卡痛（Kratom）：风险、药理机制及其与阿片类药物的关联
摘要
本期 Huberman Lab AMA 节目探讨了卡痛的短期与长期影响。卡痛是一种源自印度尼西亚的植物提取物，在人体内具有阿片类药物的作用机制。Huberman 详细解析了卡痛的药理特性、成瘾潜力，以及围绕将其用于戒断更强效阿片类药物这一争议性话题的各方观点。核心信息十分明确：卡痛并非一种无害的膳食补充剂，从未使用过的人应完全避免接触。
核心要点
- 卡痛是一种阿片类物质 —— 尽管通常有人声称并非如此，但它与吗啡和氢可酮一样，能与相同的 μ-阿片受体结合。
- 在低剂量下，卡痛产生轻微的兴奋效果；在较高剂量下，它成为一种具有显著成瘾潜力的镇痛药和镇静剂。
- 10–40% 的人对阿片类药物可能存在增强反应，使其尤其容易对卡痛产生依赖。
- 卡痛的效力约为氢可酮的六分之一，但使用者可以且确实会通过提高剂量来弥补这一差距。
- 一些人已成功利用卡痛逐渐戒断更强效的阿片类药物，但最终目标必须是同样戒断卡痛本身。
- 单独使用卡痛导致死亡的情况较为罕见，但与酒精或其他阿片类药物合用时，由于呼吸抑制作用，死亡风险会显著增加。
- 缺乏标准化监管意味着各品牌卡痛产品的生物碱浓度差异悬殊，不同品牌之间的剂量比较毫无意义。
- 如果你从未使用过卡痛，最安全的做法就是永远不要开始。
详细笔记
卡痛是什么？
- 提取自原产于印度尼西亚的树木Mitragyna speciosa（帽柱木）
- 已有数百年的使用历史，传统上以咀嚼叶片的方式服用
- 如今以胶囊或原粉形式在柜台出售 —— 在美国无需处方
- 含有多种植物alkaloids（生物碱），与endogenous opioid system（内源性阿片系统）的相互作用方式各不相同
剂量依赖性效应
- 低剂量（兴奋剂范围）： 轻度提神、轻度欣快感
- 较高剂量（阿片类药物范围）： 镇痛（止痛）、镇静、梦幻状态
- 常被引用的”安全”范围为每日 1–6 克，但由于各品牌生物碱浓度不同，这一数据并不可靠
药理机制：卡痛如何发挥作用
- 卡痛主要与μ-阿片受体结合（与其仅结合 κ-阿片受体的流行说法相悖）
- 在较小程度上也与κ-阿片受体结合
- 在服用卡痛前使用μ-阿片受体阻断剂后，所有效应——欣快感、镇痛、镇静，甚至轻微的兴奋效果——均被消除，从而证实了其阿片类药物作用机制
- 卡痛间接激活dopamine（多巴胺）和血清素强化回路，从而增强其成瘾潜力
- 涉及的关键脑区：脑干中的中脑导水管周围灰质，该区域负责调节疼痛缓解
内源性阿片系统
- 所有人体内都天然产生与阿片受体结合的endogenous opioids（内源性阿片物质）
- runner’s high（跑步者高峰体验）是一个现实例子：长时间重复性运动会触发内源性阿片物质的释放，产生轻度欣快感、镇痛效果和感知改变
- 卡痛、吗啡和氢可酮均能模拟这些天然化合物，但效力远高于后者
成瘾风险
- 卡痛符合成瘾性物质的定义：在产生负面后果的情况下持续使用，以及能带来愉悦感的事物范围逐渐缩小
- 估计10–40% 的人对阿片类药物会产生显著更强的欣快反应——这类人群面临最高的成瘾风险
- 与酒精的类比：约8–10% 的饮酒者对dopamine（多巴胺）会产生增强反应，使其患alcohol use disorder（酒精使用障碍）的风险升高
- 成瘾的一个关键指标：当想到即使停用 7–10 天时，也会产生焦虑或抗拒情绪
卡痛与阿片类药物危机
- 一些人已成功利用卡痛逐步戒断更强效的阿片类药物（吗啡、羟考酮/OxyContin、氢可酮）
- 医疗专业人员认可这种使用方式，但仅在使用者承诺逐步降低卡痛剂量并最终完全停用的前提下给予支持
- 替代陷阱的风险：使用者可能不断提高卡痛剂量，直至其效果与他们试图戒断的药物相近
呼吸风险与死亡
- 阿片类药物会抑制**physiological sigh**（生理性叹息）——一种在睡眠中自发产生的呼吸模式，负责重新充盈肺部并调节血氧/二氧化碳水平
- 睡眠中这一反射受到抑制，是阿片类药物相关死亡的主要机制
- 低至中等剂量的卡痛单独使用时，似乎不会显著抑制呼吸
- 然而，将卡痛与酒精或其他阿片类药物合用可能导致呼吸受到危险性抑制
- 已有归因于卡痛的死亡案例，很可能涉及多药物联合使用
监管问题
- 卡痛补充剂尚未标准化 —— 各品牌间生物碱浓度存在显著差异
- 某品牌的 1 克卡痛无法与另一品牌的 1 克进行有意义的比较
- 高度滥用潜力与极少的监管措施并存，构成重大的公共卫生隐患
相关概念
- kratom
- opioid addiction
- endogenous opioid system
- mu-opioid receptor
- kappa-opioid receptor
- dopamine
- serotonin
- runner’s high
- physiological sigh
- alcohol use disorder
- respiratory suppression
- addiction
- alkaloids
- drug tolerance
English Original 英文原文
Kratom: Risks, Pharmacology, and the Opioid Connection
Summary
This episode of the Huberman Lab AMA addresses the short and long-term effects of kratom, a plant-derived substance from Indonesia that acts as an opioid in the body. Huberman breaks down kratom’s pharmacology, its addictive potential, and the controversial debate around its use as a tool for weaning off more potent opioids. The core message is clear: kratom is not a benign supplement, and those who have never taken it should avoid it entirely.
