Agents for BP Lowering
The ideal agent for BP lowering is one that is well tolerated and easily titratable to achieve and maintain a desired BP target without excessive BP variability, and with minimal influence on cerebral vasodilation and hemostasis that might enhance ongoing hemorrhage. However, there are regional differences in the availability of intravenous BP lowering agents: nicardapine (calcium channel blocker) is favored in North America, whereas urapidil (α-adrenoreceptor blocker) is popular in China. Other agents include adrenoreceptor blockers (labetalol and metoprolol), other calcium channel blockers (nimodipine), nitrates, diuretics, renin-angiotensin system blockers, hydralazine, and nitroprusside. There may be heterogeneity in the effects (and safety) of various BP lowering agents, according to those most frequently used in the treatment group of 16 RCTs in the IPD meta-analysis. Patients who received α- and β-adrenoreceptor blockers appeared to have better outcomes from active/intensive BP lowering, compared with patients who had renin-angiotensin system blockers, calcium channel blockers, nitrates, and magnesium sulfate. These findings suggest that α- and β-adrenoreceptor blockers may benefit from blocking the autonomic response that has been shown to drive the hypertensive response from critical illness. However, further research is required to substantiate these findings.
Class I evidence exists for the use of nimodipine, an L-type calcium channel antagonist, in patients with SAH, which improves clinical outcome by reducing the risk of DCI. An important consideration, aside from its beneficial effect, are its BP lowering effects, of which significantly lowering diastolic BP (>20% from baseline) alone is associated with unfavorable outcome in acute ischemic stroke. Some authors, therefore, favor combining nimodipine with vasopressors in patients after aneurysm occlusion for SAH. Interestingly, the safety of nimodipine in ICH was shown in a small comparative study, where a reduction in ICP was seen during its administration but not afterwards.
Stroke. 2022;53(4):1065-1073. © 2022 American Heart Association, Inc.