What medications cannot be taken with ashwagandha? A guide to safe supplementation

October 26, 2025 •

3 min read

While ashwagandha has been used for centuries in Ayurvedic medicine, it's not safe to combine with all medications. It is crucial to understand what medications cannot be taken with ashwagandha, as interactions can lead to serious side effects ranging from dangerously low blood sugar to increased bleeding risk.

Quick Summary

Ashwagandha should not be combined with sedatives, immunosuppressants, thyroid hormones, blood pressure medications, or blood thinners due to potential interactions that can worsen health conditions or lead to severe side effects.

Key Points

Avoid CNS Depressants: Ashwagandha's sedative effects can dangerously intensify medications like benzodiazepines, opioids, and sleep aids.
Do Not Combine with Immunosuppressants: The herb can stimulate the immune system, interfering with medications used for organ transplants or autoimmune diseases.
Monitor Thyroid Function: Ashwagandha can increase thyroid hormone levels, potentially causing an overactive thyroid if taken with thyroid medication.
Watch for Hypoglycemia: Combining ashwagandha with anti-diabetes drugs could cause dangerously low blood sugar levels.
Be Cautious with Blood Pressure Meds: Ashwagandha can lower blood pressure, which may cause hypotension when combined with antihypertensive drugs.
Increased Bleeding Risk: Ashwagandha may enhance the effects of blood thinners, so concurrent use should be avoided.
Seek Medical Advice Before Use: Always consult a healthcare provider, especially if you have pre-existing conditions or are on any medication.

Navigating Ashwagandha's Drug Interactions

Ashwagandha (Withania somnifera) is an adaptogenic herb revered for its potential benefits in managing stress, anxiety, and improving sleep. However, its powerful biological effects mean it can interact negatively with a range of prescription and over-the-counter medications. Understanding these potential drug interactions is critical for anyone considering this supplement, particularly those with pre-existing health conditions.

Sedatives and Central Nervous System (CNS) Depressants

Ashwagandha is known for its calming and sedative properties. Combining it with other CNS depressants can amplify these effects, leading to excessive drowsiness, fatigue, and dangerously slowed breathing. This combination should be strictly avoided. Medications that interact with ashwagandha in this manner include:

Benzodiazepines: Medications like alprazolam (Xanax), clonazepam (Klonopin), and lorazepam.
Sleep medications: Hypnotics such as zolpidem (Ambien).
Opioid pain medications: Drugs like oxycodone.
Barbiturates: Phenobarbital.

Immunosuppressants

Ashwagandha can enhance the activity of the immune system. This is a concern for individuals with autoimmune diseases or those who have undergone organ transplantation and are on immunosuppressant therapy. By stimulating the immune system, ashwagandha can counteract the desired effect of these medications, potentially leading to treatment failure or worsening autoimmune symptoms. Immunosuppressant medications include:

Corticosteroids: Such as prednisone.
Transplant medications: Including tacrolimus (Prograf) and azathioprine (Imuran).
Certain chemotherapies.

Thyroid Medications

Studies suggest ashwagandha may increase thyroid hormone levels (T3 and T4). For people taking thyroid hormone replacement medications, such as levothyroxine (Synthroid) or liothyronine (Cytomel), this combination could lead to an overactive thyroid state (thyrotoxicosis) with symptoms like nervousness, sleep trouble, and irregular heartbeat. People with thyroid conditions should consult their doctor and have their hormone levels closely monitored.

Medications for Diabetes

Ashwagandha has been shown to lower blood glucose levels. This effect is concerning when combined with anti-diabetes drugs, which also lower blood sugar. The combined effect can lead to hypoglycemia (low blood sugar), which can cause weakness, dizziness, and confusion. Diabetes medications to be cautious with include:

Insulin.
Metformin (Glumetza).
Glipizide (Glucotrol).
Semaglutide (Ozempic).