Key Takeaways
- Kratom is an opioid — it binds to the same mu-opioid receptors as morphine and hydrocodone, despite common claims to the contrary.
- At low doses, kratom produces mild stimulant effects; at higher doses, it becomes an analgesic and sedative with significant addiction potential.
- 10–40% of people may have a heightened response to opioids, making them especially vulnerable to kratom addiction.
- Kratom is approximately one-sixth the potency of hydrocodone, but users can and do escalate dosages to compensate.
- Some people have successfully used kratom to taper off more potent opioids, but the goal must be to eventually come off kratom as well.
- Death from kratom alone is rare but becomes more likely when combined with alcohol or other opioids due to respiratory suppression.
- The lack of standardized regulation means kratom products vary wildly in alkaloid concentration, making dosage comparisons between brands unreliable.
- If you have never taken kratom, the safest course of action is to never start.
Detailed Notes
What Is Kratom?
- Derived from the tree Mitragyna speciosa, native to Indonesia
- Has been used for hundreds of years; traditionally consumed by chewing the leaves
- Today sold over the counter as capsules or raw powder — no prescription required in the United States
- Contains multiple plant alkaloids that interact differently with the endogenous opioid system
Dose-Dependent Effects
- Low dose (stimulant range): mild energy boost, mild euphoria
- Higher dose (opioid range): analgesia (pain relief), sedation, dreamlike states
- Commonly cited “safe” range: 1–6 grams per day, but this figure is unreliable due to variable alkaloid concentrations across brands
Pharmacology: How Kratom Works
- Kratom primarily binds to the mu-opioid receptor (contrary to the popular claim that it only binds kappa-opioid receptors)
- Also binds the kappa-opioid receptor to a lesser degree
- When a mu-opioid receptor blocker is administered before kratom, all effects — euphoria, analgesia, sedation, even the mild stimulant effect — are eliminated, confirming its opioid mechanism
- Kratom indirectly activates dopamine and serotonin reinforcement circuits, contributing to its addictive potential
- Key brain region involved: the periaqueductal gray nucleus in the brainstem, which mediates pain relief
The Endogenous Opioid System
- All humans naturally produce endogenous opioids that bind to opioid receptors
- The runner’s high is a real-world example: long-duration repetitive effort triggers release of endogenous opioids, producing mild euphoria, analgesia, and altered perception
- Kratom, morphine, and hydrocodone mimic these natural compounds but at much higher potency
Addiction Risk
- Kratom meets the definition of an addictive substance: continued use despite negative consequences, and the progressive narrowing of things that bring pleasure
- An estimated 10–40% of people respond to opioids with significantly greater euphoria — these individuals are at highest risk
- Parallel noted with alcohol: roughly 8–10% of alcohol users experience heightened dopamine responses, putting them at elevated risk for alcohol use disorder
- A key indicator of addiction: anxiety or resistance at the idea of stopping use for even 7–10 days
Kratom and the Opioid Crisis
- Some people have used kratom to successfully taper off more potent opioids (morphine, oxycodone/OxyContin, hydrocodone)
- Medical professionals acknowledge this use case but only support it if the person commits to progressively lowering kratom doses and eventually stopping entirely
- Risk of substitution trap: users may escalate kratom dosage until its effects closely resemble those of the drugs they were trying to quit
Respiratory Risk and Death
- Opioids suppress the physiological sigh — an involuntary breathing pattern during sleep that reinflates the lungs and regulates oxygen/CO₂ levels
- Suppression of this reflex during sleep is a primary mechanism behind opioid-related death
- Kratom at low to moderate doses does not appear to significantly suppress respiration on its own
- However, combining kratom with alcohol or other opioids can dangerously suppress respiration
- Deaths attributed to kratom have occurred, likely involving polydrug combinations
Regulation Concerns
- Kratom supplements are not standardized — alkaloid concentrations vary significantly between brands
- One gram of one brand cannot be meaningfully compared to one gram of another
- High abuse potential combined with minimal regulatory oversight is a significant public health concern
Mentioned Concepts
- kratom
- opioid addiction
- endogenous opioid system
- mu-opioid receptor
- kappa-opioid receptor
- dopamine
- serotonin
- runner’s high
- physiological sigh
- alcohol use disorder
- respiratory suppression
- addiction
- alkaloids
- drug tolerance