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Query: UMLS:C0010200 (cough)
 23,843 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Candesartan is a highly potent, long-acting and selective angiotensin II type 1 (AT1) receptor blocker. It is administered orally as the inactive prodrug candesartan cilexetil which is rapidly and completely converted to candesartan during gastrointestinal absorption. In vitro studies have shown that candesartan acts as an insurmountable angiotensin II receptor antagonist, binding tightly to and dissociating slowly from the AT1 receptor. The above characteristics are thought to contribute to the marked and long-lasting antihypertensive effects of candesartan cilexetil in several animal models of hypertension. These included rodent models of renal hypertension in which candesartan cilexetil also demonstrated efficacy equivalent to or greater than enalapril. In other animal models, candesartan cilexetil reduced the incidence of stroke, renal dysfunction and renal disease while reducing cardiac and vascular hypertrophy. Furthermore, candesartan cilexetil conferred some protection against cerebral and renal damage at a dose that had no blood pressure-lowering effect. In toxicity and general pharmacology studies, candesartan cilexetil was shown to possess a 'clean' profile with a large safety margin. Also it did not potentiate chemical- or autocoid-induced cough or anaphylactoid reactions.
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PMID:Candesartan cilexetil: a review of its preclinical pharmacology. 933 Sep 99

Losartan is a novel orally active nonpeptidal antihypertensive agent that specifically blocks the angiotensin II type 1 receptor. This paper compares the short- and long-term safety and tolerability of losartan with those of placebo. Approximately 3800 patients with mild-to-severe essential hypertension were enrolled in 16 double-masked and 4 open clinical trials worldwide. Of these, approximately 2900 were treated with losartan either alone or in combination with other antihypertensive drugs. These trials included patients with diabetes mellitus (n = 133). An additional 5 trials enrolled hypertensive patients with compromised renal function (n = 115) or heart failure (n = 220). Losartan dosages primarily ranged from 10 to 150 mg once daily, with most patients receiving 50 to 100 mg per day. Hypertension trials generally lasted 12 weeks. The most frequently reported adverse events were headache, upper respiratory tract infection, dizziness, and asthenia/fatigue, but only dizziness occurred more frequently (> or = 1%) in the losartan-treated groups. Cough occurred in 3.1% of patients treated with losartan and 2.6% of patients treated with placebo. The overall incidence of clinical and laboratory adverse events in the losartan- and placebo-treated groups was similar among patients with hypertension and either diabetes mellitus, renal impairment, or heart failure. The data suggest that losartan can be safely administered in hypertensive patients with concomitant illnesses. It can be considered for first-line therapy and is suitable as an alternative therapy in patients already experiencing side effects with other agents.
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PMID:Clinical safety and tolerability of losartan. 937 6

The octapeptide hormone, angiotensin II, binds to two major subtypes of cell surface receptors: the AT1 and the AT2 angiotensin receptors. The important physiological and pathophysiological effects of angiotensin II on cardiovascular regulation and salt-water balance are mediated by the AT1 receptor subtype. As a consequence of the outstanding clinical success of angiotensin-converting enzyme inhibitors, the appearance of AT1 receptor inhibitors in the therapy of hypertension and other cardiovascular diseases was preceded with great expectations. The available experimental and clinical data indicate that the first AT1 receptor inhibitor, losartan, has the same therapeutic potential as angiotensin-converting enzyme inhibitors, but it does not evoke the angiotensin-independent side-effects of ACE inhibitors, such as dry cough or angioedema. The physiological importance and the biochemical, molecular biological and pharmacological properties of AT1 and AT2 receptors are reviewed in this paper, and a summary of the available clinical data is presented.
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PMID:[AT1 angiotensin receptor inhibition as a new therapeutic possibility]. 941 27

