Cannabis Prohibition: Perspectives in Veterinary Medicine

1. Cannabis and Cannabidiol

Cultivated almost globally due to its easy adaptation, Cannabis sativa plants hold over one hundred identified compounds called cannabinoids. However, it is not the only species of the Cannabis genus. There are also Cannabis indica, a species with a low concentration of the psychoactive substance THC (tetrahydrocannabinol), and Cannabis ruderalis, with no psychoactive properties.1

Phytocannabinoid compounds are natural. They are plant-derived compounds. Endocannabinoids are also natural compounds, but these are not plant derived. Both act on the endocannabinoid system, producing physiological stimuli.2 Apart from THC, another essential cannabinoid extracted from cannabis is cannabidiol (CBD), which has no psychoactive effects. Both act on the endocannabinoid system; therefore, they have many pharmacological uses.3

Even though Cannabis sativa is a plant with well-known, long-recorded therapeutic effects, it is only now, with the recent discovery of cannabinoid receptors and the endocannabinoid system, that it is being prescribed more, mainly for pain treatment. The endocannabinoid system is complex and involves many pharmacological effects. Some of these effects are cannabinoid receptors CB1 and CB2, noncannabinoid receptors such as vanilloids (TRPV1) and serotonergic receptors (5-HT). Such complexity yields a large number of pharmacological effects.4

CBD acts in a myriad of ways.5 There are indications of its usefulness in the central nervous system as an analgesic, and also to control spasms, seizures, and anxiety; as an appetite stimulant; a bronchodilator; and as a treatment for glaucoma. It even acts on inflammatory responses, the immune system, and the thermoregulatory system.6

2. Interventionism: Prohibition

The first lawsuit to prohibit the sale and use of cannabis in the West took place in Brazil, in 1830, and was brought by the Rio de Janeiro town council.7 According to the council, at that time, several studies established effects such as aggressive behavior, delusions, and uncontrolled sexual impulses after its use. The lawsuit also classified users as compulsive drug addicts, placing marijuana in the opioid group. From 1934 on, they were penalized. But as Mark Thornton notes,

Interventionism, like the temperance organizations, was unable to establish total abstinence in society. After each failure, temperance groups would advocate more stringent policies.8

To Rothbard,9 prohibition is a sort of intervention he defined as “triangular intervention,” in which the state interferes in trades that people want to make among themselves. The state imposes or forbids the trade of goods and services among companies and consumers. Rothbard points out that triangular intervention can be divided into “price control” and “product control.”

Guilherme Resende Oliveira notes that

[m]ost illicit drug-associated deaths result from the illegal nature of the market (especially connected to violence and low quality) and not from the use in and of itself. For example, Cannabis does not kill by overdose, but the impurities in the “Paraguayan pressed weed” cause more significant damage to health than natural marijuana would. Before allocating further resources to fight the offer, the government should carefully evaluate the (evidence-based) consequences and tilt resources to the demand.10

In the 1950s, marijuana users started to be labeled as “potheads,” “troublemakers,” “thugs,” and “outlaws,” relating them to lower social classes. In the 1960s, with the “cultural revolution,” usage moved up to the middle class. These users became associated with a youth rebellion, which was always connected to criminalization. In this scenario, the use was not related to the plant’s psychopharmacological properties.

Drug prohibition has a negligible impact on demand across the board because it doesn’t interfere with the consumers’ choice. Thus, its result is an increase in price, which also indirectly raises crime rates since users might commit theft to maintain their vice or replace it with more dangerous substances.11

It is essential to point out that intervention via product control will alter price levels: the restriction of certain products will cause their scarcity and raise their prices. This scenario makes illegal activities financially viable.

3. Importance of Cannabinoids to Veterinary Medicine

There is still a scarcity of studies on the clinical use of cannabinoids in veterinary medicine once available data is limited to experimental findings in preclinical studies of human medicine. The development of research upon several species, not only laboratory guinea pigs, is necessary. Such reviews are essential to understand the effects of and adverse responses to cannabinoid substances.12

Animals are often diagnosed late with cancer, which makes tumor staging more difficult and contributes to an unfavorable diagnosis—the chances of metastasis and recurrence become higher, accompanied by pain.13 Pain during oncological treatment worsens prognoses and animals’ quality of life.14 Thus, oncological treatment for animals must be based on adopting effective analgesic protocols to ensure the quality of life and on prioritizing patients’ well-being.15

In veterinary medicine, opioids are the drugs of choice to treat pain in small animals, due to their easy availability, high efficacy, and the possibility of reversing their effects.16 However, studies with modified cannabinoids indicate that their analgesic potency is more elevated than that of morphine, for example, by two hundred to six thousand times.17 Besides, opioids are associated with adverse effects such as sedation, anorexia, nausea, and depression of the respiratory system.18

Also, in veterinary medicine, it is necessary to broaden research on the efficacy of cannabinoids. Still, authors like Carmela Valastro et al.19 report the use of synthetic agonists to treat dogs with joint disease.

Final Remarks

We miss chances to explore research opportunities to produce new medication scientifically. Many human-use medicines are first developed within veterinary medicine—animal research is an essential step in the medical research cycle.

Cannabinoid- and CBD-based medicines are already being commercialized for humane treatment. In veterinary medicine, available products are limited to phytocannabinoid-based treatments and are considered merely food supplements with no therapeutic purposes. This scenario happens because of the lack of studies, limiting practical applicability, as well as legal issues, and social stigma.20

Many veterinarians have oriented animal owners who have benefited from using cannabis-based medicines toward using them on their pets; however, this practice has no law to forbid, allow, or regulate its use.21 Depending on the state, they are considered outside the law.

