NutriStack Data Report

Dangerous Supplement and Medication Interactions

We analyzed NutriStack's evidence-graded interaction database to identify which dietary supplements most often collide with prescription medications, which medications show the most risky supplement pairings, and which strongest-evidence combinations deserve extra caution.

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Report snapshot

Total pairs analyzed: 1,360
High-risk share: 34%
Contraindicated / avoid: 93
Strong-evidence high-risk: 190

Medical disclaimer

Informational only. This report is not medical advice and is not a substitute for a clinician or pharmacist. Never start, stop, or change a supplement or medication based on this page. Ask a qualified clinician or pharmacist about your own medications, health conditions, doses, and timing. The absence of a pair here does not mean it is safe.

Key findings

What the snapshot shows.

These findings use only the locked statistics in the report data file.

Summary

467 of 1,360 analyzed pairs carry major or contraindicated risk, a 34% share.
93 pairs are contraindicated or avoid-level combinations in this snapshot.
190 high-risk pairs have strong evidence, with 182 moderate and 95 emerging.
Warfarin tops the medication list with 23 risky supplement interactions.
St. John's Wort tops the supplement list with 89 risky medication interactions.
The strongest-evidence avoid list contains 189 high-risk combinations in the locked snapshot.

Medications

The medications with the most risky supplement interactions.

Each row links to the medication profile in the NutriStack research library.

Top medications

Medication	Risky supplement interactions
Warfarin	23
Ciprofloxacin	14
Doxycycline	10
Digoxin	9
Levofloxacin	9
Glyburide	8
Sertraline	6
Amiodarone	6
Insulin Glargine	6
Insulin Aspart	6
Insulin Lispro	6
Pramlintide	6

Supplements

The supplements involved in the most risky interactions.

Each row links to the supplement profile in the NutriStack research library.

Top supplements

Supplement	Risky medication interactions
St. John's Wort	89
Potassium	45
5-HTP	28
L-Tryptophan	24
Magnesium Glycinate	20
Ginkgo Biloba	17
Calcium	14
Nattokinase	14
Iron	12
Berberine	12
SAMe	10
Lithium Orotate	8

Avoid combinations

Strongest-evidence combinations to avoid.

The table links each combination to its full pair page, including mechanism, recommendation, and sources.