The rationale behind combination therapy relates to the fact that when two different classes of agents are combined, they may provide complementary, additive, or synergistic antihypertensive effects through different mechanisms. Lower doses of two drugs, which provide blood pressure reduction similar to higher doses of one drug, may enhance tolerability and improve compliance. Investigative efforts have been undertaken to explore fixed-dose combinations of drugs that do not include diuretics. The first nondiuretic fixed-dose combinations are an angiotensin-converting enzyme (ACE) inhibitor-calcium antagonist combination or a beta-blocker-calcium antagonist combination. The rationale for an ACE inhibitor-calcium antagonist combination is based on the fact that both drugs reduce vasoconstriction through different mechanisms. The ACE inhibitor largely attenuates vasoconstriction through augmentation of vasodilatory kinins and reduction of the vasoconstrictive effect of angiotensin II, whereas the calcium antagonists, through attenuating the transmembrane flux of calcium, inhibit calcium-mediated electromechanical coupling in contractile tissue in response to numerous stimuli. Moreover, both classes of drugs facilitate salt and water excretion by the kidney through different mechanisms. The ACE inhibitor restores the renal-adrenal response to salt loading, whereas the calcium antagonist possesses intrinsic natriuretic properties through poorly described mechanisms of inhibiting renal tubular salt and water reabsorption. The combination of a beta-blocker and dihydropyridine calcium antagonist is logical due to the different antihypertensive mechanisms of these drugs without risk of cardiac conduction abnormalities. There is evidence in clinical trials that ACE inhibitors may offset one of the major side effects associated with calcium antagonist therapy: pedal edema. Although the studies are small and the observations subjective, there is consistent evidence that the combination may provide an opportunity to reduce the likelihood of this common clinical problem. There is also evidence of reduced calcium antagonist-associated constipation and headache with this type of drug combination, likely because lower doses of this agent are used in combination with ACE inhibitors. However, there is no published evidence that calcium antagonists reduce the cough associated with the ACE inhibitor.
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PMID:The rationale for combination versus single-entity therapy in hypertension. 979 51

The objective of this study was to determine the incidence of dry cough in hypertensive patients with a history of angiotensin-converting enzyme (ACE) inhibitor-induced cough after treatment with losartan (an angiotensin II-receptor antagonist), lisinopril (an ACE inhibitor), or placebo. One hundred patients from 16 outpatient treatment centers in the United States were included in this double-masked, randomized, parallel-group, active- and placebo-controlled study, with stratification according to sex. After a challenge phase with lisinopril and a placebo washout phase, patients were randomly allocated to receive losartan 50 mg once daily, lisinopril 20 mg once daily, or placebo for a maximum of 8 weeks. The primary efficacy end point of the study was the presence or absence of dry cough during the double-masked period, as rated by the patient at each visit using a validated symptom assessment questionnaire. A secondary end point was the frequency of dry cough, as measured at each visit using a visual analogue scale (VAS). The incidence of dry cough was significantly higher in the lisinopril group than in the losartan and placebo groups (87.5% vs 36.7% and 31.4%, respectively) at the end of the double-masked treatment period; there was no statistically significant difference between the losartan and placebo groups. Mean VAS scores showed that patients treated with lisinopril rated themselves as having a significantly higher frequency of cough than did patients treated with losartan or placebo (4.0 vs 1.2 and 1.5, respectively). Again, the difference between the losartan and placebo groups was not statistically significant. All treatments were otherwise well tolerated, and no serious clinical or laboratory adverse events were reported during the double-masked phase of the study. These results demonstrate that the incidence, severity, and frequency of dry cough in patients with a history of ACE inhibitor-induced dry cough are significantly lower in those treated with losartan than in those treated with lisinopril and are similar to the incidence, severity, and frequency of dry cough in those receiving placebo.
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PMID:Use of losartan in the treatment of hypertensive patients with a history of cough induced by angiotensin-converting enzyme inhibitors. 982 49

