Acute hypertension

Inhaled NO has been used for treatment of persistent pulmonary hypertension of newborn infants, critical respiratory failure of preterm infants, and acute hypertension of adult cardiac surgery patients. PDE-5 inhibitors such as sildenafil are also effective for treatment of pulmonary hypertension. The combination of PDE-5 and NO inhalation yields additive beneficial effects on pulmonary hemodynamics. On the other hand, measurement of exhaled NO is a noninvasive and reproducible test that is a surrogate measure of airway inflammation in patients with bronchial asthma. 

A dramatic example of photolysis is the photodegradation of sodium nitroprusside in aqueous solution. Sodium nitroprusside, Na2Fe(CN)5NO-2 H20, is administered by intravenous infusion for the management of acute hypertension. If the solution is protected from light it is stable for at least one year if exposed to normal room light, it has a shelf life of only 4 hours [35]. 

The nitrovasodilator sodium nitroprusside (SNP) has been used for decades to manage acute hypertensive crises and congestive heart failure complicating myocardial ischemia [99]. However, prolonged SNP administration is limited by tolerance, the... 

When treating acute hypertensive episodes in patients with chronic hypertension, discontinuation of infusion is followed by a 50% offset of action in 30 minutes but plasma levels of drug and gradually decreasing antihypertensive effects exist for about 50 hours. 

Methyidopate hydrochloride may be used to initiate treatment of acute hypertensive crises however, due to its slow onset of action, other agents may be preferred for rapid reduction of blood pressure. 

Phenylephrine Acute venoconstriction acute hypertensive effect o... 

Excessive doses may cause acute hypertension or arrhythmias. 

Aronson S et al The ECLIPSE trials Comparative studies of clevidipine to nitroglycerin, sodium nitroprusside, and nicardipine for acute hypertension in cardiac surgery patients. Anesth Alang 2008 107 1110. [PMID 18806012]... 

Increased norepinephrine stored in adrenergic neuron. Displacement of these stores by other drugs may produce acute hypertensive response. MAOIs have intrinsic hypoglycemic activity. 

Sixteen different substances are known or have been found in body fluids or modifications of them, which either cause acute hypertension or lead to vasoconstriction in the experimental animal (Table I). Three of these substances are proteins, three peptides, six amines, two nicotinelike bases, and one steroid. Other unidentified substances have been detected. The prodigality of Nature in providing so many substances which act in... 

The renal pressor mechanism—renin and hypertensin—acts in acute hypertension and in acute renal ischemic states, but apparently not in chronic hypertension. The other mechanisms shown to be active in chronic hypertension are vasoexcitor-vasodepres-sor material relationship pherentasin, a pressor substance found only in human hypertension amines resulting from the insufficient oxidation of amino acids, which are increased in human hypertension and norepinephrine (Sympathin E), which largely reproduces the hemodynamic picture of chronic hypertension. Most of the known pressor substances, with the notable exception of norepinephrine, come from disturbances of, or are extracted from, the kidneys. The large number of pressor substances which have been obtained suggests that many may represent different stages of metabolism of certain parent substances, and that their effectors may be fewer in number and simpler in structure. The chemical identification and purification of most of these substances leave much to be desired, and their phafmacology has in most cases been inadequately studied. The whole problem, however, may soon become simplified. 

Xu, Q., Y. Liu, M. Gorospe, R. Udelsman, and NJ. Holbrook. 1996. Acute hypertension activates mitogen-activated protein kinases in arterial wall 2. J. Clin. Invest. 97 508-514. 

A pre-eclampsia-like syndrome has been described, characterized by acute hypertension and a low platelet count, in a 33-year-old cocaine user her 20-week-old fetus died (246). 

Powers WJ (1993). Acute hypertension after stroke the scientific basis for treatment decisions. Neurology 43 461-467... 

Systemic Effects. Ocular administration of phenylephrine has been reported to induce acute hypertension (see Table 8-2). Sixty patients were studied after three applications of the 10% solution in each eye at 10-minute intervals.Thirty minutes after the last drop, systolic elevations of 10 to 40 mm Hg and diastolic elevations of 10 to 30 mm Hg occurred in all subjects. In each case pulse rate decreased 10 to 20 beats per minute. In contrast to these observations, however, other investigators reported a lack of systemic vasopressor response with the 10% concentration. 

A 39-year-old quadriplegic man with poorly controlled pain had many features consistent with autonomic dysfunction (for example a C4 spinal lesion, orthostatic hypotension, hypertension). He routinely used trans-dermal clonidine and transdermal glyceryl trinitrate as needed for control of acute hypertensive episodes. The clonidine was discontinued, after which his blood pressure fell (maximum systolic and diastolic pressures by about 50 and 25 mmHg respectively). 

Acute hypertensive encephalopathy has occurred in a patient given methylergotamine (SEDA-3, 121). 

Three cases of severe hjrperkalemia have been reported in renal transplant recipients taking labetalol for acute hypertension (6) and life-threatening hyperkalemia has been reported after intravenous labetalol (7). 

Arthur S, Greenberg A. Hyperkalemia associated with intravenous labetalol therapy for acute hypertension in renal transplant recipients. Clin Nephrol 1990 33(6) 269-71. 

Metaraminol (2-10 mg intramuscularly) is used to treat serious hypotension. It has no noticeable central nervous effects and the beta-adrenoceptors of the heart usually do not react. The maximum effect of a dose is not at once apparent, and one should wait for some 10 minutes before deciding to give a further dose. In two patients an intravenous infusion of metaraminol to treat paroxysmal supraventricular tachycardia resulted in acute hypertension and pulmonary edema (1). Subcutaneous administration is risky and can result in dangerous sloughing. 

Goldberg J, Moreno F, Barbara J. Acute hypertension as an adverse effect of pyrazinamide. JAMA 1997 277(17) 1356. 

LysonT, McMullan DM, Ermel LD, Morgan BJ, Victor RG. Mechanism of cyclosporine-induced sympathetic activation and acute hypertension in rats. Hypertension 1994 23 667-675. 

Benetos A, Bresnahan M, Gavras I, Gavras H. Central catecholamines and a adrenoceptors in acute hypertension induced by intracerebroventricular hypertonic saline. J Hypertens 1987 5 699-704. 

Administration of nitroprusside to control acute hypertension contributes to the total body pool of CN" and complicates the interpretation of the blood CN" concentration. Nitroprusside (Fe[CN]5NO) avidly binds to hemoglobin in erythrocytes at equilibrium, the amount of CN" that is bound in the erythrocyte owing to nitroprusside as com-... 

OTC cold medications, or other medications that contain drugs with a, agonist activity (e.g., ephedrine, phenylpropanolamine), should be avoided with P antagonist therapy, as they may precipitate acute hypertension. This is due to the vasoconstrictor actions of the a agonist that are unopposed in the presence of a drug with P2 antagonist activity. 

Only mecamylamine (INVERSINE) is currently available in the U.S. Ganglionic blocking agents have been supplanted by superior agents for the treatment of chronic hypertension (see Chapter 32), acute hypertensive crises and the production of controlled hypotension (e.g., reduction in blood pressure during surgery to minimize hemorrhage in the operative field). 

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