Flagship combinations

Combination	Risk	What happens	Source
Acitretin + Vitamin A	Avoid	Acitretin is a systemic retinoid with vitamin A-like toxicity. Adding preformed vitamin A supplements can stack retinoid effects and increase the risk of...	PMID 20423353
Amiodarone + Ciprofloxacin	Avoid	Both amiodarone and fluoroquinolones independently prolong the QT interval. Concurrent use creates additive QT prolongation risk, potentially leading to...	PMID 33073581
Calcitriol + Vitamin D3	Avoid	Additional vitamin D can increase the risk of vitamin D toxicity and hypercalcemia during calcitriol therapy.	See sources
Ceftriaxone + Calcium	Avoid	Ceftriaxone and calcium-containing IV fluids can form insoluble ceftriaxone-calcium precipitates in lung and kidney tissue, with fatal cases reported in...	PMID 18759704
Citalopram + 5-HTP	Avoid	5-HTP combined with citalopram creates serotonin syndrome risk. Citalopram also prolongs QTc, and serotonin excess can worsen cardiac effects.	PMID 15784664
Citalopram + St. John's Wort	Avoid	Dual serotonin reuptake inhibition from citalopram and St. John's Wort creates serotonin syndrome risk.	PMID 10447148
Citalopram + L-Tryptophan	Avoid	L-Tryptophan is the upstream precursor to serotonin. Combined with citalopram's serotonin reuptake blockade, supplemental tryptophan can push synaptic...	PMID 15784664
Combined Oral Contraceptive + St. John's Wort	Avoid	St. John's Wort induces CYP3A4, dramatically reducing levels of ethinyl estradiol and progestins. This causes contraceptive failure and unintended pregnancy....	PMID 14663455
Cyclosporine + St. John's Wort	Avoid	St. John's Wort can markedly reduce cyclosporine concentrations and has been associated with transplant rejection.	See sources
Duloxetine + St. John's Wort	Avoid	Combining duloxetine (an SNRI) with St. John's Wort creates a serious risk of serotonin syndrome. Both agents increase synaptic serotonin through different...	PMID 15784664
Eplerenone + Potassium	Avoid	Eplerenone is a mineralocorticoid receptor antagonist that can raise serum potassium. Adding potassium supplements can push potassium into a dangerous range,...	PMID 18824643
Escitalopram + St. John's Wort	Avoid	Combining escitalopram with St. John's Wort significantly increases the risk of serotonin syndrome. Escitalopram is the most selective SSRI, and adding St....	PMID 15784664
Fluoxetine + St. John's Wort	Avoid	Combining fluoxetine with St. John's Wort creates a high risk of serotonin syndrome. Fluoxetine has a long half-life (including its active metabolite...	PMID 15784664
Fluoxetine + Tramadol	Avoid	Fluoxetine combined with tramadol creates dual serotonin syndrome risk. Additionally, fluoxetine inhibits CYP2D6, reducing tramadol conversion to its active...	PMID 19724751
Fluvoxamine + 5-HTP	Avoid	5-HTP is the immediate precursor to serotonin and bypasses the rate-limiting step in serotonin synthesis. Combined with fluvoxamine's blockade of the serotonin...	PMID 15784664
Fluvoxamine + L-Tryptophan	Avoid	L-Tryptophan is the upstream precursor to serotonin; combined with fluvoxamine's serotonin reuptake blockade, it can drive synaptic serotonin to toxic levels...	PMID 15784664
Fluvoxamine + St. John's Wort	Avoid	St. John's Wort has SSRI-like activity and is a strong CYP3A4/2C9 inducer. Combined with fluvoxamine, the additive serotonergic load can trigger serotonin...	PMID 19719333
Hydrocodone + Alprazolam	Avoid	FDA Black Box Warning: The combination of hydrocodone and alprazolam carries severe risk of fatal respiratory depression. This is among the most commonly...	PMID 28292769
Isocarboxazid + Tyramine / High-Tyramine Foods	Avoid	Isocarboxazid is an irreversible MAOI that can sharply reduce tyramine breakdown. High-tyramine foods can then trigger sudden, severe blood-pressure elevation...	PMID 3525654
Isocarboxazid + 5-HTP	Avoid	5-HTP increases serotonin synthesis while Isocarboxazid reduces monoamine breakdown. Combining them can cause dangerous serotonergic excess and serotonin...	PMID 15784664

Evidence confidence

How confident is this evidence.

High-risk records are tiered by the strength and directness of the supporting literature.

Evidence tiers

Strong evidence: 190
Moderate evidence: 182
Emerging evidence: 95

Strong means the interaction is supported by direct clinical evidence, replicated human evidence, authoritative labeling, or closely aligned high-quality reviews. Moderate means the signal is supported but narrower, less replicated, or partly extrapolated. Emerging means the mechanism or early human evidence is credible but less settled.

Methodology

How this report was built.

The report is a database snapshot, not a clinical decision tool.

Scope and definitions

Data source. NutriStack interaction database, compiled from PubMed/MEDLINE, Cochrane, NIH ODS, EFSA, and EMA references, then organized into evidence-graded interaction records.

High-risk definition. High-risk means a pair classified as major or contraindicated/avoid in the locked snapshot. Contraindicated/avoid means the record recommends avoiding the combination unless a qualified clinician specifically directs otherwise.

Scope. This report covers dietary supplement and prescription drug pairs in the NutriStack interaction database. Recreational substances were excluded from this report snapshot.

Last updated. June 7, 2026. This is a snapshot. The report will grow as the database expands and as new evidence is reviewed.

Medical disclaimer, repeated

Next step

Check your own stack.

Use the free interaction checker, then discuss medication or supplement changes with a clinician or pharmacist.

Open the interaction checker →Download on the App Store