Expert advice for prescribing cannabis medicines for patients with epilepsy-drawn from the Australian clinical experience

Placental disposition of cannabidiol: An ex vivo perfusion study

OBJECTIVE

In the absence of safety data in humans, the use of cannabidiol (CBD) is not recommended during pregnancy. Yet >50% of pregnancies in women with epilepsy are unintended, making fetal exposure to CBD possible. As a small-molecule, highly lipid-soluble drug, CBD is likely to be distributed into the placenta and cross it. To estimate the placental distribution profile of CBD and its potential short-term placental effects, we conducted an ex vivo perfusion study in human placentas.

METHODS

Placentas were obtained from healthy women undergoing cesarean deliveries. Selected cotyledons were cannulated and perfused for 180 min with a CBD-containing medium (250 ng/mL, .796 μmol·L-1 ; representative of a low therapeutic concentration; n = 8). CBD concentrations were determined at 180 min in the medium and placental tissue using liquid chromatography-tandem mass spectrometry. A customized gene panel array was used to analyze the expression of selected genes in the perfused placental cotyledons as well as in placentas perfused with 1000 ng/mL CBD (3.18 μmol·L-1 ; high therapeutic concentration; n = 8) and in those exposed to the vehicle.

RESULTS

CBD was sequestered in the placental tissue, exhibiting significant variability across samples (median = 5342 ng/g tissue, range = 1066-9351 ng/g tissue). CBD concentrations in the fetal compartment were one fifth of those measured in the maternal compartment (median = 59 ng/mL, range = 48-72 ng/mL vs. 280 = ng/mL, range = 159-388 ng/mL, respectively; p < .01). Placental gene expression was not significantly altered by CBD.

SIGNIFICANCE

The placenta acts as a depot compartment for CBD, slowing down its distribution to the fetus. This phenomenon might yield flatter but prolonged fetal CBD levels in vivo. The attenuated transplacental CBD transfer does not imply that its use by pregnant women is safe for the fetus. Only pregnancy registries and neurocognitive assessments would establish the risk of being antenatally exposed to CBD.

History of Cannabis Regulation and Medicinal Therapeutics: It's Complicated

The genus Cannabis has a complex history, with great variations in the genus itself, as well as in its current uses worldwide. Today, it is the most commonly used psychoactive substance, with 209 million users in 2020. The legalization of cannabis for medicinal or adult use is complex. From its origins as a therapeutic agent in 2800 bc China, to the current knowledge on cannabinoids and the cannabinoid system, to the complex status of cannabis regulation across continents-knowledge gained from the history of cannabis use can inform research on cannabis-based treatments for patients with medical conditions that remain challenging in 21st century medicine, warranting research and evidence-based policy options. Changes in cannabis-related policymaking, scientific advances, and perceptions may result in increasing patient inquiries about its medicinal usage, regardless of personal opinions, thus meriting education and training of clinicians. This commentary outlines the long history of cannabis use, its current therapeutic potential from a regulatory research perspective, and the continued challenges in research and regulation in the ever-changing era of modern cannabis use. It is crucial to understand the history and complexity of cannabis use as medicine to better understand its potential for clinical therapeutics and the effects of modern-day legalization on other health- and society-related issues.

Medicinal Cannabis Guidance and Resources for Health Professionals to Inform Clinical Decision Making

PURPOSE

Interest in the use of cannabis as a medicine has markedly increased during the last decade, with an unprecedented number of patients now seeking advice or prescriptions for medicinal cannabis. Unlike other medicines prescribed by physicians, many medicinal cannabis products have not undergone standard clinical trial development required by regulatory authorities. Different formulations with varying strengths and ratios of tetrahydrocannabinol and cannabidiol are available, and this diversity of medicinal cannabis products available for a myriad of therapeutic indications adds to the complexity. Physicians face challenges and barriers in their clinical decision making with medicinal cannabis because of current evidence limitations. Research efforts to address evidence limitations are ongoing; in the interim, educational resources and clinical guidance are being developed to address the gap in clinical information and support the needs of health professionals.

METHODS

This article provides an overview of various resources that health professionals may use when seeking information about medicinal cannabis in the absence of high-quality evidence and clinical guidelines. It also identifies examples of international evidence-based resources that support clinical decision making with medicinal cannabis.

FINDINGS

Similarities and differences between international examples of guidance and guideline documents are identified and summarized.

