ACE-inhibitor-induced cough, an adverse drug reaction unrecognised for several years: studies in prescription-event monitoring

A design for prescription-event monitoring in Japan (J-PEM)

OBJECTIVES

To present a design for Prescription-Event Monitoring in Japan (J-PEM).

METHODS

In J-PEM, pharmacists are asked to register patients who are prescribed the 'test drug' or a 'control drug' for the first time ever, the drug, and prescribing physician. Although J-PEM does not identify all users of a drug, this method provides concurrent controls. In J-PEM, a questionnaire for the pharmacist and one for the prescribing physician are mailed 6 months after the drug to be monitored is first prescribed to a patient. Doctors and pharmacists are asked to report events that occurred in the patient after the drug was prescribed. The questionnaire for the physician includes questions that are specific to the class of drug that was prescribed, to obtain information on possible confounding variables. Pharmacists are requested to give information on all concomitant drugs used by the patient during or for a part of the period that the patient was taking the drug to be monitored.

RESULTS AND CONCLUSIONS

Compared with the UK PEM, the weakness of J-PEM is its inability to identify all users of a drug, and its strengths are the availability of concurrent controls and a relatively large amount of information per patient.

Detection, verification, and quantification of adverse drug reactions

The current system of verifying and quantifying adverse reactions to new drugs is too disparate. Epidemiological studies for testing a hypothesis have a part to play in protecting the public from the harmful effects of new drugs

Treatment of systemic hypertension in patients with pulmonary disease: COPD and asthma

We present a two-part review of the English-language literature pertaining to drug therapy for systemic high BP in patients with pulmonary diseases. Part I examines the literature pertaining to the use of antihypertensive drugs in patients with systemic hypertension and coexisting pulmonary conditions, especially COPD and asthma. Part II of the series reviews studies assessing the relationship between sleep-disordered breathing (including the role of the sympathetic nervous system) and systemic hypertension, and presents an approach to the management of these patients. It is the aim of both parts of this review to make qualified conclusions and recommendations applying a methodologic critique to assess the current literature. In the first part of this series, we review the demographics of hypertension in patients with COPD. This is followed by an extensive review of the use of specific classes of antihypertensive drug therapies in patients with pulmonary disease. The antihypertensive agents reviewed include diuretics, calcium antagonists, angiotensin-converting enzyme inhibitors, and angiotensin II receptor antagonists, beta-adrenergic blocking agents, and alpha-beta-blockers and other non-beta-blocker classes. Additionally, the renin angiotensin system is briefly reviewed, with a discussion of how angiotensin-converting enzyme inhibitors induce cough, especially in pulmonary and congestive heart failure patients.

Causal association in pharmacovigilance and pharmacoepidemiology: thoughts on the application of the Austin Bradford-Hill criteria

The methods used for the evaluation of drug safety signals (including major signals leading to withdrawal of products from the market) are inconsistent and sometimes of poor quality. While the assessment of the safety of medicines needs to consider specific issues such as drug interactions and variation in compliance, the general principles, which are used to study environmental hazards, can be applied for this purpose. The criteria proposed by Sir Austin Bradford-Hill more than 35 years ago for attributing disease causation to environmental factors have been used widely in epidemiology, are applicable to pharmacovigilance and pharmacoepidemiology. The Austin Bradford-Hill criteria include strength, consistency, specificity, temporality, biological gradient, plausibility, coherence, experimental evidence and analogy. The paper reviews each of these criteria with emphasis on pharmacovigilance and pharmacoepidemiology and with some examples. The application of the Austin Bradford-Hill criteria to the evaluation of causal association in pharmacovigilance and pharmacoepidemiology is very useful. However, it requires understanding of the limitations of the data, such as, under-reporting, poor quality of information from third parties and misclassification. Further work is required to develop strategies to handle these limitations.

ACE inhibitor-induced bronchial reactivity in patients with respiratory dysfunction

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibitors are often associated with an increased incidence of cough and bronchial responsiveness that may cause further deterioration of patients with impaired pulmonary function.

OBJECTIVE

To review the available literature on the incidence of cough and bronchial responsiveness associated with ACE-inhibitor therapy in patients with asthma, chronic obstructive pulmonary disease (COPD), and congestive heart failure (CHF).

DATA SOURCES

Literature was accessed through MEDLINE (1985-September 2001). Key search terms included cough, bronchospasm, asthma, congestive heart failure, chronic obstructive pulmonary disease, ACE inhibitors, and angiotensin II receptor blockers.

DATA SYNTHESIS

The literature reports several cases of increased bronchial responsiveness associated with ACE inhibitors. Larger, controlled studies evaluating the increased risk in patients with pulmonary dysfunction are limited. Data from these trials are summarized in this article.

CONCLUSIONS

The literature shows that patients with primary airway disease such as asthma and COPD are not at an increased risk of developing cough or bronchoconstriction as a result of ACE-inhibitor therapy. Despite the ability of ACE inhibitors to improve exercise tolerance, perfusion, and gas transfer, patients with CHF may be at higher risk of developing cough than the general population. Whether this cough is attributed to ACE inhibition or increased left-ventricular dysfunction remains uncertain. If increased bronchial responsiveness does occur, angiotensin II receptor antagonists are another reasonable option.

Spontaneous cervical epidural hematoma associated with oral anticoagulant therapy

A 54-year-old woman who was on anticoagulant treatment with acenocoumarol for a mitral prothesis developed a cervical spinal epidural hematoma, probably triggered by coughing fits together with supratherapeutic anticoagulation. Because of the subacute evolution of the hematoma, it was not diagnosed until the patient was admitted to the hospital with profuse hemorrhages. Given the subacute nature of the hematoma, along with the favorable evolution, conservative treatment with dexamethasone was decided upon, and it was resolved with almost no sequelae. This unusual clinical entity definitely should be suspected in patients on anticoagulants who complain of severe localized neck pain, most often with radicular irradiation.

Pharmacovigilance: a science or fielding emergencies?

Pharmacovigilance involves the assessment of risks and benefits of medicines. There are legal and regulatory aspects of this process, and the licensing of a new medicine is always provisional. The systems, in the past, have had limited statistical involvement, either in terms of personnel who are statistically trained, or in terms of statistical methods. This is changing. The high profile activities of pharmacovigilance have often been emergencies, though most is routine activity. Application of statistical thinking and of techniques is being done to help detect adverse effects of medicines rather earlier so that some emergencies may be avoided.

Recent insight into therapy of congestive heart failure: focus on ACE inhibition and angiotensin-II antagonism

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.

ACE inhibitor- versus angiotensin II blocker-induced cough and angioedema

OBJECTIVE

To compare the tolerability of angiotensin-converting enzyme (ACE) inhibitors with that of angiotensin II (AII)-receptor blockers and the incidence of cough and angioedema associated with their use through review of published data.

DATA SOURCES

References were identified through a MEDLINE search of articles published between January 1975 and April 1997. Bibliographies of pertinent references were also reviewed.

RESULTS

Results of placebo-controlled and comparative trials of the AII blockers demonstrate that they are at least as effective as ACE inhibitors for hypertension, but exhibit an incidence of cough and absent or rare angioedema like that of placebo.

CONCLUSIONS

In the 10 comparative trials described, all reported a lower incidence of cough with AII blockers than with ACE inhibitors. Angioedema was not reported in the comparative trials described.