Angiotensin-Converting Enzyme Inhibitor-Induced Cough

Unexplained cough in the adult

Unexplained cough is a diagnosis of exclusion that should not be made until a thorough validated diagnostic evaluation is performed, specific and appropriate validated treatments have been tried and failed, and uncommon causes have been ruled out. When chronic cough remains troublesome after the initial work up, determine that a protocol has been used that has been shown to lead to successful results. If such a protocol has been used, next consider whether or not pitfalls in management have been avoided. If they have been, the frequency of truly unexplained chronic cough usually should not exceed 10%. While patients with truly unexplained coughs have an overly sensitive cough reflex, the mere presence of an overly sensitive cough reflex does not by itself explain why they do not get better, because most patients with chronic cough, even those who respond to treatment and get better, have demonstrable heightened cough sensitivity. Management options include referral to a cough clinic with interdisciplinary expertise, speech therapy, and self-limited trials of drugs, preferentially with those shown to be effective in randomized, double-blind placebo-controlled trials in patients with unexplained chronic cough.

Problems of nonadherence in cardiology and proposals to improve outcomes

At least 1 in 7 cardiology patients now reports nonadherence to prescribed medications, potentially leading to negative outcomes across a broad range of cardiovascular diseases. This nonadherence can begin as early as the time of prescription or any time thereafter and occurs for a variety of reasons, including communication difficulties, polypharmacy, and a variety of objective and perceived side-effects. Among elderly, low-income, and disabled patients, drug costs represent a growing source of medication nonadherence and can be markedly reduced through the use of drug assistance programs and low-cost generic medications without sacrificing evidence-based therapy. Depression also contributes strongly to nonadherence and is widely prevalent in cardiovascular populations. Improvements in depression are mirrored by improvements in adherence. A systematic screening to identify the presence of nonadherence and many of its causes can be accomplished with minimal impact on visit length. In conclusion, once specific concerns are recognized, options frequently exist to help patients and providers address many of the most common difficulties.

Rhinorrhea, cough and fatigue in patients taking sitagliptin

Sitagliptin is a dipeptidyl peptidase-4 (DPP IV, CD26) inhibitor indicated for treatment of Type II diabetes as a second line therapy after metformin. We report fifteen sitagliptin intolerant patients who developed anterior and posterior rhinorrhea, cough, dyspnea, and fatigue. Symptoms typically developed within 1 to 8 weeks of starting, and resolved within 1 week of stopping the drug. Peak expiratory flow rates increased 34% in 8 patients who stopped sitagliptin. Similar changes were found in 4 out of 5 persons who had confirmatory readministration. Chart review identified 17 patients who tolerated sitagliptin and had no symptomatic changes. The sitagliptin intolerant group had higher rates of clinically diagnosed allergic rhinitis (15/15 vs. 6/18; p = 0.00005), Fisher's Exact test) and angiotensin converting enzyme inhibitor - induced cough (6/13 vs. 1/18; p = 0.012). Nasal and inhaled glucocorticoids may control the underlying allergic inflammation and abrogate this new sitagliptin - induced pharmacological syndrome. Potential mucosal and central nervous system mechanisms include disruption of neuropeptides and/or cytokines that rely on DPP IV for activation or inactivation, and T cell dysfunction.

CICADA: Cough in Children and Adults: Diagnosis and Assessment. Australian cough guidelines summary statement

Cough is a common and distressing symptom that results in significant health care costs from medical consultations and medication use. Cough is a reflex activity with elements of voluntary control that forms part of the somatosensory system involving visceral sensation, a reflex motor response and associated behavioural responses. At the initial assessment for chronic cough, the clinician should elicit any alarm symptoms that might indicate a serious underlying disease and identify whether there is a specific disease present that is associated with chronic cough. If the examination, chest x-ray and spirometry are normal, the most common diagnoses in ADULTS are asthma, rhinitis or gastro-oesophageal reflux disease (GORD). The most common diagnoses in CHILDREN are asthma and protracted bronchitis. Management of chronic cough involves addressing the common issues of environmental exposures and patient or parental concerns, then instituting specific therapy. In ADULTS, conditions that are associated with removable causes or respond well to specific treatment include protracted bacterial bronchitis, angiotensin-converting enzyme inhibitor use, asthma, GORD, obstructive sleep apnoea and eosinophilic bronchitis. In CHILDREN, diagnoses that are associated with removable causes or respond well to treatment are exposure to environmental tobacco smoke, protracted bronchitis, asthma, motor tic, habit and psychogenic cough. In ADULTS, refractory cough that persists after therapy is managed by empirical inhaled corticosteroid therapy and speech pathology techniques.

Choosing among renin-angiotensin system blockers for the management of hypertension: from pharmacology to clinical efficacy

BACKGROUND

Hypertension is an important healthcare challenge, yet despite initiatives to improve detection and advances in therapy, the majority of patients do not achieve recommended blood pressure targets and remain at high cardiovascular risk. Physicians are confronted with an array of antihypertensive agents, accompanied by increasingly complex and often conflicting evidence regarding their efficacy and tolerability.