IMPLICATIONS

Guidance can help guide physicians in the individualized choice and dose of medicinal cannabis. Before quality clinical trials and regulator-approved products with risk management programs, safety data require clinical and academic collaborative pharmacovigilance.

The Impact of P-Glycoprotein on Opioid Analgesics: What's the Real Meaning in Pain Management and Palliative Care?

Opioids are widely used in cancer and non-cancer pain management. However, many transporters at the blood-brain barrier (BBB), such as P-glycoprotein (P-gp, ABCB1/MDR1), may impair their delivery to the brain, thus leading to opioid tolerance. Nonetheless, opioids may regulate P-gp expression, thus altering the transport of other compounds, namely chemotherapeutic agents, resulting in pharmacoresistance. Other kinds of painkillers (e.g., acetaminophen, dexamethasone) and adjuvant drugs used for neuropathic pain may act as P-gp substrates and modulate its expression, thus making pain management challenging. Inflammatory conditions are also believed to upregulate P-gp. The role of P-gp in drug-drug interactions is currently under investigation, since many P-gp substrates may also act as substrates for the cytochrome P450 enzymes, which metabolize a wide range of xenobiotics and endobiotics. Genetic variability of the ABCB1/MDR1 gene may be accountable for inter-individual variation in opioid-induced analgesia. P-gp also plays a role in the management of opioid-induced adverse effects, such as constipation. Peripherally acting mu-opioid receptors antagonists (PAMORAs), such as naloxegol and naldemedine, are substrates of P-gp, which prevent their penetration in the central nervous system. In our review, we explore the interactions between P-gp and opioidergic drugs, with their implications in clinical practice.

Complementary and alternative therapies in the palliative setting

Complementary and alternative medicine (CAM) encompasses a wide range of medication, herbal, dietary and physical therapies that are not usually considered within the realm of conventional therapeutics. Approximately two thirds of the Australian population use CAMs and only around half of this number will discuss their use of these products with their doctor. Clinical use is commonly seen in patients with life-limiting illness, often because they experience a high burden of symptoms. However, it is also the case that many of these therapies do not have demonstrated efficacy, particularly for the often broad list of conditions and symptoms for which they are chosen to be used. Further, depending on whether they are sold as medications, sold as food supplements or imported illegally and distributed via nonstandard therapeutic channels, several products have had reports of toxicity, severe adverse effects, batch irregularities and drug interactions with other therapies. This awareness, together with lack of standardisation of products and lack of interchangeability between brands has made prescribers unwilling to put patients at risk of harm by supporting their use. In this article, we cover general pharmacological principles around use of a small selection of chemicals used in a medical setting to enable some guidance for use.

Unexpected short- and long-term effects of chronic adolescent HU-210 exposure on emotional behavior

Chronic adolescent cannabinoid receptor agonist exposure has been shown to lead to persistent increases in depressive-like behaviors. This has been a key obstacle to the development of cannabinoid-based therapeutics. However, most of the published work has been performed with only three compounds, namely Δ9-tetrahydrocannabinol, CP55,940 and WIN55,212-2. Hypothesizing that different compounds may lead to distinct outcomes, we herein used the highly potent CB₁R/CB₂R full agonist HU-210, and first aimed at replicating cannabinoid-induced long-lasting effects, by exposing adolescent female Sprague-Dawley rats to increasing doses of HU-210, for 11 days and testing them at adulthood, after a 30-day drug washout. Surprisingly, HU-210 did not significantly impact adult anxious- or depressive-like behaviors. We then tested whether chronic adolescent HU-210 treatment resulted in short-term (24h) alterations in depressive-like behavior. Remarkably, HU-210 treatment simultaneously induced marked antidepressant- and prodepressant-like responses, in the modified forced swim (mFST) and sucrose preference tests (SPT), respectively. Hypothesizing that mFST results were a misleading artifact of HU-210-induced behavioral hyperreactivity to stress, we assessed plasmatic noradrenaline and corticosterone levels, under basal conditions and following an acute swim-stress episode. Notably, we found that while HU-210 did not alter basal noradrenaline or corticosterone levels, it greatly augmented the stress-induced increase in both. Our results show that, contrary to previously studied cannabinoid receptor agonists, HU-210 does not induce persisting depressive-like alterations, despite inducing marked short-term increases in stress-induced reactivity. By showing that not all cannabinoid receptor agonists may induce long-term negative effects, these results hold significant relevance for the development of cannabinoid-based therapeutics.