Is ashwagandha safe for patients with impaired renal (kidney) function?

Ashwagandha Safety in Kidney Disease

I do not recommend ashwagandha for patients with impaired kidney function due to lack of safety data in this population, potential hepatotoxicity that could complicate management, and the general guideline principle to avoid herbal remedies in chronic kidney disease.

Guideline-Based Recommendations

Primary Contraindication in CKD

• KDIGO guidelines explicitly recommend against using herbal remedies in people with CKD 1
• This recommendation applies regardless of CKD stage and reflects the lack of safety data, unpredictable pharmacokinetics, and potential for organ toxicity 1

Medication Safety Principles in Kidney Disease

• Patients with CKD should seek medical or pharmacist advice before using over-the-counter medicines or nutritional supplements 1
• Nephrotoxic medications or combinations should be avoided in patients with acute kidney disease (AKD), and when clinically necessary, efforts must be made to mitigate nephrotoxic effects 1
• Drug selection in kidney disease must consider potential for nephrotoxicity, renal versus non-renal excretion, and availability of suitable alternatives 1

Evidence-Specific Concerns with Ashwagandha

Hepatotoxicity Risk

• Ashwagandha has documented hepatotoxic potential with cholestatic or mixed liver injury patterns 2
• Five cases demonstrated jaundice, severe pruritus, and hyperbilirubinemia lasting 5-20 weeks after 2-12 weeks of use 2
• Liver injury was self-limited but required 1-5 months for normalization 2
• This hepatotoxicity is particularly concerning in kidney disease patients who already have altered drug metabolism and increased vulnerability to multi-organ complications 1

Lack of Renal Safety Data

• No studies have specifically evaluated ashwagandha safety in patients with impaired renal function 3, 4
• The only safety study in humans evaluated healthy volunteers with normal kidney function for 8 weeks, showing no renal toxicity 4
• A rheumatoid arthritis study showed normal kidney function tests after 7 weeks, but this was in patients without baseline kidney disease 3

Altered Pharmacokinetics in Kidney Disease

• Acute kidney injury significantly impairs cytochrome P450 activity and drug metabolism, which can affect clearance and increase drug levels 5
• The effects of kidney disease on herbal supplement metabolism are poorly characterized compared to prescription medications 5
• Organ crosstalk between liver and kidney during AKI can influence drug metabolism through effects on hepatic blood flow and protein binding 5

Clinical Decision Algorithm

For patients with any stage of CKD (eGFR <60 mL/min/1.73m²):

1. Do not initiate ashwagandha - follows KDIGO guideline to avoid herbal remedies 1
2. If already taking, discontinue and monitor liver function tests for 3-6 months given hepatotoxicity risk 2

For patients with acute kidney injury:

1. Absolutely avoid ashwagandha - follows consensus to avoid nephrotoxic medications when possible 1
2. Multiple medications increase AKI risk by 53% per additional agent 6

For patients with normal kidney function considering ashwagandha:

1. Baseline liver and kidney function tests required 4
2. Monitor hepatic function (ALT, AST, alkaline phosphatase, bilirubin) every 4 weeks 3, 4
3. Discontinue immediately if jaundice, pruritus, or elevated liver enzymes develop 2

Critical Pitfalls to Avoid

• Do not assume "natural" means safe - ashwagandha has documented organ toxicity 2
• Do not use in combination with other potentially hepatotoxic or nephrotoxic medications - drug interactions are amplified and unpredictable in kidney disease 1, 5
• Do not continue if any signs of liver injury develop (jaundice, dark urine, pruritus, right upper quadrant pain) - these can progress to severe cholestatic injury 2
• Do not rely on traditional use as evidence of safety - systematic evaluation shows hepatotoxicity risk that was not previously recognized 2

Mechanistic Considerations

While ashwagandha demonstrates anti-inflammatory properties in vitro, including attenuation of TNF-α and LPS-induced chemokine expression and NF-κB activation in kidney cells 7, these laboratory findings do not translate to clinical safety recommendations in patients with actual kidney disease. The risk-benefit ratio is unfavorable given documented hepatotoxicity, lack of renal safety data, and explicit guideline recommendations against herbal remedy use in CKD 1, 2.