Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Careful consideration of absolute and relative contraindications, including newly appreciated factors such as past pregnancy-related hypertension, is essential to select what is termed the "safer women." A family history of either arterial or venous thrombosis indicates preliminary blood analysis to exclude atherogenic lipid states and thrombophilias. The goal then is to prescribe "safer pills." One should also allow for biologic variation in pharmacokinetics and end-organ responses. This can be done to a limited extent in clinical practice by using bleeding from the uterus as a "threshold bioassay." Namely, by identifying for each woman the lowest dose of a chosen estrogen-progestogen combination that is just sufficient to prevent breakthrough bleeding. Thereafter, monitoring requires attention to the development of new risk factors, regular blood pressure checks, and specific attention to the important side effects of headaches and migraines, especially if there are focal (cerebral ischemic) symptoms.
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PMID:Oral contraceptives in risk groups: exclusion or monitoring? 219 13

Autoregulation of blood flow denotes the intrinsic ability of an organ or a vascular bed to maintain a constant perfusion in the face of blood pressure changes. Alternatively, autoregulation can be defined in terms of vascular resistance changes or simply arteriolar caliber changes as blood pressure or perfusion pressure varies. While known in almost any vascular bed, autoregulation and its disturbance by disease has attracted particular attention in the cerebrovascular field. The basic mechanism of autoregulation of cerebral blood flow (CBF) is controversial. Most likely, the autoregulatory vessel caliber changes are mediated by an interplay between myogenic and metabolic mechanisms. Influence of perivascular nerves and most recently the vascular endothelium has also been the subject of intense investigation. CBF autoregulation typically operates between mean blood pressures of the order of 60 and 150 mm Hg. These limits are not entirely fixed but can be modulated by sympathetic nervous activity, the vascular renin-angiotensin system, and any factor (notably changes in arterial carbon dioxide tension) that decreases or increases CBF. Disease states of the brain may impair or abolish CBF autoregulation. Thus, autoregulation is lost in severe head injury or acute ischemic stroke, leaving surviving brain tissue unprotected against the potentially harmful effect of blood pressure changes. Likewise, autoregulation may be lost in the surroundings of a space-occupying brain lesion, be it a tumor or a hematoma. In many such disease states, autoregulation may be regained by hyperventilatory hypocapnia. Autoregulation may also be impaired in neonatal brain asphyxia and infections of the central nervous system, but appears to be intact in spreading depression and migraine, despite impairment of chemical and metabolic control of CBF. In chronic hypertension, the limits of autoregulation are shifted toward high blood pressure. Acute hypertensive encephalopathy, on the other hand, is thought to be due to autoregulatory failure at very high pressure. In long-term diabetes mellitus there may be chronic impairment of CBF autoregulation, probably due to diabetic microangiopathy.
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PMID:Cerebral autoregulation. 220 48

The authors have studied 30 patients with transient global amnesia aged between 49 and 76 years (median age of 63 years), without focal neurologic signs that have been followed for periods varying between 6 months and 10 years. Three of the patients had recurrent attacks of transient global amnesia, and another three had a stroke, although at some distance from the amnesia attack. Association was noted with certain risk factors including high blood pressure, and angiopathic changes of the eye fundus (in 50% of the patients), dyslipidemia (in 30%), diabetes (in 10%), and essential polyglobulia (in 7%). Coagulation studies including thrombelastograms were carried out in 22 patients, and demonstrated hypercoagulability in 50% of them. Changes in the arterial wall were noted in 85% of the 14 patients in whom carotid sphygmograms were recorded. The presence of these risk factors could explain the occurrence of cerebrovascular accidents in patients with transient global amnesia. Electroencephalograms performed immediately or a short time after the amnesia attack have evidenced in 18 patients rapid-type dysrhythmia, or diffuse theta waves, predominantly located in the deep layers of the left and right temporal areas. The EEG tracings were either flat or normal in the remaining 12 patients. Of the 30 patients presenting with global transient amnesia only two had migraine in antecedents, and another six had headache during the evolution of amnesia. The neurologic examination did not reveal any abnormality in 27 of the patients. Sequelar signs of neurological deficits were noted in the remaining three patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Transient global amnesia (a study of 30 cases)]. 223 8

Strokes in young adults are uncommon and often a diagnostic challenge. A retrospective study of strokes due to intracerebral hemorrhage, subarachnoid hemorrhage, or cerebral infarction was undertaken. We reviewed the medical records of 113 young patients aged 15-45 years who were admitted to the Medical Center Hospital of Vermont with a diagnosis of stroke between 1982 and 1987. This group comprised 8.5% of patients of all ages admitted for stroke, 2.3 times the proportion observed in the National Survey of Stroke. Nontraumatic intracerebral hemorrhage was diagnosed in 46 young patients (41%); the main causes included aneurysms, arteriovenous malformations, hypertension, and tumors. Subarachnoid hemorrhage was found in 19 young patients (17%); the majority were due to aneurysms. The remaining 48 young patients (42%) had cerebral infarction, the majority due to cardiogenic emboli and premature atherosclerosis. Mitral valve prolapse, the use of oral contraceptives, alcohol drinking, and migraine were infrequent sole causes of cerebral infarction in the absence of other risk factors. The case-fatality rate for this group of young patients with stroke was 20.4% compared with 23.9% for the National Survey of Stroke. Young adults with stroke deserve an extensive but tailored evaluation, which should include angiography and echocardiography.
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PMID:Stroke in young adults. 230 61