• 1. Cristiane Ribeiro de Carvalho, Pedro Leite Costa Franco, Ingrid Eidt, Alexandre Ademar Hoeller, and Roger Walz, “Canabinoides e epilepsia: Potencial terapêutico do canabidiol.” Vittalle: Revista de ciências da Saúde 29, no. 1 (2017): 54–63, https://doi.org/10.14295/vittalle.v29i1.6292.
• 2. Marcos Adriano Lessa, Ismar Lima Cavalcanti, and Nubia Verçosa Figueiredo, “Derivados canabinóides e o tratamento farmacológico da dor,” Revista dor 17, no. 1 (January/March 2016): 47–51, https://doi.org/10.5935/1806-0013.20160012.
• 3. Alexandre Rafael de Mello Schier, Natalia Pinho de Oliveira RibeiroI, Adriana Cardoso de Oliveira e Silva, Jaime Eduardo Cecílio Hallak, José Alexandre S. Crippa, Antonio E. Nardi, and Antonio Waldo Zuardi, “Cannabidiol, a Cannabis sativa Constituent, as an Anxiolytic Drug,” Brazilian Journal of Psychiatry 34, no. 1 (2012): 104–10.
• 4. L. Landa, A. Sulcova, and P. Gbelec, “The Use of Cannabinoids in Animals and Therapeutic Implications for Veterinary Medicine: A Review,” Veterinarni Medicina 61, no. 3 (2016).
• 5. Schier, RibeiroI, Oliveira e Silva, Hallak, Crippa, Nardi, and Zuardi, “Cannabidiol, a Cannabis sativa Constituent, as an Anxiolytic Drug.”
• 6. Káthia Maria Honório, Agnaldo Arroio, and Albérico Borges Ferreira da Silva, “Aspectos terapêuticos de compostos da planta Cannabis sativa,” Química nova, 29, no. 2 (2006): 318–25.
• 7. Edward MacRae and Júlio Assis Simões. (2000). Rodas de fumo: O uso da maconha entre camadas médias. (Salvador, Brazil: Editora da Universidade Federal da Bahia, 2000), https://repositorio.ufba.br/ri/handle/ri/4702.
• 8. Mark Thornton, Economics of Prohibition (Auburn, AL: Ludwig von Mises Institute, 1991).
• 9. Murray N. Rothbard, Man, Economy, and State, with Power and Market, 2d scholar’s ed. (Auburn, AL: Ludwig von Mises Institute, 2009).
• 10. Guilherme Resende Oliveira, “Reflexões econômicas contra a proibição das Drogas,” MISES: Interdisciplinary Journal of Philosophy, Law and Economics 6, no. 3 (2018), https://doi.org/10.30800/mises.2018.v6.1103.
• 11. Ibidem.
• 12. Landa, Sulcova, Gbelec, “The Use of Cannabinoids in Animals and Therapeutic Implications for Veterinary Medicine: A Review.”
• 13. Thaís Rezende Mendes, Rafaela Peres Boaventura, Marielly Cunha Castro, and Maria Angélica Oliveira Mendonça, “Ocorrência da dor nos pacientes oncológicos em cuidado paliativo,” Acta Paulista de Enfermagem 27, no. 4 (August 2014): 356–61, https://doi.org/10.1590/1982-0194201400059.
• 14. Teresinha Luiza Martins, “Controle da dor e cuidados paliativos em cães e gatos com câncer. É possível? / Control of Pain and Palliative Care in Dogs and Cats with Cancer. Is It possible? / Control del dolor y cuidados paliativos en perros y gatos con cáncer. Es posible?,” Clínica Veterinária, 20, no. 115 (2015): 76–91.
• 15. Timothy M. Fan, “Pain Management in Veterinary Patients with Cancer,” Veterinary Clinics: Small Animal Practice, 44, no. 5 (2014): 989–1001.
• 16. B.T. Simon and P.V. Steagall, “The Present and Future of Opioid Analgesics in Small Animal Practice,” Journal of Veterinary Pharmacology and Therapeutics 40, no. 4 (2017): 315–26.
• 17. Honório, Arroio, Silva, “Aspectos terapêuticos de compostos da planta Cannabis sativa,” Química nova 29, no. 2 (2006): 318–25.
• 18. Jaseena Elikottil, Pankaj Gupta, and Kalpna Gupta, “The Analgesic Potential of Cannabinoids,” Journal of Opioid Management 5, no. 6 (2009): 341–57. Correction published in Journal of Opioid Management 6: 14.
• 19. Carmela Valastro, Debora Campanile, Mariarosaria Marinaro, Delia Franchini, Fabiana Piscitelli, Roberta Verde, Vincenzo Di Marzo, and Antonio Di Bello, “Characterization of Endocannabinoids and Related Acylethanolamides in the Synovial Fluid of Dogs with Osteoarthritis: A Pilot Study,” BMC Veterinary Research 13, no. 309 (2017): 1–5, https://link.springer.com/article/10.1186/s12917-017-1245-7.
• 20. Maíra Barrios Escobar, O potencial do canabidiol na terapêutica veterinária: Revisão de literatura (Boa Vista, Brazil, 2018), https://www.coursehero.com/file/59165137/O-Potencial-do-Canabidiol-na-Teraputica-Veterinria-Reviso-de-Literaturapdf/.
• 21. Caroline Apple, “No limbo da lei, veterinários prescrevem cannabis medicinal a animais doentes,” Sechat, Feb. 2, 2020, https://sechat.com.br/no-limbo-da-lei-veterinarios-prescrevem-cannabis-medicinal-a-animais-doentes/.