SCOPE

An extensive PubMed and Cochrane database search was conducted to identify clinical literature (published 1990-2009) on the blood pressure lowering efficacy, tolerability and target organ protection of angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs). While not a systematic review, this article reviews the best available evidence in an attempt to clarify current uncertainty within medical practice regarding treatment options in patients with hypertension.

FINDINGS

ACEIs have been at the forefront of hypertension therapy for several years, especially in hypertensive at-risk patients. However, their use is restricted by burdensome side-effects and their limited ability to reach target blood pressure. Newer ARBs, such as telmisartan, have more sustained blood pressure control throughout the 24-h dosing period compared with ACEIs and other ARBs. For uncomplicated hypertension, ARBs are preferred to ACEIs because of their superior tolerability and adherence. In specific patient populations, namely heart failure patients, ARBs have previously shown equal cardiovascular protection to ACEIs. ONTARGET showed that an ARB, in this case telmisartan, was as effective as ramipril in reducing cardiovascular events in a wide cross-section of at-risk cardiovascular patients, but was better tolerated even though patients were screened for ACEI tolerance.

CONCLUSION

Telmisartan is currently the only ARB to have demonstrated equivalence to ramipril in reducing cardiovascular events in a broad patient population. In practical terms, telmisartan is superior to the reference standard ramipril because of more powerful blood pressure lowering and superior tolerability. However, in many countries, guidance to physicians prioritizes ACEIs. In these countries, telmisartan should be the first choice ARB for hypertensive at-risk patients who do not achieve adequate blood pressure control with an ACEI, or for whom tolerability is a concern.

Addressing the theoretical and clinical advantages of combination therapy with inhibitors of the renin-angiotensin-aldosterone system: antihypertensive effects and benefits beyond BP control

AIMS

This article reviews the importance of the renin-angiotensin-aldosterone system (RAAS) in the cardiometabolic continuum; presents the pros and cons of dual RAAS blockade with angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs); and examines the theoretical and practical benefits supporting the use of direct renin inhibitors (DRIs) in combination with ACEIs or ARBs.

MAIN METHODS

The author reviewed the literature for key publications related to the biochemical physiology of the RAAS and the pharmacodynamic effects of ACEIs, ARBs, and DRIs, with a particular focus on dual RAAS blockade with these drug classes.

KEY FINDINGS

Although ACEI/ARB combination therapy produces modest improvement in BP, it has not resulted in the major improvements predicted given the importance of the RAAS across the cardiorenal disease continuum. This may reflect the fact that RAAS blockade with ACEIs and/or ARBs leads to exacerbated renin release through loss of negative-feedback inhibition, as well as ACE/aldosterone escape through RAAS and non-RAAS-mediated mechanisms. Plasma renin activity (PRA) is an independent predictor of morbidity and mortality, even for patients receiving ACEIs and ARBs. When used alone or in combination with ACEIs and ARBs, the DRI aliskiren effectively reduces PRA. Reductions in BP are greater with these combinations, relative to the individual components alone.

SIGNIFICANCE

It is possible that aliskiren plus either an ACEI or ARB may provide greater RAAS blockade than monotherapy with ACEIs or ARBs, and lead to additive improvement in BP and clinically important outcomes.

The rationale and design of the antihypertensives and vascular, endothelial, and cognitive function (AVEC) trial in elderly hypertensives with early cognitive impairment: role of the renin angiotensin system inhibition

BACKGROUND

Prior evidence suggests that the renin angiotensin system and antihypertensives that inhibit this system play a role in cognitive, central vascular, and endothelial function. Our objective is to conduct a double-blind randomized controlled clinical trial, the antihypertensives and vascular, endothelial, and cognitive function (AVEC), to compare 1 year treatment of 3 antihypertensives (lisinopril, candesartan, or hydrochlorothiazide) in their effect on memory and executive function, cerebral blood flow, and central endothelial function of seniors with hypertension and early objective evidence of executive or memory impairments.

METHODS/DESIGN

The overall experimental design of the AVEC trial is a 3-arm double blind randomized controlled clinical trial. A total of 100 community eligible individuals (60 years or older) with hypertension and early cognitive impairment are being recruited from the greater Boston area and randomized to lisinopril, candesartan, or hydrochlorothiazide ("active control") for 12 months. The goal of the intervention is to achieve blood pressure control defined as SBP < 140 mm Hg and DBP < 90 mm Hg. Additional antihypertensives are added to achieve this goal if needed. Eligible participants are those with hypertension, defined as a blood pressure 140/90 mm Hg or greater, early cognitive impairment without dementia defined (10 or less out of 15 on the executive clock draw test or 1 standard deviation below the mean on the immediate memory subtest of the repeatable battery for the assessment of neuropsychological status and Mini-Mental-Status-exam >20 and without clinical diagnosis of dementia or Alzheimer's disease). Individuals who are currently receiving antihypertensives are eligible to participate if the participants and the primary care providers are willing to taper their antihypertensives. Participants undergo cognitive assessment, measurements of cerebral blood flow using Transcranial Doppler, and central endothelial function by measuring changes in cerebral blood flow in response to changes in end tidal carbon dioxide at baseline (off antihypertensives), 6, and 12 months. Our outcomes are change in cognitive function score (executive and memory), cerebral blood flow, and carbon dioxide cerebral vasoreactivity.

