He Shou Wu

HSW-induced hepatotoxicity has an immune-mediated idiosyncratic component. Corticosteroids are sometimes used for HSW-induced liver injury but show no proven benefit (LiverTox). More critically, HSW co-use with immunosuppressants in transplant patients combines hepatotoxic risk with unpredictable pharmacokinetic changes.

He Shou Wu is absolutely contraindicated in transplant patients on calcineurin inhibitors. If HSW-induced liver injury is diagnosed, corticosteroids are NOT routinely recommended - stopping HSW is the primary intervention. Re-challenge after liver injury is absolutely contraindicated.

Reynoutria multiflora causes idiosyncratic drug-induced liver injury via anthraquinone metabolites (emodin, rhein) and stilbene glycoside pathways involving CYP2C19-mediated reactive metabolite formation, mitochondrial damage, and immune-mediated hepatotoxicity. Co-administration with other hepatotoxic drugs compounds liver injury risk additively or synergistically.

He Shou Wu is CONTRAINDICATED with all hepatotoxic medications. CFDA issued a black-box equivalent warning in 2014. Liver function tests (ALT, AST, ALP, bilirubin) are required before initiation, monthly during use, and 4 weeks after stopping. ANY elevation should prompt immediate discontinuation.

THSG from Reynoutria multiflora inhibits CYP2C19 in vitro. CYP2C19 is responsible for clopidogrel bioactivation and diazepam clearance. Inhibition reduces clopidogrel antiplatelet efficacy as clopidogrel requires CYP2C19-mediated activation to its active form. Concurrent use risks cardiovascular events in stented patients.

Avoid HSW in patients on clopidogrel as reduced antiplatelet efficacy risks stent thrombosis and cardiovascular events. Monitor patients on voriconazole closely as CYP2C19 inhibition can cause voriconazole toxicity. For diazepam, watch for prolonged sedation.

Emodin from He Shou Wu inhibits CYP1A2 in vitro and in animal studies. CYP1A2 inhibition impairs metabolism of theophylline, clozapine, and olanzapine, potentially raising plasma concentrations into toxic ranges. Theophylline has a narrow therapeutic index with toxicity risk at elevated levels.

Monitor theophylline levels closely when HSW is used concurrently. For clozapine or olanzapine, watch for toxicity signs including sedation and metabolic effects. Given HSW hepatotoxicity risk, co-use with clozapine (which also carries agranulocytosis risk) is particularly inadvisable.

He Shou Wu contains anthraquinone glycosides (emodin, physcion) with stimulant laxative properties. Combined with pharmaceutical laxatives, additive effects can cause severe diarrhea, dehydration, electrolyte imbalances, and reduced absorption of other oral medications. Prolonged anthraquinone exposure increases hepatotoxicity risk.

Avoid combining HSW with stimulant laxatives. Monitor for electrolyte imbalance signs such as weakness and cardiac arrhythmias. In patients on diuretics or digoxin, hypokalemia from combined laxative effects is particularly dangerous.

THSG in He Shou Wu has demonstrated vasodilatory and mild antihypertensive properties in preclinical studies. When combined with antihypertensive medications, additive blood pressure-lowering effects are theoretically possible, though clinical significance at typical doses is low.

Monitor blood pressure when starting HSW in patients on antihypertensive therapy. The significant hepatotoxicity risk of HSW far outweighs any antihypertensive benefit; evidence-based alternatives should be recommended instead.