Bhang or Indian hemp (Cannabis sativa) Toxicity in Livestock
Marijuana plant (Cannabis sativa/Cannabis indica, hemp; Ganja, Charas or Bhang in Hindi) poisoning in pets and livestock.
Cannabis (Bhang in Hindi) is a genus of dioecious (i.e. male and female plants are separate) flowering plants whose leaves are like that of human palm and divided into 3-7 toothed (serrated) leaflets. There are 3 species of the genus Cannabis viz. Cannabis sativa, Cannabis indica, and Cannabis ruderalis (a species with low THC contents and native to Central, Eastern Europe and Russia). Some authorities consider the two later named species as subspecies of Cannabis sativa. Cannabis sativa is a tall, skinny herb with light green leaves while Cannabis indica is a bushy herb with broad, dark green leaves. Cannabis sativa contains more THC and has a stimulating effect whereas Cannabis indica has a sedative, analgesic, relaxing and appetite stimulating effects because of its higher CBD contents. Cannabis indica can be found as a wildly growing weed in many parts of India particularly in Punjab,UP, and MP,Bihar. There are two main cultivars of cannabis:
a) Industrial cannabis (hemp): This type of cannabis has THC contents generally less than 0.3% but high CBD contents. It is cultivated to produce external fibers from its stem. This fiber is utilized in textile and paper industry to produce cloths, paper, ropes insulation material etc. The seeds are used in human and animal nutrition (e.g. cage bird feeding) and are known to be very rich in arginine, glutamic acid, sulphur containing amino acids (methionine and cystine), essential fatty acids (linoleic acid and α-linoleic acid) and protein contents (Rocca and Salvo, 2020).
b) Medicinal or recreational cannabis: This cultivar has high THC and CBD contents and is utilized for the production of marijuana, ganga, hashish and other cannabis products possessing a psychoactive effect. Chemical compounds (cannabinoids) derived from medicinal cannabis are used to treat a wide variety of human and animal disease conditions e.g. pain caused by spasticity in multiple sclerosis, rheumatic pain, migraine, osteoarthritis, anorexia, nausea and vomiting due to certain diseases and chemotherapy, neuropathic pain, glaucoma, epilepsy, fibromyalgia, certain types of cancer, Parkinson disease and brain tumors etc. (Russo, 2018; Rocca and Salvo, 2020).
Hindu Kush marijuana is a strain of Cannabis indica native to Hindu Kush Range of mountain on the border between Pakistan and Afghanistan. Owing to very high THC but very low CBD content, it is one of the best strains of marijuana for smoking. It made its way to USA in 1960s.
Prompted by prospects of export and removal of cannabis by UNO from the Schedule IV of the Single Convention on Narcotic Drugs (where cannabis was listed among the highly dangerous, addictive substances like heroin), The Federal Government of India approved the legalized production of cannabis with certain conditions. The use of cannabis is not completely banned in the country as its medical and scientific use is allowed under the law, Now, the farmers can grow it after obtaining a license from the government. The cultivation, sale, possession, processing and recreational use of medicinal cannabis without license are still illegal and punishable by the law. Decriminalization of cultivation of bhang is likely to increase the incidents of bhang poisoning in animals.
Medicinal cannabis is consumed in several illicit forms. Bhang is a traditional local drink prepared from the leaves and mature fruits of medicinal cannabis. It is much weaker than other products of cannabis. Charas is produced by rubbing the leaves, flowers, young twigs (shoots) and fruits of cannabis. Hashish is a solid or semisolid preparation produced by compressing the stalked resin glands (trichomes) of the cannabis.
Ganja is a product of cannabis derived from the resinous exudate of female flowers tops and unfertilized female flowers. Marijuana is a mixture of stems, leaves, flowers and seeds of cannabis. It is usually smoked as a cigarette.
Cannabis contains more than 400 chemical compounds which include more than 60 cannabinoids (aryl substituted meroterpenes). Delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the two most potent cannabinoids in cannabis. THC is the major psychoactive cannabinoid in cannabis and is highly lipid soluble. CBD lacks a psychoactive effect (Ashton, 2018) i.e. it is non-intoxicating. Rather, it counters the psychoactive action of THC.
