Dog Owner's Home Veterinary Handbook.pdf - Mr. Walnuts

TOXICITY
All drugs are poisons and are capable of causing greater harm than good. This
includes herbal and “natural” remedies. There is a margin of safety between a
therapeutic dose and a toxic dose. A safe drug has a wide margin of safety.
Toxicity is caused by overdose, impaired elimination of the drug, giving the
drug for too long a time, or using a drug with a narrow margin of safety.
If a dog has advanced liver or kidney disease, drugs are not detoxified and
excreted. The dosage of any drug must therefore be reduced accordingly.
Young pups require a lower dose per pound of body weight than do adult dogs,
because puppies’ kidneys are immature.
Drug toxicity can affect one or more systems. Signs are difficult to recognize
in dogs, and can be far advanced before they come to your attention. The
symptoms of drug toxicity include:
• Ears. Damage to the otic nerves leads to ringing in the ears, hearing
loss, and deafness; the hearing loss can be permanent
• Liver. Jaundice and liver failure
• Kidneys. Nitrogen retention, uremia, and kidney failure
• Bone marrow. Depresses the production of red blood cells, white blood
cells, and platelets, resulting in anemia, impaired immunity, and spontaneous
bleeding
• Gastrointestinal. Vomiting and/or diarrhea, nausea, loss of appetite
• Neurological signs. Disorientation, ataxia, coma
ALLERGIC REACTIONS
MEDICATIONS • 565
Antibiotics cause more allergic reactions in dogs than any other group of
drugs. Signs of a mild allergic reaction are hives, rash, itching, scratching, and
watering eyes. Hives are characterized by the sudden appearance of raised, circular
areas in which the hair sticks out in patches. Hives generally appear
within 30 minutes of exposure and disappear within 24 hours. (Other types of
allergic reactions are discussed in Allergies, page 135.) Eruptions on the skin,
hemolytic anemia, or thrombocytopenia from a drug reaction may all be classified
as allergic reactions to a drug.
Anaphylactic shock is an uncommon, severe allergic reaction usually
caused by exposure to foreign proteins, such as penicillin or a vaccine. The
signs are vomiting, diarrhea, weakness, stridor, difficulty breathing, collapse,
and sometimes death. Anaphylactic shock is a medical emergency and is discussed
on page 13.
A dog who has had any type of allergic drug reaction should not be given that drug
again.