enalaprilat-anhydrous and Brain-Ischemia

Hypertensive emergency is defined as a systolic blood pressure > 180 mmHg or a diastolic blood pressure > 120 mmHg with evidence of new or progressive end-organ damage. The purpose of this paper is to review advances in the treatment of hypertensive emergencies within the last 5 years.. New literature and recommendations for managing hypertensive emergencies in the setting of pregnancy, stroke, and heart failure have been published. Oral nifedipine is now considered an alternative first-line therapy, along with intravenous hydralazine and labetalol for women presenting with pre-eclampsia. Clevidipine is now endorsed by guidelines as a first-line treatment option for blood pressure reduction in acute ischemic stroke and may be considered for use in intracranial hemorrhage. Treatment of hypertensive heart failure remains challenging; clevidipine and enalaprilat can be considered for use in this population although data supporting their use remains limited.

Topics: Administration, Oral; Antihypertensive Agents; Blood Pressure; Brain Ischemia; Emergencies; Enalaprilat; Female; Guideline Adherence; Heart Failure; Humans; Hydralazine; Hypertension; Infusions, Intravenous; Intracranial Hemorrhages; Labetalol; Nifedipine; Pre-Eclampsia; Pregnancy; Pyridines; Stroke

Previous studies showed that angiotensin II (AII) infusion increased survival in gerbils subjected to abrupt unilateral carotid ligation. Recently, stimulation of the AII AT2 receptor, reportedly effectively extended the blood pressure (BP) range of cerebral blood flow (CBF) autoregulation. We evaluated the survival of gerbils treated with PD-123319, a ligand of AT2 receptors, to test the hypothesis that restoration of BF to ischemic cerebral tissue produced by AII is mediated through AT2 receptors. Abrupt unilateral carotid ligation was performed on 300 gerbils. In five experimental groups, animals received no drug pretreatment: (a) saline; (b)-(d) PD-123319 1.0, 3.0, and 10 mg/kg; and (e) losartan 10 mg/kg. In three additional experimental groups, animals were pretreated with enalaprilat: (f) saline; (g) PD-123319, 10 mg/kg, and (h) losartan, 10 mg/kg. Survival for 48 h was significantly improved by PD-123319 (10 mg/kg) (p < 0.05) and by losartan (10 mg/kg) (p < 0.05) as compared with animals injected with saline. Pretreatment with enalaprilat neutralized the protective effect of losartan. PD-123319 is an AT2 agonist and improved survival in this animal model of stroke. Losartan, an AT1 antagonist, also improved survival, possibly through renin release and AT2 stimulation by endogenous AII. This effect was neutralized by enalaprilat.

Topics: Animals; Biphenyl Compounds; Brain Ischemia; Carotid Arteries; Dose-Response Relationship, Drug; Drug Interactions; Enalaprilat; Gerbillinae; Imidazoles; Ligation; Losartan; Male; Pyridines; Receptors, Angiotensin; Regional Blood Flow; Survival Analysis; Tetrazoles