DISCUSSION

The AVEC trial is the first study to explore impact of antihypertensives in those who are showing early evidence of cognitive difficulties that did not reach the threshold of dementia. Success of this trial will offer new therapeutic application of antihypertensives that inhibit the renin angiotensin system and new insights in the role of this system in aging.

TRIAL REGISTRATION

Clinicaltrials.gov NCT00605072.

Clinical evidence from ONTARGET: the value of an angiotensin II receptor blocker and an angiotensin-converting enzyme inhibitor

The Heart Outcomes Prevention Evaluation study established the angiotensin-converting enzyme inhibitor ramipril, versus placebo, for prevention of cardiovascular events in high-risk patients. The ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET) was later conducted in similar high-risk patients using multifactorial treatment to control hypertension, platelet aggregation, and dyslipidemia, while comparing ramipril, telmisartan, or their combination, without placebo. In ONTARGET, the first angiotensin II receptor blocker-based study to be performed in a broader population of patients without congestive heart failure and/or left ventricular hypertrophy/dysfunction, telmisartan provided cardiovascular protection that was noninferior to ramipril. However, greater blockade of the renin-angiotensin system, using their combination, was not superior to ramipril alone. Telmisartan was better tolerated than ramipril in this high-risk population: notably, the incidence of cough and angioedema was significantly lower with telmisartan alone. Thus, telmisartan provides comparable efficacy to ramipril with less adverse events, which may encourage patient compliance.

Effect of smoking on cough reflex sensitivity in humans

Despite the importance of cigarette smoking as a cause of respiratory symptoms and disease, until recently there has been little attention on the effect of smoking on cough reflex sensitivity. Recent studies have shown that in otherwise healthy smokers, cough reflex sensitivity is diminished relative to that of nonsmokers. One proposed mechanism, chronic cigarette smoke-induced desensitization of airway cough receptors, is supported by the demonstration that smoking cessation leads to prompt enhancement of cough reflex sensitivity, even after many years of smoking. Furthermore, resumption of cigarette smoking promptly results in suppression of cough reflex sensitivity. These observations have introduced the concept that cough reflex sensitivity in humans is a dynamic phenomenon, able to be modulated by the presence or absence of stimuli such as cigarette smoke, even after prolonged exposure.

Interventional Case Series: Angiotensin-Converting Enzyme Inhibitor (ACE-I)–Induced Cough: Is Rechallenge With a Second ACE-I Worthwhile?

Angiotensin-converting enzyme inhibitors (ACE-Is) are a cornerstone of therapy with proven morbidity and mortality benefit in many disease states. The unpredictable, bothersome cough that occurs in 15% to 41% of patients oftentimes leads to noncompliance or discontinuation. Management of ACE-I-induced cough remains controversial. The authors’ objective was to determine whether patients experiencing an ACE-I-induced cough could be successfully switched to a different ACE-I without recurrent cough. A total of 10 participants deemed to have ACE-I-induced cough were enrolled in an interventional case series to assess whether they could tolerate rechallenge with an alternative ACE-I. During phase 1, ACE-I therapy was stopped for up to 4 weeks to allow the cough to resolve. During phase 2, participants were rechallenged with an alternative ACE-I and followed for 4 months. Of the 10 participants who consented to enroll, 6 were rechallenged with a second ACE-I. Cough recurred in 4 of these within 1 week (5-7 days), whereas 2 participants continued ACE-I therapy cough-free. Results suggest that a small percentage of patients with ACE-I-induced cough tolerate an alternative ACE-I. For patients with a true ACE-I-induced cough who are motivated to continue an ACE-I, a trial of a second ACE-I may be worthwhile.

Clinical Practice Guideline: Hoarseness (Dysphonia)

Objective:

This guideline provides evidence-based recommendations on managing hoarseness (dysphonia), defined as a disorder characterized by altered vocal quality, pitch, loudness, or vocal effort that impairs communication or reduces voice-related quality of life (QOL). Hoarseness affects nearly one-third of the population at some point in their lives. This guideline applies to all age groups evaluated in a setting where hoarseness would be identified or managed. It is intended for all clinicians who are likely to diagnose and manage patients with hoarseness.

Purpose:

The primary purpose of this guideline is to improve diagnostic accuracy for hoarseness (dysphonia), reduce inappropriate antibiotic use, reduce inappropriate steroid use, reduce inappropriate use of anti-reflux medications, reduce inappropriate use of radiographic imaging, and promote appropriate use of laryngoscopy, voice therapy, and surgery. In creating this guideline the American Academy of Otolaryngology—Head and Neck Surgery Foundation selected a panel representing the fields of neurology, speech-language pathology, professional voice teaching, family medicine, pulmonology, geriatric medicine, nursing, internal medicine, otolaryngology–head and neck surgery, pediatrics, and consumers.