Tolerability and not efficacy is the limiting factor for long-term successful antihypertensive treatment. Since the discontinuation rate of first line antihypertensives may be as high as 50-60% over six months, it is important to develop new agents with an improved efficacy/tolerability ratio. Candesartan cilexetil is particularly promising in this respect. Candesartan is a potent and selective angiotensin II type 1 (AT1) receptor blocker that binds selectively and tightly (insumontable binding) to the receptor. Candesartan is not associated with any increased risk of cough or angiodema. It is an orally effective vasodilator that does not cause reflex tachycardia or first dose hypotension or orthostatic hypotension. In the dose range from 4-16 mg, once daily candesartan cilexetil is not associated with any dose-dependent adverse events and it is equally well tolerated in men and women and by older (> 65 years) and younger (< 65 years) patients. Furthermore, the drug has no adverse effect on glucose homeostasis or plasma lipid profile. In a double-blind comparison with losartan 50 mg od, candesartan cilexetil 16 mg once daily was significantly more effective in lowering the diastolic blood pressure at the end of the 24 h dose interval but was equally well tolerated. In meta-analyses of clinical trials, candesartan cilexetil showed a tolerability profile comparable to that of placebo therapy.
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PMID:Tolerability of a modern antihypertensive agent: candesartan cilexetil. 983 64

Clinical trials of candesartan cilexetil conducted in Japan are reviewed. Candesartan cilexetil inhibited the pressor response to intravenous angiotensin II in healthy volunteers, with peak effects observed at 4 or 8 h after oral dosing; suppressing effects persisted up to 24 h. In 14 multicentre studies with 928 hypertensive patients treated for 8 to 12 weeks, candesartan cilexetil had an efficacy rate (reduction of systolic/diastolic blood pressure > or = 20/10 mm Hg and/or mean blood pressure > or = 13 mm Hg) of 72% and 63%, and an adverse effect rate of 9.9% and 7.3%, in patients with mild-to-moderate essential hypertension and those with impaired renal function, respectively. When data for elderly patients were analysed, there was no difference in efficacy and tolerability compared to non-elderly patients. In a double-blind comparative study, candesartan cilexetil was superior to enalapril in hypertensive patients: efficacy rate, 74% vs 66% (NS); adverse symptom rate, 10.4% vs 27.3% (P < 0.01); incidence of cough, 1.5% vs 14.8% (P < 0.01). Treatment with 2-8 mg of candesartan cilexetil once daily for 8 to 12 weeks reduced the left ventricular mass index without deterioration of cardiac function. In conclusion, 4-12 mg of candesartan cilexetil once daily is effective and well tolerated in patients with essential hypertension, including elderly patients, those with severe hypertension, and hypertensive patients with renal insufficiency. Its improved tolerability profile over angiotensin-converting enzyme inhibitors, as well as its end-organ protective effects, suggest that candesartan cilexetil is useful as a first-line antihypertensive drug.
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PMID:Clinical efficacy and tolerability of candesartan cilexetil. Candesartan Study Groups in Japan. 1007 18

