Strychnine is a neurotoxin which exerts most of its toxic side effects on the brain and spinal cord. 

Symptoms may occur within 15 minutes to two hours of ingestion of strychnine. These signs can include twitching and seizures.

Treatment consists of controlling the seizures, removal of the toxin and supportive care.

Prognosis is guarded to good depending on how promptly treatment is started with respect to time of intoxication.  

What is it?

• Strychnine is most commonly used as a rodenticide (mouse and rat poison).   It is marketed as “treated” seeds or pellets which are often dyed pink, green or yellow to signify their toxic nature and also to deter consumption by birds.  
• It is approved for below ground use only and it is most commonly used to bait gophers and ground squirrels.  
• Intoxication occurs by either direct ingestion of the toxin (primary) or ingestion of an affected animal (secondary or relay toxicosis).  
• Strychnine may be used in malicious poisonings where the seeds are placed in meat balls and fed to the patient.
• Strychnine is a neurotoxin which exerts most of its toxic side effects on the brain and spinal cord. 
• It’s mode of action is to antagonize or block glycine which is an inhibitory neurotransmitter found in the brain and spinal cord.   Since inhibition is lost, the victim's muscles may begin to spasm uncontrollably and death ensues (because the animal cannot breathe).  

Clinical Signs

• Signs may occur within 15 minutes to two hours of ingestion of strychnine.
• Muscle twitching/tics
• Extreme sensitivity to sudden noise or bright light
• Nervousness
• Restlessness
• Sudden and explosive tetanic/rigid seizures (sawhorse stance)
• Asphyxiation (can't breathe) which leads to death

Diagnosis

• Definitive diagnosis is made by toxicology screening of stomach contents, urine or liver tissue for strychnine.  This test must be performed by a reference laboratory.
• Clinical signs allow a presumptive diagnosis so that treatment can be instituted.

Treatment

• Treatment consists of controlling the seizures, removal of the toxin and supportive care.  
• The seizures must be controlled with medication such as pentobarbital and some patients must be completely anesthetized to control seizures.  
• Once the seizures are controlled, gastric lavage (pumping the stomach) is necessary to evacuate any toxin that may remain within the stomach.  
• Activated charcoal is then administered to prevent further absorption of any remaining toxin.  
• Note:   The induction of vomiting is usually not recommended as this may stimulate seizures and result in complications such as aspiration pneumonia.  
• If the patient is still exhibiting clinical signs after the gastric lavage, narcotics and/or muscle relaxants may be used.  
• The patient should be kept in a warm and quiet environment to decrease external stimuli.   Cotton balls or ear plugs may be placed in the patient’s ears to decrease auditory stimuli.  
• Patients are usually administered intravenous fluids to aid in elimination of the toxin by the kidneys.

Complications

• Hyperthermia (elevated body temperature) due to uncontrolled muscle tremors or seizures which can cause brain damage.
• Asphyxiation (inability to breath) which results in death.  
• Myoglobinuria (port wine colored urine) may be present due to acute destruction of muscle cells.

Aftercare

• Aftercare or home care is generally not needed.  
• The owner should attempt to find the source of intoxication including malicious baiting, illegal use of toxin-laced seeds above ground or areas where the pet may have exhumed bait that was placed below ground.  
• Other pet owners in the area should be notified in case of exposure to one of their animals.  
• Follow up care with your regular veterinarian will be determined by the severity of the toxicosis and any complications which may have occurred.

Prognosis

• Prognosis is guarded to good depending on how promptly treatment is started with respect to time of intoxication.  
• A patient should be hospitalized for 24-48 hours for supportive care.