Presented to the Hawaii State Department of Health’s Office of Medical Cannabis Control and Regulation — Clinical Curriculum by Dr. Benjamin Caplan.

Most people—including many practicing clinicians—assume they understand the “basics” of cannabis. However, the majority of information circulating in the public sphere is not science; it is recycled folklore, dispensary marketing lingo, and arbitrary dosing rules that leave both patients and healthcare providers guessing. When I was invited by the Hawaii State Department of Health to present to their regulatory and medical oversight teams, my goal was to offer something fundamentally different: a rigorous, accessible, and clinically unvarnished walk through how cannabinoids actually interact with the human body, why universal dosing formulas fail, and how modern medicine must evolve to utilize this therapeutic resource responsibly.

1. The Endocannabinoid System: The Body’s Master Homeostatic Regulator

To understand medical cannabis, one must first understand the biological infrastructure built to receive it. The human body does not possess cannabinoid receptors because of a plant; the plant happens to produce molecules that mimic our own internal chemistry.

• Retrograde Signaling: Unlike traditional neurotransmitters (such as serotonin or dopamine), which travel anterograde from the presynaptic to the postsynaptic neuron, endocannabinoids (primarily Anandamide and 2-Arachidonoylglycerol or 2-AG) travel backward. They are synthesized on demand in the postsynaptic cell and travel backward across the synapse to bind presynaptic CB1 receptors, acting as a molecular dimmer switch that prevents neural hyper-excitation.
• Receptor Distribution:
  • CB1 Receptors: Concentrated predominantly in the central nervous system (basal ganglia, hippocampus, cerebellum, cortex). Critically, CB1 receptors are virtually absent in the brainstem cardiorespiratory centers, which explains why cannabinoids do not cause fatal respiratory depression, unlike opioids.
  • CB2 Receptors: Located primarily on peripheral immune cells, B-cells, macrophages, and microglia, modulating systemic inflammation, pain transduction, and tissue healing.
  • Non-Cannabinoid Targets: Cannabinoids also interact with TRPV1 (vanilloid) pain receptors, 5-HT1A serotonin receptors, and PPAR nuclear receptors.

2. Why the Universal “5mg Starting Dose” Is a Dangerous Oversimplification

In retail cannabis culture, “5mg” is often touted as the universal starter dose. In clinical practice, this arbitrary figure is frequently either completely ineffective or profoundly overwhelming.

Cannabinoids exhibit a classic biphasic dose-response curve. A low dose of a cannabinoid may alleviate anxiety, stimulate appetite, and promote cognitive clarity, whereas a higher dose in the exact same individual can trigger acute panic, hyperemesis, sedation, and dysphoria. Furthermore, therapeutic response is dictated by factors far more complex than body weight:

• Endocannabinoid Tone: A patient with clinical endocannabinoid deficiency may experience profound relief at micro-doses (e.g., 1.0 to 2.0 mg of active cannabinoid), while someone with receptor downregulation from chronic exposure may require a customized tolerance protocol (such as our 48-Hour Tolerance Reset Protocol).
• Baseline Anxiety and Autonomic Tone: High sympathetic arousal amplifies the psychological sensitivity to CB1 receptor stimulation.
• Gut Microbiome and Meal Composition: Co-ingesting oral cannabinoids with high-fat meals dramatically enhances lymphatic absorption and systemic bioavailability by up to four-fold.

3. Why Edibles Feel Like an Entirely Different Drug: The 11-Hydroxy-THC Factor

When patients report that “edibles hit them like an entirely different substance,” they are describing an objective biochemical reality, not an exaggeration. When cannabis is inhaled or absorbed sublingually, delta-9-THC enters systemic circulation directly. However, when ingested orally, delta-9-THC is absorbed through the gut and delivered directly via the portal vein to the liver.

