Vasovagal reactions after blood donations in patients under sartans

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3943146/

"The reports of severe syncope in association with the use of valsartan in the VALUE trial seemingly, therefore, add further support to the hypothesis2 that blockade of angiotensin II type I receptors removes the modulating Correspondence effects of angiotensin II on the BezoldJarisch reflex and, particularly in circumstances when a vaso-vagal reaction is likely to arise, there is sensitisation of the pathway and exaggeration of the withdrawal of sympathetic tone, vasodilatation, and profound bradycardia. Despite the fact that drug-related and dose-related side effects have not been identified in placebo-controlled trials of ARBs, postmarketing surveillance studies have reported dizziness as one of the most common symptoms associated with the use of these drugs. The identification of an uncommon side-effect of a drug depends on clinical vigilance and doctors should be aware of this possible adverse reaction to ARBs, particularly in the context of their increasing use in the management of hypertension and heart failure. "

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(04)17013-X.pdf