NutriStack
Diltiazem and Magnesium Citrate, a caution.
Magnesium is a physiologic calcium antagonist that lowers blood pressure by about 2/1.8 mmHg at supplemental doses and also blunts sinoatrial and AV-nodal conduction. Combined with diltiazem's rate-slowing and vasodilatory effects, the result can be additive bradycardia, hypotension, or AV-nodal slowing, particularly with high magnesium doses or IV use.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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At a glance
- Substances
- Diltiazem and Magnesium Citrate
- 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. Magnesium is a physiologic calcium antagonist that lowers blood pressure by about 2/1.8 mmHg at supplemental doses and also blunts sinoatrial and AV-nodal conduction. Combined with diltiazem's rate-slowing and vasodilatory effects, the result can be additive bradycardia, hypotension, or AV-nodal slowing, particularly with high magnesium doses or IV use.
Mechanism. Magnesium competes with calcium at vascular and cardiac calcium channels and slows AV-nodal conduction. These effects overlap with diltiazem's L-type calcium channel blockade.
Recommendation. If you take diltiazem, keep oral magnesium citrate to 200-350 mg/day supplemental elemental magnesium and monitor blood pressure and pulse after starting. Reduce or stop magnesium if your HR drops below 50 bpm, you develop dizziness, or your BP falls below your usual range. Avoid IV magnesium without specialist supervision.
Sources (2)
- Zhang X, Li Y, Del Gobbo LC, et al. Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo-Controlled Trials. Hypertension. 2016;68(2):324-33. PMID 27402922
- 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 Magnesium Citrate 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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