Strychnine Flashcards
Is strychnine a general use or restricted use pesticide?
restricted use
not as common as other toxicants but can be used maliciously
Is strychnine an acid or a base?
Weak base - will be absorbed and non ionized when it is in an alkaline environment
T/F: Strychnine may cause vomiting when ingested
TRUE
What is the rate of strychnine absorption?
RAPID
no tissue accumulation
What is the toxic dose of strychnine in dogs?
0.5 - 1.2 mg/kg
HIGHLY TOXIC
Why would food in the stomach increase or decrease the toxicity of strychnine when ingested?
Increase toxicity: food in the stomach may decrease the chance of vomiting and auto decontamination
Decrease toxicity: food in the stomach may slow absorption
Does strychnine cross the BBB?
YES
Where is strychnine metabolized and excreted?
In the liver and excreted in the urine - unchanged and as metabolites
Most of the does is eliminated within 24 hours
Does undergo enterohepatic recirculation
What is the MOA of strychnine?
Block post synaptic effect of glycine on the spinal cord
(glycine is an inhibitory neurotransmitter to motor neurons and interneurons in the CNS
Leads to: exaggerated reflex arcs, muscle spasms, severe extensor rigidity, tonic seizures
What clinical signs are observed in a patient with strychnine poisoning?
Rapid onset - 10mins - 2 hrs and rapid death
Early: apprehension, panting, nausea/vomiting, mydriasis, stiffness, muscle twitching, hyperthermia
Progresses to tonix sz, opisthotonos
death from respiratory failure
Are seizures caused by strychnine poisoning elicitable?
YES
by external stimuli (light, touch, sound)
What lesions are associated with strychnine poisoning?
Generally few or no lesions
hemorrhage, cyanosis, congestion,
rapid rigor mortis
stomach contents may still contain bait
What are the preferred specimens for chemical detection of strychnine?
antemortem: stomach contents, bait, serum, urine
Post mortem: stomach contents, liver
$$$$$$/5-7 day turn around time
What is the treatment protocol for strychnine poisoning?
Decontamination - Emesis: if patient is neurologically normal, gastric lavage (avoid bicarb or antiacids)
Activated charcoal - repeated doses
*can enhance renal excretion with ammonium chloride or methionine
Supportive: IVF, O2, Muscle relaxors and anticonvulsants, keep patient in a calm environment
avoid opiods/NMB/ketamine
What is the prognosis for strychnine toxicosis?
Good if the patient presents early and aggressive therapy is started - therapy or at least 24-72 hours