Results

The panel made strong recommendations that 1) the clinician should not routinely prescribe antibiotics to treat hoarseness and 2) the clinician should advocate voice therapy for patients diagnosed with hoarseness that reduces voice-related QOL. The panel made recommendations that 1) the clinician should diagnose hoarseness (dysphonia) in a patient with altered voice quality, pitch, loudness, or vocal effort that impairs communication or reduces voice-related QOL; 2) the clinician should assess the patient with hoarseness by history and/or physical examination for factors that modify management, such as one or more of the following: recent surgical procedures involving the neck or affecting the recurrent laryngeal nerve, recent endotracheal intubation, radiation treatment to the neck, a history of tobacco abuse, and occupation as a singer or vocal performer; 3) the clinician should visualize the patient's larynx, or refer the patient to a clinician who can visualize the larynx, when hoarseness fails to resolve by a maximum of three months after onset, or irrespective of duration if a serious underlying cause is suspected; 4) the clinician should not obtain computed tomography or magnetic resonance imaging of the patient with a primary complaint of hoarseness prior to visualizing the larynx; 5) the clinician should not prescribe anti-reflux medications for patients with hoarseness without signs or symptoms of gastroesophageal reflux disease; 6) the clinician should not routinely prescribe oral corticosteroids to treat hoarseness; 7) the clinician should visualize the larynx before prescribing voice therapy and document/communicate the results to the speech-language pathologist; and 8) the clinician should prescribe, or refer the patient to a clinician who can prescribe, botulinum toxin injections for the treatment of hoarseness caused by adductor spasmodic dysphonia. The panel offered as options that 1) the clinician may perform laryngoscopy at any time in a patient with hoarseness, or may refer the patient to a clinician who can visualize the larynx; 2) the clinician may prescribe anti-reflux medication for patients with hoarseness and signs of chronic laryngitis; and 3) the clinician may educate/counsel patients with hoarseness about control/preventive measures.

Disclaimer:

This clinical practice guideline is not intended as a sole source of guidance in managing hoarseness (dysphonia). Rather, it is designed to assist clinicians by providing an evidence-based framework for decision-making strategies. The guideline is not intended to replace clinical judgment or establish a protocol for all individuals with this condition, and may not provide the only appropriate approach to diagnosing and managing this problem.

The role of RAS modification for primary and secondary stroke prevention

Clinical trial results indicate that the choice of antihypertensive agent can be a determinant of stroke protection, independent of blood pressure (BP) reduction. Angiotensin-converting enzyme inhibitors (ACE-Is) are effective for BP control and stroke protection, but their use may be limited by patient tolerability. Angiotensin receptor blockers appear to provide similar BP control compared with ACE-Is and may also offer the clinician the added benefit of primary and secondary stroke prevention, with the potential for fewer tolerability issues.

Complementary mechanisms of angiotensin receptor blockers and calcium channel blockers in managing hypertension

Hypertension affects approximately 73 million individuals in the United States. Clinical studies have shown that antihypertensive therapy can reduce blood pressure (BP) and the risk of cardiovascular events. However, the majority of patients with hypertension do not achieve the recommended BP goal of < 140/90 mm Hg (or < 130/80 mm Hg for patients with diabetes) with antihypertensive monotherapy, and require therapy with 2 or more antihypertensive agents. Combination therapy utilizes antihypertensive agents from different drug classes, which act via distinct pharmacologic mechanisms to improve overall efficacy and tolerability. Although combination therapy is superior to monotherapy in achieving BP goals across the entire spectrum of hypertension, the proportion of patients achieving the recommended BP goal can be further improved by the use of new antihypertensive drug combinations. The beneficial antihypertensive characteristics of both angiotensin receptor blockers and calcium channel blockers suggest that combining these classes may result in a highly efficacious antihypertensive therapy with regard to both activity and safety when used as a fixed-dose combination. In particular, a fixed-dose combination of olmesartan medoxomil plus amlodipine besylate has been demonstrated to be an efficacious antihypertensive combination due in part to the benefits associated with each of these agents within their respective drug classes.

Aliskiren: an oral direct renin inhibitor for the treatment of hypertension

Aliskiren is the first member of the new class of orally active direct renin inhibitors to receive approval from the United States Food and Drug Administration for the treatment of hypertension. In patients with hypertension, aliskiren can be used either as monotherapy or in combination with other antihypertensive agents. By inhibiting renin, aliskiren blocks the conversion of angiotensinogen to angiotensin I, which subsequently results in a reduction in angiotensin II concentrations. Unlike the angiotensin-converting enzyme inhibitors and the angiotensin II receptor blockers (ARBs), which reactively stimulate an increase in plasma renin activity, aliskiren suppresses the effects of renin and leads to a reduction in plasma renin activity. In clinical trials involving patients with mild-to-moderate hypertension, aliskiren provided antihypertensive efficacy that was comparable to that of an ARB. Combination therapy with aliskiren and an ARB may provide additional blood pressure-lowering effects compared with the respective monotherapies with each of the agents. The results from surrogate outcome studies have also alluded to the potential for aliskiren to prevent target organ damage. Because aliskiren does not significantly affect the cytochrome P450 system, it has been associated with few drug interactions. In clinical studies, aliskiren was well tolerated, and its adverse-effect profile was similar to that of placebo. Fatigue, headache, dizziness, diarrhea, nasopharyngitis, and back pain were the most commonly reported adverse events. Overall, aliskiren appears to be a reasonable treatment option for patients with mild-to-moderate hypertension who are intolerant of first-line antihypertensive therapies. Aliskiren may also be a promising renoprotective strategy in patients with concomitant hypertension and diabetes mellitus. Its potential as a first-line antihypertensive agent will have to be further examined once studies evaluating its effects on long-term clinical outcomes are completed.

