Kratom Causes Reversible Liver Injury and Dangerous Drug Interactions Via CYP Enzymes: Case Report

Why it matters

This peer-reviewed case report documents that chronic kratom use caused reversible liver enzyme elevations and dangerously elevated levels of the antidepressant nortriptyline by blocking CYP liver enzymes — a clinically significant interaction with broad implications for the millions of Americans who take prescription medications while using kratom.

The big picture

Kratom's active alkaloids, particularly mitragynine, are known to inhibit cytochrome P450 enzymes (CYP3A4, CYP2D6, CYP2C9) that metabolize many prescription drugs. As kratom use continues to grow across the U.S., clinicians increasingly need to screen patients for herbal supplement use and monitor liver function and drug levels accordingly. Concentrated kratom products and extracts — including those enriched with 7-hydroxymitragynine — may carry even higher risk than raw leaf preparations.

Key findings

• A 45-year-old patient on nortriptyline developed dangerously high drug levels (350 mcg/L vs. therapeutic 50–150 mcg/L) during 5-6 years of daily kratom use
• Liver enzymes (ALT, GGT) were persistently elevated throughout kratom use but fully normalized within 3 weeks of stopping
• Reducing the nortriptyline dose alone only partially corrected drug levels — full normalization required kratom discontinuation
• The case meets RUCAM criteria for 'probable' herb-induced liver injury (HILI)
• Raw dry-leaf kratom products were used; concentrated extracts and 7-OH-enriched formulations may carry even higher hepatotoxic and drug-interaction risk

What they say

"Even mild liver enzyme elevations in patients using kratom warrant evaluation, particularly with concurrent CYP-metabolized medications," wrote authors Gnanasegaram and Stanciu of Dartmouth Hitchcock Medical Center, adding that "clinicians should maintain vigilance for both hepatotoxicity and herb-drug interactions."

Bottom line

Kratom can cause reversible liver damage and dramatically increase blood levels of CYP-metabolized prescription drugs — clinicians must ask about kratom use in any patient on medications like antidepressants, antipsychotics, or opioids.