Management of hypertensive crises in the el(3)

Wood and coworkers showed that elderly patients are at a particular risk for developing complications when re-ceiving nitroprusside; and that hypotension is very common among them.[39] The ECLIPSE trial compared nitroprusside versus other antihypertensives; it showed that this agent caused higher mortality when compared with other agents.[40] From our standpoint, nitroprusside should only be used when other safer alternatives are not available, especially among elderly patients.

5.3 Nifedipine

Nifedipine is a first generation calcium channel blocker.[41] For a period of time, it had been used widely through oral and sublingual capsules for the management of hypertensive crises.[16] However, it is poorly soluble, and poorly absorbed through the buccal mucosa, and swallowing the drug is the only effective method of administration.[42] The American Geriatrics Society, in the updated Beers criteria, strongly recommended avoiding nifedipine in patients older than 65 years, due to the potential risk of hypotension, which may precipitate for myocardial ischemia.[43] In addition, in elderly patients, it can cause a rapid fall in BP, coronary steal syndrome, and reflex tachycardia.[44,45] Given those serious side effects and complete lack of outcome data, Grossman and coworkers pointed out that in true hypertensive emergencies, this agent is contraindicated.[44]

5.4 Nicardipine

Nicardipine is a second generation dihydropyridine L- type calcium channel blocker.[41] It is highly selective to vessels without affecting cardiac contractility.[46] It is a potent coronary dilator as it is more selective to coronary beds than systematic beds.[33] In a retrospective analysis to compare nicardipine to labetalol in managing HTN in critically-ill patients, Malesker and Hilleman found that nicardipine was as efficacious as labetalol with significantly fewer side effects, which were mainly hypotension and bradycardia.[47] Although it has been reported to cause bradycardia in elderly patients,[48] tachycardia is a more common side effect.[49] Animal studies have shown a direct sympathetic activator effect, in addition to its effects through baroreflex.[50] Additional side effects include headache, flushing, and local phlebitis after prolonged infusion in a single site.[49] Nicardipine is rapidly and extensively metabolized by the liver and should be avoided in patients with hepatic impairment.[33] The manufacturer dose range is between 5–15 mg/hr, but in our experience, up to 25 mg/hr can be tolerated safely.[1,51]

5.5 Clevidipine

Clevidipine is the newest, ultrashort, dihydropyridine calcium channel blocker.[52] It is a pure arteriodilator, and does not affect the venous tone or cardiac muscle contractility.[53] It is given as a lipid emulsion as it is water in-so-luble.[54] This agent should be avoided in patients with egg and soybean allergy.[55] It has rapid onset and offset of ac-tion. It has been shown to achieve the first 15% reduction in SBP within 5–6 minutes of intravenous administration.[56,57] Its antihypertensive effects are abolished 5–15 minutes after weaning off the medication in most patients.[55]

Clevidipine had also achieved significant reduction in BP in patients with acute HTN when compared to placebo in the ESCAPE I & II trials.[56,57] When compared to nitroglycerin, nitroprusside, and nicardipine in ECLIPSE trial, it showed comparable safety profile to them, and a significant reduction in mortality.[40] Indeed, it was more effective than nitroglycerin (P = 0.0006) and nitroprusside (P = 0.003) in maintaining BP within the predetermined range.[40] This agent was as effective as nicardipine, in maintaining BP within a predetermined range.[40] The VELOCITY trial showed a rapid and effective reduction in BP, with a decrease of 6% of BP within three minutes, 15% within 9.5 minutes and a 27% reduction in BP 18 hours after infusion initiation.[58] Clevidipine does not induce a reflex increase in heart rate. It has coronary vasodilatory properties.[53] These anti ischemic properties make clevidipine one of the best options for elderly patients presenting with hypertensive crises.

5.6 Labetalol

Labetalol is a combined α1-adrenergic and β-adrenergic receptors blocker, with greater effect on β-receptors as compared to α-receptors.[1] Labetalol can be administered either as a bolus or continuous infusion.[59] It has negative chronotropic and inotropic effects, which made it one of the preferred agents in the management of hypertensive crises in acute aortic dissection.[16,23] Labetalol was compared with nicardipine in the CLUE trial; and results showed that nicardipine is more likely than labetalol to achieve target blood pressure within 30 minutes.[60] Reported side effects include hypotension, bradycardia nausea, vomiting, scalp tingling, and burning sensation in the groin.[61] In elderly, labetalol’s side effects are even more significant, mainly due to delayed clearance of the agent in elderly.[62]

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