Cannabis-based medicines and the perioperative physician.

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“Cannabis use for medicinal purposes was first documented in 2900 BC in China, when Emperor Shen Nong described benefit for rheumatism and malaria and later in Ancient Egyptian texts.

Discussion in medical journals, the mainstream and social media around the use of cannabis for medicinal and non-medicinal purposes has increased recently, especially following the legalisation of cannabis for recreational use in Canada and the UK government’s decision to make cannabis-based medicines (CBMs) available for prescription by doctors on the specialist register.

The actual, social and economic legitimisation of cannabis and its medicinal derivatives makes it likely increasing numbers of patients will present on this class of medicines. Perioperative physicians will require a sound understanding of their pharmacology and evidence base, and may wish to exploit this group of compounds for therapeutic purposes in the perioperative period.

The increasing availability of cannabis for both recreational and medicinal purposes means that anaesthetists will encounter an increasing number of patients taking cannabis-based medications. The existing evidence base is conflicted and incomplete regarding the indications, interactions and long-term effects of these substances.

Globally, most doctors have had little education regarding the pharmacology of cannabis-based medicines, despite the endocannabinoid system being one of the most widespread in the human body.

Much is unknown, and much is to be decided, including clarifying definitions and nomenclature, and therapeutic indications and dosing. Anaesthetists, Intensivists, Pain and Perioperative physicians will want to contribute to this evidence base and attempt to harness such therapeutic benefits in terms of pain relief and opiate-avoidance, anti-emesis and seizure control.

We present a summary of the pharmacology of cannabis-based medicines including anaesthetic interactions and implications, to assist colleagues encountering these medicines in clinical practice.”

https://www.ncbi.nlm.nih.gov/pubmed/31827774

“In summary, cannabinoids may improve pain relief as part of multi-modal approach. As the evidence base increases, CBMs could become part of the perioperative teams’ armamentarium to help provide an opiate sparing multimodal analgesia regime as well as having a role in the management of common post-operative complications such as nausea and vomiting.”

 https://perioperativemedicinejournal.biomedcentral.com/articles/10.1186/s13741-019-0127-x
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Δ9-THC and related cannabinoids suppress substance P- induced neurokinin NK1-receptor-mediated vomiting via activation of cannabinoid CB1 receptor.

European Journal of Pharmacology

“Δ9-THC suppresses cisplatin-induced vomiting through activation of cannabinoid CB1 receptors.

Cisplatin-evoked emesis is predominantly due to release of serotonin and substance P (SP) in the gut and the brainstem which subsequently stimulate their corresponding 5-HT3-and neurokinin NK1-receptors to induce vomiting. Δ9-THC can inhibit vomiting caused either by the serotonin precursor 5-HTP, or the 5-HT3 receptor selective agonist, 2-methyserotonin.

In the current study, we explored whether Δ9-THC and related CB1/CB2 receptor agonists (WIN55,212-2 and CP55,940) inhibit vomiting evoked by SP (50 mg/kg, i.p.) or the NK1 receptor selective agonist GR73632 (5 mg/kg, i.p.). Behavioral methods were employed to determine the antiemetic efficacy of cannabinoids in least shrews.

Our results showed that administration of varying doses of Δ9-THC (i.p. or s.c.), WIN55,212-2 (i.p.), or CP55,940 (i.p.) caused significant suppression of SP-evoked vomiting in a dose-dependent manner. When tested against GR73632, Δ9-THC also dose-dependently reduced the evoked emesis.

The antiemetic effect of Δ9-THC against SP-induced vomiting was prevented by low non-emetic doses of the CB1 receptor inverse-agonist/antagonist SR141716A (<10 mg/kg). We also found that the NK1 receptor antagonist netupitant can significantly suppress vomiting caused by a large emetic dose of SR141716A (20 mg/kg).

In sum, Δ9-THC and related cannabinoids suppress vomiting evoked by the nonselective (SP) and selective (GR73632) neurokinin NK1 receptor agonists via stimulation of cannabinoid CB1 receptors.”

https://www.ncbi.nlm.nih.gov/pubmed/31738934

https://www.sciencedirect.com/science/article/pii/S0014299919307587?via%3Dihub

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Perception of Benefits and Harms of Medical Cannabis among Seriously Ill Patients in an Outpatient Palliative Care Practice.

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“Patients with serious illness often have pain, uncontrolled symptoms, and poor quality of life. Evidence continues to evolve regarding the role of cannabis to treat chronic pain, nausea, and anorexia. Little is known about how patients with serious illness perceive its benefits and harms. Given that an increasing number of clinicians across the United States are treating patients with medical cannabis, it is important for providers to understand patient beliefs about this modality. We assessed patient perceptions of benefits and harms of cannabis who obtained a medical cannabis card within an ambulatory palliative care (APC) practice.