Peripheral mechanisms II: the pharmacology of peripherally active antitussive drugs

Cough is an indispensable defensive reflex. Although generally beneficial, it is also a common symptom of diseases such as asthma, chronic obstructive pulmonary disease, upper respiratory tract infections, idiopathic pulmonary fibrosis and lung cancer. Cough remains a major unmet medical need and although the centrally acting opioids have remained the antitussive of choice for decades, they have many unwanted side effects. However, new research into the behaviour of airway sensory nerves has provided greater insight into the mechanisms of cough and new avenues for the discovery of novel non-opioid antitussive drugs. In this review, the pathophysiological mechanisms of cough and the development of novel antitussive drugs are reviewed.

Using guinea pigs in studies relevant to asthma and COPD

The guinea pig has been the most commonly used small animal species in preclinical studies related to asthma and COPD. The primary advantages of the guinea pig are the similar potencies and efficacies of agonists and antagonists in human and guinea pig airways and the many similarities in physiological processes, especially airway autonomic control and the response to allergen. The primary disadvantages to using guinea pigs are the lack of transgenic methods, limited numbers of guinea pig strains for comparative studies and a prominent axon reflex that is unlikely to be present in human airways. These attributes and various models developed in guinea pigs are discussed.

Adverse drug reactions in patients with cardiovascular disease

Adverse drug reactions (ADRs) occur frequently in modern medical practice, increasing morbidity and mortality and inflating the cost of care. Patients with cardiovascular disease are particularly vulnerable to ADRs due to their advanced age, polypharmacy, and the influence of heart disease on drug metabolism. The ADR potential for a particular cardiovascular drug varies with the individual, the disease being treated, and the extent of exposure to other drugs. Knowledge of this complex interplay between patient, drug, and disease is a critical component of safe and effective cardiovascular disease management. The majority of significant ADRs involving cardiovascular drugs are predictable and therefore preventable. Better patient education, avoidance of polypharmacy, and clear communication between physicians, pharmacists, and patients, particularly during the transition between the inpatient to outpatient settings, can substantially reduce ADR risk.

Optimal drug treatment of systolic hypertension in the elderly

Approximately two-thirds of the elderly population has hypertension, mainly of the isolated systolic hypertension (ISH) type. However, while large-scale, randomized controlled intervention trials have demonstrated that treatment of ISH reduces rates of total mortality, cardiovascular mortality and stroke in older hypertensives, control of ISH in the elderly remains poor. The aim of this review of drug treatment of ISH in the elderly is to provide a succinct, practical and clinically orientated guide that summarizes international recommendations and practices with special emphasis on newer approaches. Knowledge of pathophysiological changes in older subjects (decreased elastic artery compliance, reduced plasma renin activity, increased salt sensitivity) and evidence from epidemiological surveys and randomized controlled trials give clear clues that thiazide(-like) diuretics and long-acting dihydropyridine calcium channel antagonists are the drugs of choice in the treatment of ISH. Thus, based on this evidence, American, European and international guidelines for hypertension management still offer the best available recommendations for optimal treatment of ISH in the elderly. Newer combination treatments, especially the fixed combination of a dihydropyridine calcium channel antagonist and an ACE inhibitor, have valuable benefits in terms of efficacy and tolerability. Use of nitrates added to other antihypertensive medications can provide the practising physician with a further unconventional therapeutic strategy.

Efficacy and safety of olmesartan medoxomil and hydrochlorothiazide compared with benazepril and amlodipine besylate

BACKGROUND

Most patients with stage 2 hypertension require two or more antihypertensive agents in order to achieve the BP goals recommended in current treatment guidelines. Accordingly, combinations of two drugs with different mechanisms of antihypertensive action are widely used.

OBJECTIVE

The aim of this randomized, double-blind, multicenter 12-week study was to compare the efficacy, safety, and tolerability of a combination of olmesartan medoxomil/hydrochlorothiazide (HCTZ) with that of benazepril plus amlodipine besylate in patients with stage 2 hypertension.