The renin-angiotensin-aldosterone system (RAAS) plays an important role in both the short-term and long-term regulation of arterial blood pressure, and fluid and electrolyte balance. The RAAS is a dual hormone system, serving as both a circulating and a local tissue hormone system (i.e., local mediator) as well as neurotransmitter or neuromediator functions in CNS. Control of blood pressure by the RAAS is exerted through multiple actions of angiotensin II, a small peptide which is a potent vasoconstrictor hormone implicated in the genesis and maintenance of hypertension. Hypertension is a primary risk factor associated with cardiovascular, cerebral and renal vascular disease. One of the approaches to the treatment of hypertension, which may be considered as a major scientific advancement, involves the use of drugs affecting the RAAS. Pharmacological interruption of the RAAS was initially employed in the late 1970s with the advent of the angiotensin converting enzyme (ACE) inhibitor, captopril. ACE inhibitors have since gained widespread use in the treatment of mild to moderate hypertension, congestive heart failure, myocardial infarction, and diabetic nephropathy. As the roles of the RAAS in the pathophysiology of several diseases was explored, so did the realization of the importance of inhibiting the actions of angiotensin II. Although ACE inhibitors are well tolerated, they are also involved in the activation of bradykinin, enkephalins, and other biologically active peptides. These actions result in adverse effects such as cough, increased bronchial reactivity, and angioedema. Thus, the goal of achieving a more specific blockade of the effects of angiotensin II than is possible with ACE inhibition. The introduction of the nonpeptide angiotensin II receptor antagonist losartan in 1995 marked the achievement of this objective and has opened new vistas in understanding and controlling the additional biological effects of angiotensin II. Complementary investigations into the cloning and sequencing of angiotensin II receptors have demonstrated the existence of a family of angiotensin II receptor subtypes. Two major types of angiotensin II receptors have been identified in humans. The type 1 receptor (AT1) mediates most known effects of angiotensin II. The type 2 receptor (AT2), for which no precise function was known in the past, has gained importance recently and new mechanisms of intracellular signalling have been proposed. This review presents recent advances in angiotensin II receptor pharmacology, molecular biology, and signal transduction, with particular reference to the AT1 receptor. Excellent reviews have appeared recently on this subject.
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PMID:Angiotensin II receptors-antagonists, molecular biology, and signal transduction. 1009 99

Hypertension occurs frequently in patients with renal disease and contributes to the development of end-stage renal disease. Because the renin angiotensin system (RAS) influences hypertension and renal disease, angiotensin-converting enzyme (ACE) inhibitors have been used successfully to treat and reduce renal consequences of hypertension. This review assesses how angiotensin II (A-II) influences renal disease and explores the effectiveness of losartan, a selective A-II receptor blocker, in patients with renal disease. Clinical trials have demonstrated that losartan is a safe and effective treatment for hypertension in renally impaired patients and produces renal hemodynamic effects akin to those seen with ACE inhibitors. However, losartan demonstrates a greater uricosuric effect than ACE inhibitors and does not produce cough, a significant side effect frequently associated with ACE inhibitors. Further studies will determine whether combination therapy with an ACE inhibitor and A-II receptor blocker will provide additional RAS blockade and synergistic benefits in patients with renal disease.
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PMID:The benefits of angiotensin II receptor blockers in patients with renal insufficiency or failure. 1009 45

One possible intervention to interrupt the deleterious effects of the renin-angiotensin system is suppression of angiotensin II (Ang II) formation by inhibition of angiotensin-converting enzyme (ACE). However, ACE inhibition incompletely suppresses Ang II formation and also leads to accumulation of bradykinin. Angiotensin II type 1 (AT1) receptors are believed to promote the known deleterious effects of Ang II. Therefore, AT1 receptor antagonists have been recently introduced into therapy for hypertension and congestive heart failure (CHF). Although there are significant differences between the effects of AT1 receptor antagonists and ACE inhibitors including the unopposed stimulation of angiotensin II type 2 (AT2) receptors by AT1 receptor antagonists, the discussion of whether ACE inhibitors, AT1 receptor antagonists or the combination of both are superior in the pharmacotherapy of CHF is still largely theoretical. Accordingly, AT1 receptor antagonists are still investigational. Angiotensin-converting enzyme inhibitors remain first line therapy in patients with CHF due to systolic dysfunction. However, in patients not able to tolerate ACE inhibitor induced side effects, in particular cough, AT1 receptor antagonism is a good alternative. In clinical practice, emphasis should be placed on increasing the utilization of ACE inhibitors, as more than 50% of patients with CHF do not receive ACE inhibitors. In addition, the majority of those on ACE inhibitors receive doses lower than the dosage used in the large clinical trials. Although not yet completely proved, it is likely that high doses of ACE inhibition are superior to low doses with respect to prognosis and symptoms.
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PMID:Recent insight into therapy of congestive heart failure: focus on ACE inhibition and angiotensin-II antagonism. 1019 12


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