Results: All 101 patients invited to participate completed the survey. A majority had cancer (76%) and were married (61%), disabled or retired (75%), older than 50 years of age (64%), and men (56%). Most patients ingested (61%) or vaporized (49%) cannabis products. A majority of respondents perceived cannabis to be important for their pain (96%) management. They reported that side effects were minimally bothersome, and drowsiness was the most commonly reported bothersome harm (28%). A minority of patients reported cannabis withdrawal symptoms (19%) and concerns for dependency (14%). The majority of patients were using concurrent prescription opioids (65%). Furthermore, a majority of cancer patients reported cannabis as being important for cancer cure (59%).

Conclusion: Patients living with serious illnesses who use cannabis in the context of a multidisciplinary APC practice use cannabis for curative intent and for pain and symptom control. Patients reported improved pain, other symptoms, and a sense of well-being with few reported harms.”

https://www.ncbi.nlm.nih.gov/pubmed/31539298

https://www.liebertpub.com/doi/10.1089/jpm.2019.0211

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[Medicinal cannabis].

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“The use of cannabis products for medical purposes is rapidly increasing in the Netherlands. Studies suggest that these products have positive effects in the treatment of chronic neuropathic pain, multiple-sclerosis-related spasticity, certain epilepsy syndromes and chemotherapy-related nausea and vomiting.”

https://www.ncbi.nlm.nih.gov/pubmed/31120212

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Cannabinoids: the lows and the highs of chemotherapy-induced nausea and vomiting.

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“Despite remaining one of the most widely abused drugs worldwide, Cannabis sativa exhibits remarkable medicinal properties. The phytocannabinoids, cannabidiol and Δ-9-tetrahydrocannabinol, reduce nausea and vomiting, particularly during chemotherapy. This is attributed to their ability to reduce the release of serotonin from enterochromaffin cells in the small intestine, which would otherwise orchestrate the vomiting reflex. Although there are many preclinical and clinical studies on the effects of Δ-9-tetrahydrocannabinol during nausea and vomiting, little is known about the role that cannabidiol plays in this scenario. Since cannabidiol does not induce psychotropic effects, in contrast to other cannabinoids, its use as an anti-emetic is of great interest. This review aims to summarize the available literature on cannabinoid use, with a specific focus on the nonpsychotropic drug cannabidiol, as well as the roles that cannabinoids play in preventing several other adverse side effects of chemotherapy including organ toxicity, pain and loss of appetite.”

https://www.ncbi.nlm.nih.gov/pubmed/30720344

https://www.futuremedicine.com/doi/10.2217/fon-2018-0530

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Dark Classics in Chemical Neuroscience: Δ9-Tetrahydrocannabinol.

 ACS Chemical Neuroscience

“Cannabis (Cannabis sativa) is the most widely used illicit drug in the world, with an estimated 192 million users globally.

The main psychoactive component of cannabis is (-)-trans-Δ9-tetrahydrocannabinol (Δ9-THC), a molecule with a diverse range of pharmacological actions. The unique and distinctive intoxication caused by Δ9-THC primarily reflects partial agonist action at central cannabinoid type 1 (CB1) receptors.

Δ9-THC is an approved therapeutic treatment for a range of conditions, including chronic pain, chemotherapy-induced nausea and vomiting, and is being investigated in indications such as anorexia nervosa, agitation in dementia, and Tourette’s syndrome.

It is available as a regulated pharmaceutical in products such as Marinol®, Sativex®, and Namisol®, as well as in an ever-increasing range of unregistered medicinal and recreational cannabis products.

While cannabis is an ancient medicament, contemporary use is embroiled in legal, scientific, and social controversy, much of which relates to the potential hazards and benefits of Δ9-THC itself.

Robust contemporary debate surrounds the therapeutic value of Δ9-THC in different diseases, its capacity to produce psychosis and cognitive impairment, and the addictive and “gateway” potential of the drug.