METHODS

Patients were eligible for randomization following a 3- to 4-week placebo run-in period if they had either (i) mean seated DBP>or=90 mm Hg but<115 mm Hg and mean seated SBP>or=160 mm Hg but <200 mm Hg, or (ii) mean seated DBP>or=100 mm Hg but<115 mm Hg. The difference in mean seated SBP measured on two separate visits during the run-in period was required to be<or=15 mm Hg. In addition, a mean 8-hour daytime ambulatory DBP>or=95 mm Hg and<115 mm Hg or SBP>145 mm Hg and<or=190 mm Hg were required. Eligible patients were randomized 1:1 to treatment with olmesartan medoxomil (20 mg/day for 2 weeks; then 40 mg/day for 2 weeks; then olmesartan medoxomil/HCTZ 40/12.5 mg/day for 4 weeks; then olmesartan medoxomil/HCTZ 40/25 mg/day for 4 weeks) or benazepril (10 mg/day for 2 weeks; then 20 mg/day for 2 weeks; then benazepril 20 mg/day plus amlodipine besylate 5 mg/day for 4 weeks; then benazepril 20 mg/day plus amlodipine besylate 10 mg/day for 4 weeks). The primary endpoint was change from baseline in mean SBP at the end of week 12 (end of study). Secondary endpoints included DBP after completion of monotherapy and combination therapy at the end of weeks 4 and 12, SBP at the end of week 4, and percentage of patients attaining BP goals of<140/90 mm Hg, <130/85 mm Hg, and<130/80 mm Hg at the end of weeks 4 and 12.

RESULTS

One-hundred and ninety patients were randomized and received at least one dose of study medication. The primary efficacy endpoint of change in mean seated SBP at week 12 was significantly greater with olmesartan medoxomil/HCTZ than with benazepril plus amlodipine besylate (least square [LS] mean change: -32.5 vs -26.5 mm Hg, p=0.024; LS mean treatment difference -6.0 mm Hg; 95% CI -11.1, -0.8 mm Hg). The LS mean change for reduction in DBP approached statistical significance with olmesartan medoxomil/HCTZ compared with the benazepril-based regimen (p=0.056) at week 12 (end of study). BP reductions showed statistically significant differences between treatment groups favoring olmesartan medoxomil/HCTZ in both SBP and DBP at week 8. The percentage of patients achieving goal rates at the end of the study for olmesartan medoxomil/HCTZ and benazepril plus amlodipine besylate, respectively, were 66.3% versus 44.7% (p=0.006) for<140/90 mm Hg, 44.9% versus 21.2% (p=0.001) for<130/85 mm Hg, and 32.6% versus 14.1% (p=0.006) for<130/80 mm Hg. Both treatments were well tolerated.

CONCLUSIONS

Olmesartan medoxomil/HCTZ 40/12.5 and 40/25 mg/day combination therapy was well tolerated and demonstrated a greater antihypertensive effect than benazepril plus amlodipine besylate 20/5 and 20/10 mg/day and this enabled more patients to achieve targeted BP goals.

A composite screening tool for medication reviews of outpatients: general issues with specific examples

Regular performance of medication reviews is prominent among methods that have been advocated to reduce the extent and seriousness of drug-related problems, such as adverse drug reactions, drug-disease interactions, drug-drug interactions, drug ineffectiveness and cost ineffectiveness. Several screening tools have been developed to guide practising healthcare professionals and researchers in reviewing the medication patterns of elderly patients; however, each of these tools has its own limitations. This review discusses a wide range of general prescription-, treatment- and patient-related issues that should be taken into account when reviewing medication patterns by implicit screening. These include generic and therapeutic substitution; potentially superfluous or inappropriate medications; potentially inappropriate dosages or duration of treatment; drug-disease and drug-drug interactions; under-treatment; making use of laboratory test results; patient adherence, experiences and habits; appropriate dosage forms and packaging. A broad selection of specific examples and references that can be used as a basis for explicit screening of medication patterns in outpatients is also offered.

Chronic cough: the allergist's perspective

Cough is a common presenting symptom of many patients managed by allergists. For patients with chronic cough who are nonsmokers, have normal spirometry, and are not being treated with an ACE inhibitor, diagnosis usually focuses on differentiation between postnasal drip syndrome, asthma, gastroesophageal reflux disease, and nonasthmatic eosinophilic bronchitis, alone or in combination. Patients with severe COPD or GERD should be referred to appropriate specialists for those conditions. The management of conditions commonly treated by allergists (e.g., allergic rhinitis, asthma, sinusitis) follows the recommendations of current guidelines and/or practice parameters.

Rational design of 6-(2,4-diaminopyrimidinyl)-1,4-benzoxazin-3-ones as small molecule renin inhibitors

We report the design and synthesis of a series of 6-(2,4-diaminopyrimidinyl)-1,4-benzoxazin-3-ones as orally bioavailable small molecule inhibitors of renin. Compounds with a 2-methyl-2-aryl substitution pattern exhibit potent renin inhibition and good permeability, solubility, and metabolic stability. Oral bioavailability was found to be dependent on metabolic clearance and cellular permeability, and was optimized through modulation of the sidechain that binds in the S3(sp) subsite.

