What medications should not be taken with ashwagandha?

Ashwagandha Drug and Supplement Interactions

Ashwagandha should be avoided or used with extreme caution when taking sedative medications (including anesthetics, benzodiazepines, and barbiturates), thyroid medications, immunosuppressants, blood pressure medications, and central nervous system depressants due to potentially serious additive effects and drug interactions.

Sedative and Anesthetic Interactions

• Ashwagandha has inherent sedative properties that can dangerously potentiate the effects of prescribed sedatives and anesthetics 1
• The supplement can enhance γ-aminobutyric acid (GABA) effects and prolong sedation when combined with benzodiazepines (like diazepam) or barbiturates 1
• This interaction is particularly concerning in perioperative settings where anesthetic medications are metabolized through the cytochrome P-450 pathway, as ashwagandha can alter their safety profile 1
• Avoid ashwagandha entirely when taking any benzodiazepines, barbiturates, or before scheduled surgeries requiring anesthesia 1

Thyroid Medication Interactions

• Ashwagandha can significantly increase serum thyroid hormone concentrations, leading to thyrotoxicosis 2, 3, 4
• Multiple case reports document thyrotoxicosis developing within 2-12 weeks of ashwagandha use, presenting with symptoms including supraventricular tachycardia, weight loss, fatigue, and diarrhea 2, 3, 4
• One case specifically involved a patient who developed thyrotoxicosis after using ashwagandha for self-treatment of hypothyroidism, requiring complete cessation of the supplement 3
• If you are taking levothyroxine or any thyroid replacement therapy, do not use ashwagandha without close thyroid function monitoring, as it can cause dangerous thyroid hormone elevations 2, 3, 4
• Patients with pre-existing thyroid conditions should avoid ashwagandha entirely given the risk of painless thyroiditis 4

Immunosuppressant Interactions

• Ashwagandha may interfere with immunosuppressive medications used after organ transplantation or for autoimmune conditions 1
• This is particularly relevant for kidney transplant recipients or living kidney donors who require careful medication management 1
• The herb's immunomodulatory effects could theoretically reduce the efficacy of drugs like cyclosporine or tacrolimus 1

Blood Pressure Medication Interactions

• Ashwagandha can cause hypotension and should not be combined with antihypertensive medications without medical supervision 1
• The supplement has documented blood pressure-lowering effects that can be additive with prescribed antihypertensives 1
• This interaction poses particular risk in older adults who are already at increased risk for orthostatic hypotension and falls 1

Central Nervous System (CNS) Depressant Interactions

• Avoid combining ashwagandha with multiple CNS-active medications (antidepressants, antipsychotics, antiepileptics, opioids) as this significantly increases fall risk 1
• The American Geriatrics Society specifically warns against concurrent use of three or more CNS agents due to cumulative sedative effects 1
• This is especially critical in adults over 75 years who have heightened susceptibility to drug interactions 1

Hepatotoxicity Considerations

• Ashwagandha has documented hepatotoxic potential, causing cholestatic or mixed liver injury with severe jaundice and pruritus 5
• Liver injury typically develops after 2-12 weeks of use and can result in prolonged hyperbilirubinemia lasting 5-20 weeks 5
• Avoid ashwagandha if you are taking other potentially hepatotoxic medications or supplements, or if you have pre-existing liver disease 5
• The European Association for the Study of the Liver recommends extreme caution with ashwagandha in patients with liver disease 6

Timing and General Precautions

• If drug interaction information is uncertain, take other medications at least 1 hour before or 4-6 hours after ashwagandha administration 6
• This timing strategy helps minimize potential pharmacokinetic interactions through the gastrointestinal tract 6
• Complete medication reconciliation should be performed before starting ashwagandha, including all prescription drugs, over-the-counter medications, and other herbal supplements 1

High-Risk Populations

• Elderly patients (≥75 years) require particularly close monitoring due to increased susceptibility to drug interactions 1, 6
• Patients with cardiovascular disease, especially those on anti-arrhythmic medications, should exercise extreme caution 1
• Those with kidney disease or reduced renal function should avoid ashwagandha given the single-kidney vulnerability to nephrotoxic effects 1