Q: 54 year old male is admitted via ER to ICU with hypertensive crisis. ER physician chose to use IV Fenoldopam in view of patient's baseline renal insufficiency with creatinine of 2.5. Patient showed partial response to Fenoldopam. You decided to add Esmolol as second anti-hypertensive. After 15 minutes of addition and titration of Esmolol, patient acutely became hypotensive and coded. What could be the explanation?

Answer: Fenoldopam does not only have a selective D1 receptor agonist effect but also have some alpha-1 and alpha-2 adrenoceptor antagonist activity. It may cause sympathetic-mediated reflex tachycardia and concomitant use of beta-blocker should be avoided, as unexpected hypotension can result from beta-blocker inhibition of tachycardia.