This review will provide a profile of the chemistry, pharmacology, toxicology, and recreational and therapeutic uses of Δ9-THC, as well as the historical and societal importance of this unique, distinctive, and ubiquitous psychoactive substance.”

https://www.ncbi.nlm.nih.gov/pubmed/30689342

https://pubs.acs.org/doi/10.1021/acschemneuro.8b00651

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Prospects for the Use of Cannabinoids in Oncology and Palliative Care Practice: A Review of the Evidence.

 cancers-logo“There is an increased interest in the use of cannabinoids in the treatment of symptoms in cancer and palliative care patients. Their multimodal action, in spite of limited efficacy, may make them an attractive alternative, particularly in patients with multiple concomitant symptoms of mild and moderate intensity. There is evidence to indicate cannabis in the treatment of pain, spasticity, seizures, sleep disorders, nausea and vomiting, and Tourette syndrome. Although the effectiveness of cannabinoids is limited, it was confirmed in neuropathic pain management and combination with opioids. A relatively favorable adverse effects profile, including no depressive effect on the respiratory system, may make cannabis complement a rather narrow armamentarium that is in the disposition of a palliative care professional.”

https://www.ncbi.nlm.nih.gov/pubmed/30678303

https://www.mdpi.com/2072-6694/11/2/129

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Cannabis and Turmeric as Complementary Treatments for IBD and Other Digestive Diseases.

 “Complementary therapies for inflammatory bowel disease (IBD) have earned growing interest from patients and investigators alike, with a dynamic landscape of research in this area. In this article, we review results of the most recent studies evaluating the role of cannabis and turmeric for the treatment of IBD and other intestinal illnesses.

RECENT FINDINGS:

Cannabinoids are well-established modulators of gut motility and visceral pain and have demonstrated anti-inflammatory properties. Clinical trials suggest that there may be a therapeutic role for cannabinoid therapy in the treatment of IBD, irritable bowel syndrome (IBS), nausea and vomiting, and GI motility disorders. Recent reports of serious adverse effects from synthetic cannabinoids highlight the need for additional investigation of cannabinoids to establish their efficacy and safety. Turmeric trials have demonstrated some promise as adjuvant treatment for IBD, though not in other GI disease processes. Evidence suggests that the use of cannabis and turmeric is potentially beneficial in IBD and IBS; however, neither has been compared to standard therapy in IBD, and thus should not be recommended as alternative treatment for IBD. For cannabis in particular, additional investigation regarding appropriate dosing and timing, given known adverse effects of its chronic use, and careful monitoring of potential bleeding complications with synthetic cannabinoids are imperative.”

https://www.ncbi.nlm.nih.gov/pubmed/30635796

https://link.springer.com/article/10.1007%2Fs11894-019-0670-0

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Practical Perspectives in the Treatment of Nausea and Vomiting.

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“Nausea and vomiting result from complex interactions between afferent and efferent pathways of the gastrointestinal tract, central nervous system, and autonomic nervous system. Afferent pathways from the vagus nerve, vestibular system, and chemoreceptor trigger zone project to nucleus tractus solitarius, which in turn relays signals to the central pattern generator to initiate multiple downstream pathways resulting in symptoms of nausea and vomiting. There is increasing evidence that the central pathway of chronic nausea is different from that of acute nausea and vomiting-and closely resembles that of neuropathic pain. This improved understanding of chronic nausea has resulted in a paradigm shift with regard to management strategy. Although conventional therapies such as antiemetics and prokinetics are commonly used to manage acute nausea and vomiting, they are historically not as effective in treating chronic nausea. Recently, neuromodulator agents, such as tricyclic antidepressants, gabapentin, olanzapine, mirtazapine, and benzodiazepines, and cannabinoids have been shown to be efficacious in the treatment of nausea and vomiting, and may be useful in the treatment of chronic symptoms. There is a need to study these agents, especially in the management of chronic functional nausea. Improved understanding of the central and peripheral circuitry of nausea and vomiting symptoms will allow for enhanced utilization of the currently available medications, and the development of novel therapeutic options.”

https://www.ncbi.nlm.nih.gov/pubmed/30614944

https://insights.ovid.com/crossref?an=00004836-900000000-97784

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Cannaboinoid Antiemetic Therapy.

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“There are currently three cannabinoids available on the pharmaceutical market.  Dronabinol and Nabilone are both synthetic tetrahydrocannabinol (THC) which the FDA has approved for treatment of chemotherapy-induced nausea and vomiting (CINV) after the failure of a trial of first-line anti-emetics.  Both are also FDA approved to treat anorexia associated with AIDS.  Recently, the FDA has also approved a cannabidiol (CBD) product to treat seizures associated with Lennox-Gastaut Syndrome and Dravel Syndrome in pediatric patients. However, there is no FDA approved indication for its use as an anti-emetic.  Independently produced cannabidiol extracts are being used increasingly in the general population for many non-FDA approved indications, frequently including nausea and emesis.  In states that have decriminalized marijuana, both in recreational and medicinal contexts, products with varying ratios of cannabidiol and THC are also used for their anti-emetic properties.”

https://www.ncbi.nlm.nih.gov/pubmed/30571051

https://www.ncbi.nlm.nih.gov/books/NBK535430/

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