ISSN:1075-2765    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;A randomized, double-blind, placebo-controlled clinical trial showed 14 of 18 (78%) of the elderly hypertensive men in this study had an uncomplicated and beneficial response to either fosinopril or verapamil. There was a well-tolerated reduction in systolic blood pressure (SBP) and diastolic blood pressure (DRP). There were no significant adverse drug events. Only the sitting SBP and the sitting DBP were significantly lowered by fosinopril and verapamil SR. Because reduction in both SBP and DBP in elderly hypertensives has been shown to be beneficial, these findings take on further importance when considering the choice of medication for antihypertensive therapy in the elderly. The increase in norepinephrine in the fosinopril-treated patients may explain why patients treated with long-term angiotensin-converting enzyme inhibitors alone or in combination with diuretics rarely complain of orthostatic symptoms.

ISSN:1075-2765    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;The effects of temperature on binding characteristics of phenytoin (PHT) to serum proteins were determined in adult patients with epilepsy. Serum samples examined in the study were obtained from 47 adult patients (29 men, 18 women) with epilepsy on PHT monotherapy. Ages ranged from 18 to 64 years (mean [SD], 36.8 [12.1] years). Protein binding of PHT was evaluated by ultrafiltration under current laboratory routine conditions (25 ± 3°C) or at a temperature of 37°C. The in vivo binding parameters of PHT to serum proteins were determined using a binding equation derived from the Scatchard equation for a one-site binding model. Significant differences were observed in serum concentrations of unbound PHT between paired data (P< .05). The mean association constants (K) of PHT to serum proteins are 0.009 L &mgr;mol−1at 25 ± 3°C and 0.003 L &mgr;mol−1at 37°C, whereas mean total concentrations of binding sites [n(Pt)] are 1215 &mgr;mol L−1for 25 ± 3°C and 2263 &mgr;mol L−1for 37°C. Significant differences were observed in binding characteristics of PHT to serum proteins between the data determined in different conditions of ultrafiltration (P< .05). Our study confirms that binding affinity for PHT-serum protein interaction is approximately 67% lower at 37°C than at 25 ± 3°C, and, consequently, binding potential [K •n(Pt)] is approximately 38% lower at 37°C than at 25 ± 3°C.

ISSN:1075-2765    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;The objective of this study was to assess the safety and efficacy of long-acting preparations of two commonly used calcium antagonists with particular reference to their effects on heart rate. Twenty patients with chronic stable angina were recruited to a double-blind, double-dummy crossover study of controlled-release diltiazem (diltiazem CR) versus sustained-release nifedipine (nifedipine SR) and underwent clinical assessment, symptom and adverse event reporting, and repeated treadmill exercise tests over a 10- to 11-week period. The main outcome measures were heart rate at rest and exercise, incidence of angina and nitroglycerin use, treadmill exercise performance (duration, time to angina, time to 1-mm ST-segment depression, heart rate at equivalent maximal exercise, and maximal ST-segment depression), and adverse events. Diltiazem CR significantly reduced heart rate at rest and equivalent exercise and incidence of angina and nitroglycerin use compared with nifedipine SR. Exercise duration time to angina and time to 1-mm ST-segment depression (but not maximal ST-segment depression) were all significantly improved by diltiazem CR. Diltiazem CR also caused significantly fewer adverse events than nifedipine SR. Calcium antagonists with negative chronotropic effects (eg, diltiazem CR) are safer and more efficacious as monotherapy in chronic stable angina than dihydropyridines (eg, nifedipine SR) even when a long-acting formulation of the latter is used.

ISSN:1075-2765    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;Perioperative hyponatremia has been recognized as a serious in-hospital complication for many years. Because the kidney responds to changes in extracellular fluid tonicity by adjusting water excretion, a defect in any of several key elements of water excretion can lead to water retention and hyponatremia. Most cases of hyponatremia are caused by impaired renal water excretion in the presence of continued water intake.For the kidney to excrete excess free water and thereby protect the extracellular fluid against hyponatremia, there must be an adequate glomerular filtration rate (GFR), adequate delivery of glomerular filtrate to the diluting segments of the distal nephron, intact tubular diluting mechanisms, and appropriate inhibition of antidiuretic hormone (ADH) synthesis and release. Virtually all of the clinical disorders producing hyponatremia are based on abnormalities of these few mechanisms of water regulation. Finding the reason for impaired renal water excretion is the key to diagnosing the cause of hyponatremia. Impaired renal water excretion may be caused by impaired GFR (renal failure), impaired water delivery to the diluting segments of the distal nephron because of increased proximal reabsorption (decreased extracellular fluid volume and edematous states), impaired renal diluting mechanism (thiazide diuretics), the syndrome of inappropriate ADH (SI-ADH) due to a variety of causes including the perioperative state, and hypothyroidism or adrenal insufficiency.Any of the states that impair water excretion can produce hyponatremia in a patient with an initially normal serum sodium concentration if sufficient free water is supplied. Therefore, a patient who has one of the conditions listed above, including the perioperative state, may be considered “water intolerant” even if the serum sodium is normal. Such a patient is at risk for developing severe hyponatremia if given hypotonic IV fluids or a large oral water load. An understanding of the basic mechanisms leading to impaired water excretion and “water intolerance” is therefore an important key to avoiding perioperative hyponatremia.

ISSN:1075-2765    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;Chronic pain is both difficult for patients to tolerate and for clinicians to treat effectively. It differs from other types of pain in etiology and impact, which in turn affects the duration and modalities of treatment options. Forty years of research have confirmed the efficacy of antidepressant agents in the management of chronic pain, yet these agents are used inadequately. A significant amount of evidence supports the use of the traditional tricyclic antidepressants (TCAs) in the management of chronic pain, but because of their acute synaptic effects on multiple, nontherapeutic receptor systems, they are associated with numerous undesirable side effects. The newer selective serotonin reuptake inhibitors (SSRIs) have, comparatively, only serotonin-receptor-mediated side effects. These agents have not been thoroughly studied in the treatment of chronic pain. Moreover, because SSRIs impact reuptake of only one monoamine system, it is plausible that they may be less efficacious than the TCAs in treating chronic pain. Venlafaxine, the first agent in the new class of serotonin (5-HT)-norepinephrine (NE) reuptake inhibitors, is unique because it inhibits reuptake of both 5-HT and NE (and to a lesser extent dopamine), as do some of the TCAs; however, it accomplishes this without affecting other nontherapeutic receptors. Venlafaxine is at least as effective as the TCAs, but is more tolerable, because it lacks the receptor-mediated side effects common to the TCAs. The unique characteristics of venlafaxine, including minimal cytochrome P-450 drug interaction, may make it a particularly useful antidepressant in the adjunctive treatment of chronic pain.

ISSN:1075-2765    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:1075-2765    

出版商:OVID    

年代:2000

数据来源: OVID