Nonallergic angioedema: role of bradykinin

Angioedema is an underestimated clinical problem. Many cases are nonallergic reactions, e.g. bradykinin-induced angioedema caused by genetic defects and angiotensin-converting enzyme (ACE) inhibitors. This difference is crucial for successful therapy, in particular when complete emergency care is not available. Five important forms of nonallergic angioedema can be distinguished: hereditary (HAE), acquired (AAE), renin-angiotensin-aldosterone system (RAAS)-blocker-induced (RAE), pseudoallergic angioedema (PAE) and idiopathic angioedema (IAE). Some angioedema are present in the larynx and may cause death. A vast majority of nonallergic angioedema are RAE, particularly those caused by ACE inhibitors. It appears important to emphasize that in patients with complete intolerance to RAAS-blockers, cessation of RAAS-blockers is likely to be associated with increased cardiovascular risk. Currently, there is no published algorithm for diagnosis and treatment. Angioedema is usually treated by a conservative clinical approach using artificial ventilation, glucocorticoids and antihistamines. Today, a plasma pool C1-esterase inhibitor (C1-INH) concentrate is the therapy of choice in HAE. The current pharmacotherapy of nonallergic angioedema is not satisfactory, thus requiring the identification of effective agents in clinical trials. Recently, several new drugs were developed: a recombinant C1-INH, a kallikrein inhibitor (ecallantide) and a specific bradykinin-B2-receptor antagonist (icatibant). According to currently available reports, these drugs may improve the treatment of kinin-induced angioedema.

A comparison of the tolerability of the direct renin inhibitor aliskiren and lisinopril in patients with severe hypertension

Patients with severe hypertension (>180/110 mm Hg) require large blood pressure (BP) reductions to reach recommended treatment goals (<140/90 mm Hg) and usually require combination therapy to do so. This 8-week, multicenter, randomized, double-blind, parallel-group study compared the tolerability and antihypertensive efficacy of the novel direct renin inhibitor aliskiren with the angiotensin converting enzyme inhibitor lisinopril in patients with severe hypertension (mean sitting diastolic blood pressure (msDBP)>or=105 mm Hg and <120 mm Hg). In all, 183 patients were randomized (2:1) to aliskiren 150 mg (n=125) or lisinopril 20 mg (n=58) with dose titration (to aliskiren 300 mg or lisinopril 40 mg) and subsequent addition of hydrochlorothiazide (HCTZ) if additional BP control was required. Aliskiren-based treatment (ALI) was similar to lisinopril-based treatment (LIS) with respect to the proportion of patients reporting an adverse event (AE; ALI 32.8%; LIS 29.3%) or discontinuing treatment due to AEs (ALI 3.2%; LIS 3.4%). The most frequently reported AEs in both groups were headache, nasopharyngitis and dizziness. At end point, ALI showed similar mean reductions from baseline to LIS in msDBP (ALI -18.5 mm Hg vs LIS -20.1 mm Hg; mean treatment difference 1.7 mm Hg (95% confidence interval (CI) -1.0, 4.4)) and mean sitting systolic blood pressure (ALI -20.0 mm Hg vs LIS -22.3 mm Hg; mean treatment difference 2.8 mm Hg (95% CI -1.7, 7.4)). Responder rates (msDBP<90 mm Hg and/or reduction from baseline>or=10 mm Hg) were 81.5% with ALI and 87.9% with LIS. Approximately half of patients required the addition of HCTZ to achieve BP control (ALI 53.6%; LIS 44.8%). In conclusion, ALI alone, or in combination with HCTZ, exhibits similar tolerability and antihypertensive efficacy to LIS alone, or in combination with HCTZ, in patients with severe hypertension.

Angiotensin‐Converting Enzyme Inhibition—Emerging Pulmonary Issues Relating to Cough

Angiotensin-converting enzyme (ACE) inhibitors are viewed by many as important treatment options for both the management of hypertension and the provision of end-organ protection. ACE inhibitors have not been looked on as having any clearly recognizable direct pulmonary benefits; rather, their pulmonary effects have been felt to be a nuisance by virtue of their association with cough. ACE inhibitor-related cough is well characterized. What is less well appreciated is the relationship between sleep apnea, pneumonia, and ACE inhibitor-related cough. These new pulmonary observations in patients afflicted with an ACE inhibitor-related cough should revive interest in this bothersome side effect.

Binding thermodynamics of substituted diaminopyrimidine renin inhibitors

Renin is an aspartyl protease involved in the production of angiotensin II, a potent vasoconstrictor. Renin inhibitors can prevent blood vessel constriction and therefore could be useful for the treatment of hypertension. High-throughput screening efforts identified a small molecule renin inhibitor with a core substituted diaminopyrimidine ring. Parallel medicinal chemistry efforts based on this lead resulted in compound 1. A complex of 1 bound to renin was crystallized, and structural data were obtained by X-ray diffraction. The structure indicated that there were adjacent unoccupied binding pockets. Synthetic efforts were initiated to extend functionality into these pockets so as to improve affinity and adjust pharmacokinetic parameters. Thermodynamics data for inhibitor binding to renin were also collected using isothermal titration calorimetry. These data were used to help guide inhibitor optimization by suggesting molecular alterations to improve binding affinity from both thermodynamic and structural perspectives. The addition of a methoxypropyl group extending into the S3 subpocket improved inhibitor affinity and resulted in greater binding enthalpy. Initial additions to the pyrimidine ring template that extended into the large hydrophobic S2 pocket did not improve affinity and dramatically altered the thermodynamic driving force for the binding interaction. Binding of the core template was enthalpically driven, whereas binding of initial inhibitors with S2 extensions was both enthalpically and entropically driven but lost significant binding enthalpy. Additional electrostatic interactions were then incorporated into the S2 extension to improve binding enthalpy while taking advantage of the favorable entropy.

