Kratom to Opioid Conversion: No Established Guidelines Exist
There are no validated clinical guidelines or equianalgesic conversion ratios for converting between kratom and pharmaceutical opioids, and such conversions should not be attempted in clinical practice.
Why Kratom Conversions Are Not Feasible
Lack of Standardization and Pharmacologic Uncertainty
- Kratom products contain over 40 alkaloids with highly variable concentrations, making dose standardization impossible 1
- The two main active compounds—mitragynine and 7-hydroxymitragynine—act as atypical opioid receptor agonists affecting mu, delta, and kappa receptors, but also modulate adrenergic, serotonergic, and dopaminergic pathways, creating unpredictable pharmacologic effects 1
- Animal studies suggest kratom alkaloids may be more potent than morphine, but no human equianalgesic data exist 2
- There is no quality control or FDA regulation of kratom products sold as dietary supplements, meaning actual alkaloid content varies wildly between products and even batches 3
Clinical Risks of Attempting Conversion
- Kratom has been associated with severe adverse effects including hepatotoxicity, seizures, hallucinations, respiratory depression, and death—often in the context of polysubstance use 2, 4
- Kratom inhibits CYP2D6, CYP3A, and P-glycoprotein, which can precipitate dangerous drug interactions when combined with pharmaceutical opioids 5
- Deaths involving kratom typically occur with co-ingestion of other substances, suggesting additive or synergistic toxicity 5
The Established Approach: Standard Opioid Conversions Only
When Patients Present on Kratom
If a patient reports using kratom for pain or opioid withdrawal and requires transition to pharmaceutical opioids:
- Do not attempt to calculate an equivalent opioid dose based on kratom use 2, 4
- Treat the patient as opioid-naive or minimally opioid-tolerant, starting with the lowest effective dose of immediate-release opioid 6
- For acute pain, prescribe immediate-release opioids for ≤3 days in most cases, rarely exceeding 7 days 6
- Titrate cautiously based on clinical response, monitoring for both inadequate analgesia and signs of opioid toxicity 7
Validated Opioid-to-Opioid Conversions
When converting between established pharmaceutical opioids, use evidence-based equianalgesic ratios:
- Oral morphine to oral oxycodone: 1:1.5 ratio (meaning oxycodone is 1.5 times more potent) 8
- Oral to intravenous/subcutaneous morphine: divide oral dose by 3 7
- Always reduce the calculated dose by 25-50% when switching opioids to account for incomplete cross-tolerance 7, 6, 8
Special Caution with Methadone
- Methadone has a long, unpredictable half-life (8-59 hours) and complex pharmacokinetics that make conversion particularly hazardous 9
- The conversion ratio from oral morphine to methadone varies widely from 1:5 to 1:12 or more, depending on prior opioid dose 7
- Initial methadone dosing should not exceed 30 mg, with total first-day dose not ordinarily exceeding 40 mg, regardless of prior opioid use 9
- Methadone should only be prescribed by clinicians with specific training in its risks 6
Critical Clinical Pitfall
The most dangerous error would be assuming kratom use confers significant opioid tolerance and starting high-dose pharmaceutical opioids. Kratom's atypical receptor activity, variable potency, and lack of complete cross-tolerance with traditional opioids make this assumption potentially fatal 2, 1. Loss of tolerance should be considered in any patient who has not taken pharmaceutical opioids for more than 5 days 9.