NutriStack
Magnesium Citrate and Nifedipine, a caution.
Magnesium is a physiologic calcium-channel modulator that lowers blood pressure by about 2 mmHg systolic at supplemental doses. Combined with nifedipine's strong dihydropyridine vasodilation, the additive effect can produce symptomatic hypotension, headache, flushing, or reflex tachycardia, particularly in pregnant patients receiving magnesium for preeclampsia (a well-known severe interaction).
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.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Magnesium Citrate and Nifedipine
- 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-channel modulator that lowers blood pressure by about 2 mmHg systolic at supplemental doses. Combined with nifedipine's strong dihydropyridine vasodilation, the additive effect can produce symptomatic hypotension, headache, flushing, or reflex tachycardia, particularly in pregnant patients receiving magnesium for preeclampsia (a well-known severe interaction).
Mechanism. Magnesium competes with calcium at vascular smooth muscle L-type calcium channels and enhances endothelial NO. These effects add to nifedipine's calcium channel blockade and vasodilation.
Recommendation. If you take nifedipine, keep oral magnesium citrate to 200-350 mg/day supplemental elemental magnesium and monitor blood pressure when you start. Reduce or stop magnesium if readings drop below your usual range. Pregnant patients on IV magnesium should be co-managed by their obstetrician and avoid concurrent nifedipine without monitoring.
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
- Bailey DG, Malcolm J, Arnold O, Spence JD. Grapefruit juice-drug interactions. Br J Clin Pharmacol. 1998;46(2):101-10. PMID 9723817
Stack Score
How this pair moves the number.
Effect on the composite score
If both Magnesium Citrate and Nifedipine 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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