Strychnine Poisoning Petra A

Strychnine Poisoning Petra A. Volmer, DVM, MS, DABVT, DABT

BASIC INFORMATION that arise following strychnine ingestion. In some cases, strych- Description nine may be found in urine. Strychnine is a bitter alkaloid substance that is extracted from the seeds of Strychnos nux vomica trees. Strychnine is used to control TREATMENT AND FOLLOW-UP populations of ground squirrels, meadow and deer mice, prairie Treatment Options dogs, rats, porcupines, chipmunks, rabbits, and pigeons. Baits con- taining strychnine are often dyed red, green, or blue and are com- Because strychnine can cause a very rapid onset of clinical signs, bined with grain. Availability of over-the-counter versions of the the opportunity to induce vomiting (in order to remove the poison poison varies across the country. Some formulations are available from the stomach) is often lost. Once clinical signs are present, only through licensed pest control operators. vomiting is not induced, because it could cause more harm than Causes and Toxicity good. In some cases, your veterinarian may administer activated Strychnine is quickly absorbed from the gastrointestinal tract, caus- charcoal to try and prevent absorption of the poison. ing rapid onset of clinical signs. Strychnine acts on the animal’s Most affected animals must be hospitalized for emergency nervous system to cause profound stimulation with severe muscle treatment. Muscle stiffness, tremors, and seizures can sometimes spasms and seizures. Strychnine is highly toxic to all animals. be managed with injectable drugs such as anticonvulsants and muscle relaxants. Supportive care may include administration of Clinical Signs intravenous fluids; correction of high body temperatures induced Clinical signs are similar among all animals and can develop as by the muscle tremors and seizures; and respiratory support with quickly as 10 minutes after ingestion (eating the bait). Initially, oxygen or more aggressive measures. animals may appear anxious or nervous, have a rapid rate of Follow-up Care breathing, and have excessive salivation (drooling). Vomiting is uncommon. These signs can rapidly progress to generalized mus- Most poisoned animals must be hospitalized for at least 24-72 cle stiffness, tremors, and seizures. The jaw may be clamped shut hours as they receive treatment. Care should be taken to remove and the neck arched back. The signs may be continuous, or there all bait sources from the animal’s environment. may be brief intervals of relaxation between episodes. Death occurs Prognosis from impaired breathing secondary to muscle stiffness. Depending Prognosis depends on the amount of strychnine ingested and how on the dose ingested, death can occur within minutes to hours. soon the animal receives treatment. If the animal eats a large amount or if treatment is delayed until the animal exhibits severe Diagnostic Tests signs, the prognosis is poor. Many animals die before they receive Diagnosis is based on a history of exposure, consistent clinical appropriate treatment because of the rapid onset of signs. If a signs, and finding strychnine in bait and/or stomach contents on smaller amount is eaten and/or aggressive treatment is started right analysis. There are no specific blood (laboratory) abnormalities away, the prognosis is better.