Dogs and cats may accidently ingest toxic doses of marijuana (about 3 grams for a dog weighing about 14 kg) if the owner is used to recreational use of this illicit drug and has stored it in the home within the reach of the pets (Donaldson, 2002; Fitzgerald, 2013). Herbivorous animals avoid eating Cannabis plants when other palatable plants are available. Lack of availability of proper feed may oblige the hungry cattle to eat the marijuana plant (Driemeier, 1997). Equines and ruminants may also be exposed to bhang toxicity by grazing wildly growing green Cannabis plant (Cardassis, 1951; Driemeier, 1997). Cannabis (about 250 grams of dried bhang) is sometimes administered to fractious horses to control the vice of biting and overdosing may lead to toxicity. Clinical signs usually appear 30-60 minutes after exposure to marijuana. The severity of the signs varies depending upon the quantity ingested and the size of the animal. Signs are more or less similar in all domestic species and include depression, incoordination of gait during walking, dilatation of pupils (mydriasis), decrease in pulse and respiration rates, lethargy, excessive salivation, vomiting in dogs and cats, hypothermia, seizures, tremors, dribbling of urine, coma and occasionally death (Driemeier, 1997; Young, 2019). Some dogs may show hyperesthesia rather than depression. Equines may also show marked dyspnea, weakness of muscles and discharge of froth from the mouth (Cardassis, 1951).
Death due to cannabis toxicity is uncommon. Necropsy findings (congestion of G.I., respiratory and urinary tracts together with hemorrhages on heart and in the stomach) are non-specific (Driemeier, 1997). Diagnosis is based on: (1) the presence of cannabis plant in the grazing area, (2) history of exposure to cannabis plant or its products, (3) clinical signs – dribbling of urine (urinary incontinence) occurs in dogs affected with marijuana toxicity but not in other diseases with similar clinical manifestations and may serve as a clue for exposure to marijuana toxicity, (4) lab determination of cannabinoid metabolites in the urine samples and in the stomach contents. Differential diagnosis requires consideration of toxicity due to ivermectin, opioids, benzodiazepines (e.g. Valium®), ethyl alcohol, ethylene glycol, xylazine , and phenothiazine .
Rx
a) Inject metoclopramide @ 0.2-0.4 mg/kg b.wt. IM every 6-8 hours for 3 days to control vomiting (in dogs and cats only).
b) Administer warm Ringer’s solution IV @ 40-60 ml /kg b.wt. Add 5-10 ml of vitamin B complex.; contains betaine glucuronate, diethanolamine, glucuronate and nicotinamide) to this solution.
c) Using an orogastric or nasogastric tube (used in human infants) orally administer a slurry made from activated charcoal (@ 4 grams/kg b.wt. plus sodium sulphate @ 1-2 grams/kg b.wt.) to help reduce the absorption and enterohepatic recirculation of cannabis cannabinoids present in the stomach contents.
d) Keep the affected animal in a warm place to counter hypothermia. Cover the body of the large animal with a blanket.
e) If the animal is severely depressed, inject romazicon or flumazenil which is a selective GABAA receptors antagonist used to treat overdosing with benzodiazepines and to help reverse anesthesia). Give one injection slowly IV. If there is no effect, give the 2nd injection. Up to 5 injections can be given one after another till the affected animal is alert.
f) Inject diazepam @ 0.25-0.5 mg/kg b.wt. (IV only if the dog is agitated;
g) To counter circulatory collapse and depressions give IM injection of camphorated oil (prepared by dissolving 20 grams of camphor in 80 ml of olive oil) @15 to 30 ml in horses and cattle; 1-3 ml for dog, goat and sheep. Injection camphorated oil is a lifesaving cardiac and respiratory stimulant (Udall, 1954).
Notes:
1) Treatment of bhang toxicity is symptomatic and supportive.
2) In most cases, bhang toxicity is not life-threatening.
3) Do not decontaminate G.I tract if depression is very severe, otherwise aspiration pneumonia may occur.
4) N-acetylcysteine can be tried in the treatment of bhang toxicity because it is a general detoxicant. Two to 3 sachets BID per os would be sufficient for an adult dog/sheep/goat.
5) Camphorated oil is a cardiac and respiratory stimulant that can be used in the treatment of such disease conditions of animals as septicemia, pneumonia, collapse or shock, threatened heart failure, hypothermia due to sudden exposure to cold/rain cannabis poisoning etc. Weakness due to severe gastroenteritis can be combated with intramuscular injection of 30-60 ml of camphorated oil into the pectoral muscle (Udall, 1954). Camphorated oil for intramuscular injection can be prepared as follows:
Camphor (finely ground) = 20 grams
Olive oil (autoclaved) = 80 ml
Cotton seed oil may be substituted for olive oil in this prescription. To make a preparation that will not be cloudy when cold, set the oil in refrigerator for 2 to 3 days and then filter while cold. Ether may be added in proportion of 2 parts for each part of camphor for making the preparation more effective .
Compiled & Shared by- Team, LITD (Livestock Institute of Training & Development)
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