Toxicology Brief: The 10 most common toxicoses in dogs


Toxicology Brief: The 10 most common toxicoses in dogs

Dogs are usually exposed to potentially toxic household products and medications accidentally. But sometimes well-intentioned owners unknowingly give their dogs harmful products and medications. To help prepare you for patients with theses toxicoses, we compiled this list of the 10 most common hazards to dogs, based on the number of calls we have received at the ASPCA Animal Poison Control Center (APCC) between 2001 and 2005.1


Ibuprofen, a nonsteroidal anti-inflammatory drug with analgesic, anti-inflammatory, and antipyretic effects,2 is available in a variety of strengths. The most common over-the-counter strength is 200 mg, but the prescription-strength tablets can contain up to 800 mg ibuprofen. Ibuprofen has a narrow margin of safety in dogs, and acute toxicosis is common. Dogs are often exposed to ibuprofen accidentally when they chew on a medicine bottle, but sometimes owners give ibuprofen to their dogs intentionally for pain control.

Ibuprofen overdose can cause GI, renal, and central nervous system (CNS) effects. Doses of 25 mg/kg or more often lead to gastrointestinal (GI) problems and ulceration, manifested as vomiting, diarrhea, or abdominal pain. Doses approaching 175 mg/kg increase a dog's risk of developing acute renal failure,2 but older dogs or those with preexisting renal compromise may exhibit renal failure at lower doses. With doses greater than 400 mg/kg, CNS effects such as depression, seizures, and comas may occur.

Treatment for acute ibuprofen toxicosis includes inducing emesis, administering activated charcoal (multiple charcoal doses are indicated to reduce enterohepatic recirculation in dogs that have ingested high doses of ibuprofen) and GI protectants (H2-blockers, sucralfate, misoprostol), and inducing diuresis with intravenous fluids at twice the maintenance rate while monitoring renal function. With timely and appropriate treatment, most dogs are expected to have a positive outcome.


Chocolate contains two types of methylxanthine, theobromine and caffeine, with their amounts varying depending on the type of chocolate. For example, milk chocolate contains about 60 mg/oz methylxanthine, dark chocolate about 150 mg/oz, and baking chocolate about 450 mg/oz.3

Clinical signs of chocolate ingestion range from GI upset to cardiovascular effects (e.g. tachycardia, hypertension or hypotension, arrhythmias) to CNS signs (e.g. agitation, pacing, hyperactivity, tremors, seizures). The toxicity depends on the type of chocolate, the amount ingested, the size of the animal, and the animal's sensitivity to methylxanthines. Mild stimulation such as hyperactivity, agitation, and restlessness may occur in dogs ingesting around 20 mg/kg methylxanthine. Cardiotoxicosis may occur in dogs ingesting 40 mg/kg, and dogs ingesting more than 60 mg/kg may exhibit severe CNS signs, such as tremors and seizures.3 GI signs such as vomiting and diarrhea can occur with any amount because of chocolate's high fat and sugar content.

Treating chocolate ingestion includes inducing emesis or performing gastric lavage, administering activated charcoal (multiples doses are recommended with large ingestions), monitoring the patient's vital signs closely, and providing supportive care. Continuous electrocardiogram (ECG) monitoring is advisable in cases in which cardiotoxicosis is expected. Performing baseline serum chemistry profiles and monitoring electrolytes in symptomatic animals are also recommended. Dogs should be stabilized before you initiate decontamination procedures. Administer intravenous fluids to enhance methylxanthine excretion, beta-blockers (e.g. propranolol, metoprolol) to reduce tachycardia, and diazepam to control agitation and tremors. Methylxanthines can be reabsorbed from the bladder, so monitor urine output and consider placing a urinary catheter to keep the bladder empty. Signs can last 24 to 72 hours because of the long half-life of theobromine in dogs (17.5 hours vs. 4.5 hours for caffeine).3