Antihypertensive Medications (Blood Pressure Drugs)

Because ashwagandha can lower blood pressure, combining it with other antihypertensive medications can cause blood pressure to drop too low (hypotension). This can result in fainting, dizziness, or lightheadedness. Examples of interacting medications include:

Beta-blockers (e.g., atenolol).
ACE inhibitors (e.g., lisinopril).
Calcium channel blockers (e.g., amlodipine).
Diuretics (e.g., furosemide).

Anticoagulants and Antiplatelets

Ashwagandha may increase blood coagulation time and enhance the effects of blood-thinning medications. This can raise the risk of bleeding, especially for those on anticoagulants like warfarin. The safest course of action is to avoid this combination completely.

Medications That Can Harm the Liver (Hepatotoxic Drugs)

Although rare, ashwagandha has been linked to liver injury. Taking it alongside other hepatotoxic drugs can increase the risk of liver damage. Regular monitoring of liver function is necessary when combining ashwagandha with such medications.

Ashwagandha Medication Interaction Comparison Table


Medication Class	Ashwagandha's Effect	Potential Interaction	Risk Level
Sedatives/CNS Depressants	Causes drowsiness/sleepiness	Excessive sedation, slowed breathing	High
Immunosuppressants	Stimulates immune system	Counteracts medication effectiveness	High
Thyroid Medications	Increases thyroid hormones	Overactive thyroid, hormone imbalance	High
Diabetes Medications	Lowers blood sugar	Dangerously low blood sugar (hypoglycemia)	High
Antihypertensives	Lowers blood pressure	Dangerously low blood pressure (hypotension)	Medium-High
Anticoagulants/Antiplatelets	May increase bleeding risk	Enhanced bleeding risk	High
Hepatotoxic Medications	Potential liver harm	Increased risk of liver damage	Medium-High

Conclusion

While ashwagandha offers several potential health benefits, it is crucial to recognize its significant potential for drug interactions with a wide range of common medications. The risk of serious side effects, including excessive sedation, dangerous blood sugar fluctuations, and compromised immune or thyroid function, makes consultation with a healthcare professional non-negotiable before combining ashwagandha with any prescription or over-the-counter drugs. For more comprehensive information on herbal supplements and their interactions, consult authoritative sources like the National Center for Complementary and Integrative Health (NCCIH).

Additional Considerations and Warnings

Pre-Surgery: Discontinue ashwagandha at least two weeks before any scheduled surgery due to its CNS depressant effects.
Autoimmune Diseases: Avoid ashwagandha if you have an autoimmune disease, such as lupus, multiple sclerosis, or rheumatoid arthritis, as it may worsen symptoms.
Pregnancy and Breastfeeding: Ashwagandha is considered unsafe during pregnancy and should be avoided. There is insufficient evidence to confirm safety while breastfeeding.
Liver Disease: Individuals with liver disease should avoid ashwagandha due to the rare risk of liver damage.

Frequently Asked Questions

There is insufficient research on combining ashwagandha with Selective Serotonin Reuptake Inhibitors (SSRIs). Some studies indicate a potential for increased serotonin levels, which could theoretically cause serotonin syndrome. It is crucial to consult your doctor before combining them.

Yes, ashwagandha should be stopped at least two weeks before any scheduled surgery. The herb can slow down the central nervous system, and combining it with anesthesia can cause excessive sedation.

Yes, ashwagandha may increase bleeding risk by enhancing the effects of anticoagulant and antiplatelet medications like warfarin. This combination should be avoided.

No, people with autoimmune diseases like lupus, multiple sclerosis, or rheumatoid arthritis should avoid ashwagandha. It can stimulate the immune system, potentially worsening symptoms.

Ashwagandha may increase thyroid hormone levels. If you are taking thyroid hormone replacement therapy, combining it with ashwagandha could lead to an overactive thyroid and related side effects. Any combination should be monitored closely by a doctor.

No, it is not recommended for people with liver disease. In rare cases, ashwagandha has been linked to liver damage, and combining it with pre-existing liver issues or other hepatotoxic drugs increases the risk.

You should not take ashwagandha with high blood pressure medication without strict medical supervision. As ashwagandha can lower blood pressure, combining it with antihypertensives could cause dangerously low blood pressure.