Is Ashwagandha safe for patients with Impaired Renal (kidney) Function?

Is Ashwagandha Safe for Patients with Impaired Renal Function?

Ashwagandha should be avoided in patients with impaired renal function due to lack of safety data in this population, potential for nephrotoxicity from herbal supplements, and the risk of undisclosed adulterants or drug interactions that could harm the remaining kidney function.

Evidence Against Use in Kidney Disease

Guideline Recommendations on Herbal Supplements in CKD

• Living kidney donors, who represent the healthiest kidney population with only one kidney, are explicitly advised to avoid dietary supplements (excluding multivitamins and minerals) due to unknown effects on kidney function and metabolic parameters 1.

• The rationale for this conservative approach is that even in the healthiest single-kidney population, the absolute risk of kidney failure remains elevated, making any potential nephrotoxic exposure unacceptable 1.

• If avoidance is recommended even for healthy donors with one kidney, the same principle applies with greater force to patients with already impaired renal function 1.

Specific Concerns with Herbal Products in CKD

• Internet-marketed herbal supplements claiming kidney benefits, including common ingredients like horsetail, dandelion, and stinging nettle, lack adequate human studies and have shown detrimental effects in animal models 2.

• Over 90% of herbal supplement websites fail to mention potential drug interactions, disease interactions, or cautions for use in patients with kidney disease 2.

• Several herbal products can raise potassium levels, including horsetail, dandelion, and nettle—all commonly marketed for kidney health—creating hyperkalemia risk in CKD patients 1.

Lack of Safety Data for Ashwagandha in Renal Impairment

• While one in vitro study showed ashwagandha water-soluble extract reduced inflammatory markers in kidney cells 3, this laboratory finding does not translate to clinical safety or efficacy in humans with kidney disease.

• A clinical trial of ashwagandha in rheumatoid arthritis patients showed normal kidney function tests after 7 weeks 4, but this study had major limitations: small sample size, short duration, no control group, and importantly, it did not specifically include patients with pre-existing renal impairment 4.

• The study population had normal baseline kidney function, making these findings irrelevant to the safety question in patients with impaired renal function 4.

Real-World Risks in CKD Population

• Among CKD patients using herbal supplements, 18.6% reported use, but only 21% had knowledge of possible side effects 5.

• Patients with CKD are at higher risk for herb-drug interactions, with ginseng alone having 18 documented interactions with prescription drugs, 6 of which were severe 6.

• The decision to use supplements was patient-initiated in 37% of cases, bypassing medical oversight 5.

Perioperative and Sedation Concerns

• Ashwagandha has documented sedative properties that can potentiate anesthetic agents, creating additional risk during procedures or surgeries that CKD patients may require 1.

• This interaction is particularly concerning given that CKD patients frequently undergo procedures requiring sedation or anesthesia 1.

Clinical Algorithm for Decision-Making

When a patient with impaired renal function asks about ashwagandha:

1. Advise against use due to absence of safety data in renal impairment 1, 2

2. Explain specific risks:

   • Unknown nephrotoxic potential 1, 2
   • Possible hyperkalemia (if combined with other herbs) 1
   • Drug interactions with common CKD medications 6
   • Sedative effects complicating medical care 1

3. If patient insists on herbal approaches:

   • Redirect to evidence-based interventions: dietary modifications, blood pressure control, and proven medications (SGLT2 inhibitors, RAS inhibitors) 1
   • Emphasize that no herbal supplement has proven kidney-protective effects in humans 2

4. Document the discussion and patient's decision in the medical record

Common Pitfalls to Avoid

• Do not assume "natural" means safe—the lack of regulation means products may contain nephrotoxic adulterants like aristolochic acid 1, 2.

• Do not rely on normal liver/kidney tests from short-term studies in healthy populations to extrapolate safety in CKD 4.

• Do not fail to ask about supplement use at every visit—patients often do not volunteer this information and may not consider it a "medication" 5, 6.

• Do not ignore the cumulative risk—CKD patients are already on multiple medications with renal dosing requirements, and adding supplements with unknown pharmacokinetics compounds the risk 1, 6.