Intravenous dihydropyridine calcium channel blockers can quietly worsen oxygenation by blunting hypoxic pulmonary vasoconstriction. In this episode, we break down the bedside mechanism, which agents are implicated, who’s at highest risk (post-op atelectasis, obesity, pneumonia, focal ARDS, COPD), how soon it happens, and exactly what to do.

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Citations:

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Lumb AB, Slinger P. Hypoxic pulmonary vasoconstriction: physiology and anesthetic implications. Anesthesiology. 2015 Apr;122(4):932-46. doi: 10.1097/ALN.0000000000000569. PMID: 25587641.

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McMurtry IF, Davidson AB, Reeves JT, Grover RF. Inhibition of hypoxic pulmonary vasoconstriction by calcium antagonists in isolated rat lungs. Circ Res. 1976 Feb;38(2):99-104. doi: 10.1161/01.RES.38.2.99. PMID: 1245025.

Simonneau G, Escourrou P, Duroux P, Lockhart A. Inhibition of hypoxic pulmonary vasoconstriction by nifedipine. N Engl J Med. 1981 Jun 25;304(26):1582-5. doi: 10.1056/NEJM198106253042606. PMID: 7231503.

Kennedy T, Summer W. Inhibition of hypoxic pulmonary vasoconstriction by nifedipine. Am J Cardiol. 1982 Oct;50(4):864-8. doi: 10.1016/0002-9149(82)91246-2. PMID: 7124646.

Chrétien B, Decros JB, Suard F, Dolladille C, Fischer MO, Alexandre J, Descamps R. Hypoxia Associated With Dihydropyridine Calcium Channel Inhibitors: A Pharmacovigilance Study in VigiBase. Clin Pharmacol Ther. 2023 Sep;114(3):686-692. doi: 10.1002/cpt.2970. Epub 2023 Jun 29. PMID: 37309986.

Burghuber OC. Nifedipine attenuates acute hypoxic pulmonary vasoconstriction in patients with chronic obstructive pulmonary disease. Respiration. 1987;52(2):86-93. doi: 10.1159/000195309. PMID: 3671896.

Suard F, Mombrun M, Fischer MO, Hanouz JL, Decros JB, Derville S, Gakuba C, Al Issa G, Menard C, Chretien B, Descamps R. Oxygenation Effects of Antihypertensive Agents in Intensive Care: A Prospective Comparative Study of Nicardipine and Urapidil. Clin Pharmacol Ther. 2025 Mar;117(3):742-748. doi: 10.1002/cpt.3509. Epub 2024 Nov 27. PMID: 39604146.