Marijuana, known by many names, needs very little introduction; we all know it is a popular recreational drug smoked illegally by millions of people worldwide. Its psychoactive ingredient is delta 9-tetrahydrocannabinol, more commonly called “THC.” Regular marijuana is typically 1-8% THC while hashish, made from the flowering tops of the plant and their resins, can contain up to 10% THC. Other properties of THC give it controversial medicinal properties: appetite stimulation and nausea control.
The usual pet toxicity case involves a dog that has inadvertently eaten a stash of marijuana. In the dog, clinical signs typically begin 30-90 minutes after the marijuana has been eaten. Because THC is stored in the body’s fat deposits, the effects of marijuana ingestion can last for days.
Signs include: incoordination and listlessness along with dilated pupils, slow heart rate and sometimes urinary incontinence. A characteristic startle reaction has been described where the pet appears drowsy and even may begin to fall over but catches balance. Marijuana toxicity can look similar to intoxication with numerous other sedatives. It is very important for all the relevant information to be presented to the veterinarian if the pet is to be helped; veterinarians are not obligated to report to local police. If you know marijuana was involved in an intoxication it is important to make this information known to the attending doctor. Obviously this goes for other recreational drugs as well.
Urine testing similar to that done with humans can be done in dogs to make the diagnosis of marijuana intoxication. Test kits are available at most drug stores and can include assays for a number of recreational drugs. A relatively large volume is needed to run these tests if the pet is small and this may be difficult to obtain, particularly in a female. Also, false negatives are common when the THC urine test is performed on pet urine; a positive is confirmatory but the diagnosis can often be made based on the history and clinical picture even if the test is negative.
If less than thirty minutes have passed since the marijuana has been eaten it may be possible to induce vomiting but after symptoms have started, the nausea control properties of THC make it very difficult to induce vomiting. Further, if the patient is extremely sedated, vomiting can be dangerous as vomit can be inhaled and cause a very serious and deadly aspiration pneumonia.
Activated charcoal is a liquid material used in the treatment of poisoning. Activated charcoal is given orally and as it passes from one end to the other, toxins are trapped in the charcoal so that when the charcoal passes from the patient, the toxins pass, too. This technique of detoxification may be used in the treatment of marijuana toxicity if ingestion has occurred recently.
Fluid support and keeping the patient warm may also be needed in treatment. If the patient has lost consciousness, the more intense observation and support is needed. The chance of fatality is statistically small but possible. In most cases, the patient can simply be confined so as to prevent injury until the THC wears off.
Page last updated: 12/10/2012