The steady state pharmacokinetics of propranolol was examined in 48 Saudi Arabian patients chronically treated with oral doses [mean (SEM) = 85.8 (5) mg] of this drug. The mean (SEM) of the steady state concentration (Css) per mg/kg daily dose was 21.8 (3.1) ng.ml-1/mg.kg-1. A 6-fold variability in Css was observed between patients treated with 40 mg every 8 hours and 14-fold between patients treated with 40 mg twice daily. The frequency distribution of the apparent oral clearance (TCLor) of propranolol was bimodal with 88% of the patients showing TCLor of 18 to 372 l.hr-1 while the remainder had TCLor of 471 to 749 l.hr-1. The mean (SEM) of the TCLor per kg body weight for all 48 patients was 3.16 (0.38) l.hr-1.kg-1. Both Css and TCLor obtained for Saudi Arabian patients are not significantly different from those reported for subjects from Western populations. While Css increased proportionally (P less than .001) with dosing, a near-significant (P less than .06), inverse, linear relationship was found between age and TCLor. No significant effect of sex, body weight, or disease state (i.e., heart diseases, hypertension, depression, migraine) on Css or TCLor was detected.
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PMID:Steady state pharmacokinetics of propranolol in Saudi Arabian patients and comparison with data for different populations. 231 65

The correlation of specific headache attack characteristics derived from a standardized questionnaire was studied in a consecutive series of 392 patients attending a headache clinic. In patients reporting headache with aura such attacks tended to be infrequent, and the percentage of their headache attacks that were preceded by aura varied widely, many cases having very low percentages. Paresthesias as auras were uncommon and rarely occurred without visual aura. Unilateral headaches were associated with nausea to widely varying degrees. Most patients reported both unilateral headache and headache with tension characteristics. Definite history of hypertension was significantly correlated specifically with migraine with aura (classic migraine).
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PMID:Specific headache phenomena: their frequency and coincidence. 232 17

Calcium-channel blockers may well be the drugs of choice for treating angina, hypertension, and supraventricular arrhythmia in the elderly. They are effective, have no serious side effects, and when wisely matched to the patient, are very well tolerated. Most calcium-channel blockers can be administered once or twice daily. A choice of four is available; only verapamil and diltiazem hydrochloride are useful for supraventricular arrhythmia. All four, however, are effective for the treatment of hypertension and angina. Expanding uses of calcium-channel blockers include peripheral vascular disease and migraine. There may be a theoretical advantage in humans from the point of view of the anti-atherosclerosis demonstrated in animals.
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PMID:Calcium-channel blockers and the elderly. 237 3

A retrospective study was made of 309 randomly selected potential service recruits seen over five years by different consultant physicians in an Army hospital. Only nine of 133 referred with a history of asthma were turned down because of an abnormality in their exercise lung function test. Only four of 92 referred for a systolic heart murmur were rejected. Only one was turned down because of a headache or migraine out of 30 referred with that diagnosis. None of nine with supposed high blood pressure nor of five with a past history of pneumothorax was rejected. Of seven referred because of epilepsy, all five with definite evidence of this were turned down. The predictability of the specialist decision in these conditions suggests that more than 80% of all potential recruits referred to hospital with medical problems (at least 800 people yearly in UK) do not need to attend.
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PMID:Potential recruits in medical outpatients--an audit. 226 35

The mechanism of action of calcium channel modulators, a class of drugs that includes 3 chemical groups--1,4-dihydropyridines, phenylalkylamines and benzothiazepines--has been extensively reviewed. The best known representatives of these 3 groups are nifedipine, verapamil and diltiazem, respectively. These drugs bind reversibly, stereospecifically and with high affinity to both the membrane-bound and the purified receptor complex. Non-dihydropyridines allosterically regulate dihydropyridine binding. This has been shown by using (-) [3H]202-791 and (+) [3H]PN200-110 as labeled ligands. The purified receptor complex that possesses binding sites for all 3 chemical groups is likely to be related to the voltage-dependent calcium channel. As the result of a drug-receptor interaction, voltage-dependent calcium channels are either activated or inactivated. The drugs that activate channels act by promoting long-lasting channel openings. The drugs that inhibit calcium channels, the calcium entry-blocking agents, act by preventing channel openings upon membrane depolarization. A complex pharmacologic, electrophysiologic, biochemical, immunologic and molecular genetic approach is required to determine the molecular mechanism of action of calcium channel modulators. Clinically, calcium entry-blocking agents are recommended for the treatment of angina pectoris, hypertension, posthemorrhagic cerebral vasospasm, supraventricular tachycardia, migraine and asthma and the protection of the ischemic myocardium.
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PMID:Receptor pharmacology of calcium entry blocking agents. 243 27

The present article deals with the pathophysiological role of serotonin in cardiovascular disease and in other disorders that are accompanied by cardiovascular pathophysiological events. The distribution of serotonin over various organs and tissues and the presence of several types of 5-HT receptors would suggest a rather important physiological role of serotonin. However, a modest serotonergic role could only be shown for the microcirculation and for the regional circulation of the brain and the intestinal wall. An important pathological role of serotonin in the carcinoid syndrome, in migraine, and in peripheral vascular disease is beyond debate, although many details remain to be established. The possibility that serotonergic mechanisms contribute to Raynaud's phenomenon and other vasospastic disorders is the subject of present discussions, although firm evidence for this view is not widely available. An involvement of peripheral serotonin in the genesis and maintenance of essential hypertension seems very unlikely, although vascular damage due to hypertension is probably enhanced by serotonin released from aggregating platelets. This ancillary process is, in particular, to be anticipated in older patients, with vascular walls predamaged by atherosclerosis. For this reason, pharmacological blockade of 5-HT2 receptors may be of potential therapeutic benefit in this category of patient. Finally, the involvement of central serotonergic mechanisms in hypertensive disease cannot be ruled out.
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PMID:Pathophysiological relevance of serotonin. 244 63


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