Strychnine Poisoning in Cats

Strychnine is a toxin derived from the seeds of Strychnos nux vomica and S. ignatii, used to control rats, moles and other predators. However, when ingested by cats, it is extremely toxic, and can cause death.

Direct exposure to bait is the most common cause in cats, although intentional poisonings are not uncommon. Toxicity can also occur from the ingestion of poisoned rodents and birds.

The primary effect of the toxin is on the neurological system. The toxin interferes with inhibitory transmitters, which produce a state of muscle rigidity and stimulation. Death is often caused by the effect on muscles that stimulate breathing.

What to Watch For

• Violent seizures
• Rigidity
• Muscle stiffness
• Fast heart rate
• Difficult or slow breathing
• Cessation of breathing and death

Diagnosis

Routine blood tests are often completed to rule out other diseases that can cause similar symptoms. Routine baseline diagnostics are usually within normal limits, at least initially. In addition:

• An electrocardiogram may reveal tachycardia.
• Measuring blood pressure often reveals severe hypertension (high blood pressure).
• The stomach contents reveals presence of strychnine; bait is often colored red, blue, or green, and identifying it is often the only definitive way of documenting strychnine poisoning.

Treatment

Decontamination is important in decreasing the duration and severity of signs. Gastric lavage (flushing/rinsing of the stomach) and the administration of intravenous fluids are recommended.

Controlling seizures and preventing asphyxiation are most important. Heavy sedation, general anesthesia and artificial respiratory support may be required.

Maintaining the patient in a quiet dimly lit room may be of benefit.

Home Care and Prevention

If you witness your cat ingesting strychnine, contact your veterinarian at once. He or she may direct you to induce vomiting immediately, if it is within minutes of ingestion. Take all poison packages with you to your veterinarian's office.

Most importantly, to prevent exposure, do not allow exposure to bait.