog to feel lethargic, so if you notice any such symptoms after beginning new medication, call your family veterinarian as soon as possible. Of course, human medications can be toxic to dogs, so take great care in keeping these out of the reach of your dog and always properly dispose of them.

There are many causes of dog lethargy, and in all cases it is best to contact your family veterinarian as quickly as possible. With the appropriate care and treatment, your dog could be back to playing again in no time.