In the liver, the cytochrome P450 enzyme CYP2C9 oxidizes delta-9-THC into 11-hydroxy-THC. Pharmacological research demonstrates that 11-hydroxy-THC crosses the blood-brain barrier substantially faster, possesses a higher binding affinity at CB1 receptors, and produces subjective psychoactive effects estimated at two to three times more potent than delta-9-THC. When patients are unaware of this metabolic conversion or impatient during the delayed 90-minute onset, they frequently re-dose prematurely, leading to intense dysphoria and emergency department visits.

4. What Medical Schools Never Taught: Hepatic CYP450 Drug-Drug Interactions

Most physicians practicing today received zero hours of formal endocannabinoid education during their undergraduate medical training or residency. As a result, critical pharmacokinetic interactions are frequently overlooked:

1. CYP3A4 and CYP2C19 Inhibition: Cannabidiol (CBD) is a potent competitive inhibitor of hepatic CYP3A4 and CYP2C19. In patients taking pharmaceuticals metabolized by these pathways—such as macrolide antibiotics, selective serotonin reuptake inhibitors (SSRIs), calcium channel blockers, or statins—CBD can elevate serum drug levels, leading to unexpected clinical toxicity.
2. Anticonvulsant Interactions (Clobazam & Valproate): In pediatric and adult neurological care, combining high-dose CBD with clobazam causes a three- to five-fold accumulation of the active metabolite N-desmethylclobazam, inducing profound sedation unless prescription dosages are proactively tapered. Co-administration with valproate requires routine AST/ALT liver enzyme monitoring due to risk of transaminase elevations.
3. Blood Thinners (Warfarin): Both CBD and THC can inhibit CYP2C9, the primary enzyme responsible for metabolizing the more potent S-enantiomer of warfarin. Without physician oversight and frequent INR monitoring, patients risk dangerous elevations in anticoagulation and severe bleeding complications. Clinicians should consult our dedicated CED Clinic CYP450 Interaction Checker for baseline risk stratification.

5. Beyond Indica vs. Sativa: The Modern Chemovar Classification

The dispensary classification of cannabis into “Indica” (sedating) and “Sativa” (energizing) is a botanical taxonomy based on morphology and leaf shape that has zero correlation with modern chemical pharmacology. In clinical practice, we categorize cannabis into distinct chemovars:

• Type I (THC-Dominant): High THC (>15%), low CBD (<1%). Useful for severe refractory pain, muscle spasticity, and chemotherapy-induced nausea, but carries the highest risk of intoxication and anxiety.
• Type II (Balanced Ratio): Approximately 1:1, 2:1, or 1:2 CBD to THC. Often represents the clinical “sweet spot” for chronic musculoskeletal pain, anxiety, and neuropathic distress, where CBD mitigates the psychoactive side effects of THC while preserving therapeutic efficacy.
• Type III (CBD-Dominant): High CBD, low THC (<0.3% to 1%). Ideal for inflammatory conditions, daytime anxiety, pediatric seizures, and patients seeking therapeutic relief with zero cognitive impairment.
• Terpene Modulators: Aromatic terpenes like myrcene (sedating, muscle-relaxing), beta-caryophyllene (a dietary cannabinoid that directly activates CB2 receptors), and limonene (anxiolytic) fundamentally shape the clinical entourage effect.

Download the Full Hawaii Department of Health Lecture Slides

For clinicians, health policy leaders, and patients wishing to review the complete slide deck from this address, the original materials are accessible below:

Frequently Asked Questions: Clinical Cannabis Fundamentals

Written & Medically Reviewed by Benjamin Caplan, MD

ABFM Board-Certified Family Physician | MA Medical License #240562 | NPI: 1962722637
Founder & CMO of CED Clinic & CED Foundation | Author of The Doctor-Approved Cannabis Handbook

Dr. Benjamin Caplan has evaluated over 350,000 patients across his career, serving as a trusted clinical advisor to health departments, academic institutions, and healthtech innovators. For personalized consultations, explore CED Clinic or read his definitive text, The Doctor-Approved Cannabis Handbook.