NutriStack
Diltiazem and Garlic Extract, a caution.
Aged garlic extract reduces systolic and diastolic blood pressure by about 8 and 5 mmHg in hypertensive patients. Combined with diltiazem's vasodilatory and rate-slowing effects, the additive antihypertensive response can be welcome but also risks symptomatic hypotension or dizziness, especially in older patients or those at goal blood pressure.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
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At a glance
- Substances
- Diltiazem and Garlic Extract
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. Aged garlic extract reduces systolic and diastolic blood pressure by about 8 and 5 mmHg in hypertensive patients. Combined with diltiazem's vasodilatory and rate-slowing effects, the additive antihypertensive response can be welcome but also risks symptomatic hypotension or dizziness, especially in older patients or those at goal blood pressure.
Mechanism. Garlic organosulfur compounds increase endothelial NO and modestly reduce ACE activity, adding to diltiazem's L-type calcium channel blockade and vasodilation.
Recommendation. If you take diltiazem, monitor blood pressure and pulse for 2-4 weeks after starting garlic extract. Reduce or stop garlic if readings drop below your usual range, you become dizzy, or your heart rate falls below 50 bpm.
Sources (2)
- Ried K. Garlic lowers blood pressure in hypertensive subjects, improves arterial stiffness and gut microbiota: A review and meta-analysis. Exp Ther Med. 2020;19(2):1472-1478. PMID 32010325
- Mills TA, Kawji MM, Cataldo VD, et al. Profound sinus bradycardia due to diltiazem, verapamil, and/or beta-adrenergic blocking drugs. J La State Med Soc. 2004;156(6):327-31. PMID 15688675
Stack Score
How this pair moves the number.
Effect on the composite score
If both Diltiazem and Garlic Extract are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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