Scientific evidence on therapeutic marihuana use in individuals treated in Health Care Services

Evidências científicas sobre o uso terapêutico da maconha para as pessoas que frequentam os serviços de saúde

The possibility of cannabis-based medications being used is viewed with mistrust and there are many doubts regarding therapeutic marihuana use. "Marihuana is a generic term used to refer to "Cannabis Sativa", an herbaceous plant with psychoactive properties. There are records of C. Sativa use dating back to 4,000 BC in China, where it was used to treat a range of afflictions"¹. "Cannabis Sativa has approximately 489 components, with more than 80 terpene phenolic compounds, known as cannabinoids. The others are components such as terpenes, hydrocarbons, ketones, aldehydes and other small hydrophobes able to cross the hematoencephalic barrier"¹.

In 1963 and 1964 the chemical structures of Delta-9-Tetrahydrocannabinol (Δ9-THC), the psychoactive component of Cannabis, and of Cannabidiol (CBD) were discovered, these being the principal components of Cannabis. "The Δ9-THC/CBD rate differs between strains. The proportion of Δ9-THC, and therefeore psychoactive strength, has increased over time from 1-5% in the 1960s to current levels of around 10-15%"¹.

In this context, cannabis "is of great interest for medicinal use for its anxiolytic, antiemetic, analgesic and anti-inflammatory properties"². "Different studies have discovered the therapeutic effects of canniboid treatments: in the 1980s, several authors conducted clinical trials to compare the effectiveness of THC with other antiemetic medications and placebos in treating nausea and vomiting from chemotherapy. These studies show that THC is at least as effective as conventional treatments with dopamine antagonists"².

"According to research published in the Journal of the American Medical Association (JAMA), there is moderate to high quality evidence of the compatibility of cannabis use for certain diseases, although not for others. After reviewing 80 random trials with around 6,500 individuals, the authors found moderate support for using cannabis to treat chronic pain and muscular spasms and involuntary movements" ⁽³. "In 1995, Beal J. et al designed a 6 week Controlled Clinical Trial to evaluate the effects of dronabinol (synthetic THC in an oral capsule) on increased appetite and weight gain in patients with Acquired Immune Deficiency Syndrome (AIDS)-associated anorexia. The results showed that dronabil is safe and effective in treating this"⁴. The cannabinoids studied included smoking marihuana, orally-administered cannabis extracts and cannabis-based medications such as Nabilona and Dronabinol.

Thus, in several countries, therapeutic use of marihuana is accepted to counteract the effects of certain pathologies. Given this context, this study was guided by the following question: What scientific evidence is there on the therapeutic use of marihuana in the sick treated in health care services? In order to answer this question, we undertook an integrative review of the literature, aiming to identify, synthesize and evaluate the scientific evidence available on therapeutic marihuana use in the sick treated in different health care services.

This was an integrative review, a "focus that enables different methodologies, for example experimental and non-experimental, to be combined, and which tends to produce a coherent, global view of complex concepts and theories of health problems". ("Whittemore; Knafl, 2005.)⁵. This review followed the six stages proposed by Ganon (1987)⁶.

The first stage is selecting the topic of interest. The PICo⁷ strategy was used when developing the question for the integrative review. P stands for the population or problem - describe the population in question, I stands for the phenomenon of Interest - describe what will be investigated in the study and Co stands for the context in which the phenomenon in question occurs. In this integrative review, PICo is as follows:

P: the sick

I : therapeutic marihuana use

Co: Health care services

Thus, the research question is: What scientific evidence is there on the therapeutic use of marihuana in the sick treated in health care services?

Inclusion criteria for the articles were as follows: primary articles, complete texts, from indexed journals, published in Spanish, English or Portuguese. Excluded articles were those which dealt with other types of drugs or those that referred to drugs in general.

The primary studies were selected from the LILACS (Latin American and Caribbean Health Sciences Literature), CINALH (Cumulative Index to Nursing and Allied Health Literature) and MEDLINE (MEDical Literature Analysis and Retrieval System On Line (MEDLINE) databases and the search was later widened with tools such as WOS (Web of Science) and SCOPUS⁸.

