Unfortunately, no specific drugs treat dogs with the distemper virus. Instead, dogs should receive supportive care and treatment that helps prevent additional infections from developing while the white blood cells are suppressed (lymphopenia). For example, antibiotics are given to help prevent pneumonia.
Most dogs need IV fluids because they are not eating and may have diarrhea. Dogs with seizures are given anti-seizure medications such as diazepam or phenobarbital (both controlled substances), or potassium bromide. Steroids are not routinely used because they increase the chance of secondary infection, but when your dog has severe seizures, sometimes steroids are necessary. There are no effective anti-viral drugs for distemper.
Distemper is easier to prevent with vaccination than it is to treat. Distemper vaccines are made either with the live or killed virus. With live virus vaccines, a weakened form (attenuated) of the virus is injected to stimulate the white blood cells to make antibodies to fight the infection. Live virus vaccines promote long-lived immunity and nearly 100% of vaccinated dogs will be protected from developing the disease. However, there are rare cases of fatal brain inflammation (encephalitis) in dogs given the live vaccine. The killed vaccine is safer, but 20-30% of vaccinated dogs will not develop an immune response that can protect them from the distemper virus when vaccinated with a killed product.
Vaccination for distemper is also complicated by the fact that regardless of whether a killed or live vaccine is used, a puppy cannot develop an immune response if the antibodies to distemper were absorbed from colostrum. Colostrum is the first 12-24 hours of mother's milk that is high in protective antibodies. If antibodies from colostrum are still circulating within your puppy's bloodstream, the vaccine is immediately neutralized so your puppy's cells do not learn how to fight the infection. Some puppies receive a strong dose of protective antibodies from colostrum and other puppies receive very few. We cannot tell by looking at puppies what their antibody levels are. Vaccines need to be timed just right so that they stimulate your puppy's immune system just at the time the maternal antibodies have declined and no longer protect your puppy, but before your puppy has been exposed to the easily spread virus.
In the past, veterinarians tried to provide vaccines at the right time by giving them to your pet every two weeks between the age of six and 12 weeks. That way, puppies in the litter without much colostrum-provided protection were covered by the first shots and puppies that consumed a lot of colostrum and had strong protection were covered by the last shots. New research indicates that this practice of repeatedly vaccinating is harmful.
Often dogs are given one vaccine that protects from several diseases at the same time. These are called polyvalent vaccines. Some veterinarians advise against using polyvalent vaccines because they can overwhelm a pet's immune system and cause health problems. In nature, an animal is never exposed to multiple diseases at the same time. Among the health problems proven to be caused by over-vaccinating are cancers, immune-mediated hemolytic anemia, and probably thyroid diseases. Work with your veterinarian to create a vaccine plan that prevents over-vaccinating. Some veterinarians are now asking pet owners sign consent forms to make sure they understand that vaccinating has risks as well as benefits.
It may be best to draw blood and have a laboratory measure your dog's level of antibodies to distemper. These tests are called titers. If the titer is at a protective level, your dog would not benefit from a vaccine. This way, you determine when, and if, your dog should be vaccinated. Discuss the benefit of titers with your veterinarian and decide together which vaccines should be used and how often they should be given.
Breeding females can be vaccinated about two weeks before mating so that puppies will receive a high level of antibodies in colostrum. These antibodies protect tiny pups with their immature immune systems during the period they are most susceptible to infections. Puppies born to dogs that were vaccinated just prior to mating usually have high levels of circulating antibodies so that they do best when their first vaccine is closer to 12 weeks of age. If a breeding female already has high levels of protective antibodies, she does not need the vaccine before mating.
Prevention of distemper requires a healthy lifestyle just as much as it requires vaccines. Good nutrition via high quality dog food, quiet peaceful sleep on a good pet bed, vigorous playtime with dog toys, and healthy supplements all contribute to a healthy lifestyle for your dog.