Encoding of the cough reflex

Coughing can be both voluntarily induced and involuntarily initiated by activation of vagal afferent nerves innervating the airways and lungs. Centrally, cough is regulated at the level of the brainstem through integration of vagal afferent nerve input by relay neurones in the nucleus tractus solitarius (nTS). Projections to and from the nTS add further complexity to cough regulation, as do the profound influences of psychological and social factors known to regulate cough. Peripherally, both neuronal and non-neuronal elements in the airways regulate the excitability of the vagal afferent nerve terminals regulating cough. These multiple levels of integration and encoding of the cough reflex may render this defensive respiratory response highly susceptible to modulation both by disease processes and through therapeutic intervention.

Interpreting the histopathology of chronic cough: a prospective, controlled, comparative study

HYPOTHESIS

Trauma from chronic coughing produces airway inflammation similar to diseases causing cough.

DESIGN

Prospective, cross-sectional, controlled, clinicopathologic correlation study in four groups: group 1, cough from intrapulmonary diseases; group 2, cough from extrapulmonary diseases; group 3, cough that was unexplained; and group 4, nonsmoking, asymptomatic control subjects.

METHODS

Patients with chronic cough underwent a standardized workup including endobronchial biopsies before treatment. Causes were determined by a favorable response to therapy. Bronchial biopsy samples from control subjects were obtained from surgical specimens.

RESULTS

There were 24 adult subjects (13 women and 11 men) with mean cough duration of 8.6 +/- 7.4 years (+/- SD). Thirteen patients had cough due to a specific disease: intrapulmonary diseases in 5 patients, and extrapulmonary diseases in 8 patients. Eleven patients had unexplained cough. Compared to control subjects, there was minimal-to-moderate chronic inflammation in all coughers (p < or = 0.0004), in group 1 (p < or = 0.039), group 2 (p = 0.061), and group 3 (p < or = 0.025) diseases that were not correlated with cough duration. There was no difference in type of inflammation, cough duration, or smoking history between groups, nor were there histologic differences between subjects with explained causes of cough compared with unexplained cough.

CONCLUSIONS

Our findings suggest that airway inflammation associated with chronic cough, assessed on morphologic appearance and inflammatory cell counting in hematoxylin-eosin-prepared samples, may be due to the trauma of coughing, and the inflammation may be similar to that seen with diseases putatively thought to cause chronic cough. Investigators must be cautious when attributing pathogenic importance to observed inflammatory changes in airways of coughing subjects.

Efficacy of Angiotensin Receptor Blockers in Cardiovascular Disease

The cardiovascular continuum describes the progression of pathophysiologic events from cardiovascular risk factors to symptomatic cardiovascular disease (CVD) and life-threatening events. Pharmacologic intervention early in the continuum may prevent or slow CVD development and improve quality of life. The renin-angiotensin-aldosterone system (RAAS) is central to the pathophysiology of CVD at many stages of the continuum. Numerous clinical trials of angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) have shown that RAAS blockade provides benefits to patients across the continuum. ARBs are as effective as ACE inhibitors in the treatment of hypertension; however tolerability and adherence to therapy appear to be improved with ARBs. Large clinical trials have shown that ARBs may provide therapeutic benefits beyond blood pressure control in patients with diabetes, heart failure or at risk of heart failure following a myocardial infarction. In addition, ARBs have been shown to provide protective effects in patients with impaired renal function or left ventricular hypertrophy. Additional clinical trials are ongoing to further characterize the role of ARBs in CVD management.

Potential side effects of renin inhibitors – mechanisms based on comparison with other renin–angiotensin blockers

Angiotensin (Ang) II plays important roles in the development of hypertension and cardiovascular and renal injury. Pharmaceutical approaches to block its activity led to the development of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. Numerous trials have documented their efficacy in controlling blood pressure, minimising left ventricular remodelling, preventing progression to heart failure, ameliorating proteinuria and retarding renal disease progression. Although they are considered safe in general, there remain concerns about the potential for adverse events in certain target populations. Recently, several novel, low molecular weight renin inhibitors without the extended peptide-like backbone of previous renin inhibitors were developed with favourable pharmacokinetic properties. They have been shown to successfully reduce Ang II levels in normal volunteers and to lower blood pressure in patients with mild-to-moderate hypertension. In this review, the authors summarise current knowledge about these renin inhibitors.