To review the primary studies that responded to the research question we used a combination of Boolean descriptors using the operators AND and OR, as follows:

1. - Marihuana OR "Marijuana Medicinal" OR "Cannabis sativa"

2. - Therapeutic use

3. - Health care services OR "Health care centers"

4. - To broaden the search we included controlled descriptors (DeCS) as follows:

5. - Marihuana Medicinal (DECS) OR Cannabis sativa (DECS)

6. - Health care centers (DECS) OR Hospitals (DECS)

The various stages of the search were reviewed by a librarian and the research question was the basis on which studies were selected for this integrative review. Table 1 shows a summary of the selection of the primary data in the databases.

Table 1
Summary of the selection of the primary data in the databases.

De noventa artículos localizados inicialmente en las diferentes bases de datos, solo seis resultaron seleccionados para esta revisión integrativa, eliminando los que no cumplían los criterios de inclusión.

The instrument validated by "Ursi (2005)"¹⁰ was authorized for use to extract information from the selected studies, for the following items: identification, objectives, methodological characteristics, res ults and conclusions.

As well as analyzing the selected articles, they were categorized, according to the criteria proposed by Stetler (1998)¹¹, hierarchized according to the classification of the evidence, depending on the methodological focus.

Comparisons and conclusions were then made of the studies included in the review, based on critical evaluation of the results as well as the implications of the review.

The data are presented below. All of the articles selected originated in medical research, allowing Nursing professionals to increase knowledge on the therapeutic Marihuana use that can lead to a discussion on the involvement of Nursing in therapeutic use of this product.

A search was conducted in the databases available for primary articles containing scientific evidence on therapeutic marihuana use published in Spanish, Portuguese or English. Ninety studies were found in the EBSCO, PUB-MED Mediline, CINHAL, SCOPUS; LILACS and WEB OF SCIENCE yielded no results. Of these ninety studies, fifty-three were primary studies, all in English. After translating and reading the titles, twenty-seven articles were found to be on the topic of the research: "Therapeutic marihuana in individuals treated in Health Care Services"; of these, five studies met the exclusion criteria and six were duplicated in other databases, leaving sixteen studies of which the abstracts were translated into Spanish, after which a further seven articles were eliminated. Nine articles were eventually translated in full, when it became evident that one article was not a primary study and another examined the side effects of marihuana use. A third examined the effects of Haloperidol in cyclical vomiting resulting from marihuana consumption. Eventually, six studies were selected and analyzed for this integrative review.

The figure below shows the stages of selecting the articles for this review.

Figure 1
Details of the selection of the primary studies located in the EBSCO, PUBMED, CINAHL and SCOPUS databases and included in the integrative review, Ribeirao Preto, March 2016.

Table 2
Distribution of the studies included in the integrative review, according to author, title, source, country of origin, year of publication, objectives and level of evidence.

Analysis of the six articles enabled us to extract three common categories: Need for careful dosing and monitoring when using cannabis for therapeutic purposes; Subjective beneficial effects or triggering adverse side effects and Limited evidence as to its efficacy.

This integrative review seeking scientific evidence on the therapeutic marihuana use by individuals in Health Care Services verified the limited availability of primary scientific articles on the subject, particularly in Spanish. At the same time, it found that there are no nursing publications on the therapeutic marihuana use. The most important findings relate to the existence of limited evidence on the efficacy of cannabis or the products beneficial effects, and this is mainly due to the placebo effect it produces. Adverse side effects that can be triggered by cannabis use mean there is a need for careful monitoring and ongoing evaluation when using cannabis for therapeutic purposes.

Quiero expresar mis agradecimiento a La Escuela de Enfermería de Ribeirão Preto de la Universidad de São Paulo (EERP-USP) y al Centro Colaborador de la OMS para el Desarrollo de la Investigación en Enfermería y la Secretaria Nacional de Políticas sobre Drogas - SENAD por la posibilidad de realizar este estudio e investigación en Alcohol y otras Drogas Psicoactivas. Agradezco a los organizadores por la acogida, el esmero y gentileza de la planificación en cada fase del curso, y por la confianza que depositaron en mi al aceptarme como parte del equipo de investigadores. Hago especial agradecimiento a mi tutora que con paciencia y cariño supo encaminarme y hacerme agradable esta experiencia.

Agradezco a la Escuela de Enfermería de la Universidad de Valparaíso, Chile, por las facilidades que me fueron otorgadas para hacer esta formación. Quiero también desearles gran armonía al equipo y éxito en los cursos venideros, es cansador el trabajo y talvez no veamos los resultados de inmediato, pero vale la vida trabajar por tener un mundo mejor.