Rise and fall of asthma-related mortality in Italy and sales of beta2-agonists, 1980-1994

Post-Marketing Regulation of Medicines Withdrawn from the Market Because of Drug-Attributed Deaths: An Analysis of Justification

INTRODUCTION

Several medicinal products have been withdrawn from the market because of drug-attributed deaths. However, there has been no investigation of whether such withdrawals were justified, and the extent to which confirmatory studies are used to investigate drug-adverse event relationships when deaths are reported is uncertain. We documented medicinal products withdrawn from the market because of drug-attributed deaths, identified confirmatory studies investigating the drug-adverse event relationships, examined whether withdrawals of medicinal products because of drug-attributed deaths after marketing were justified based on a mechanistic analysis, and examined the trends over time.

METHODS

We searched electronic and non-electronic sources to identify medicinal products that were withdrawn because of drug-attributed deaths. We used a previously published algorithm to examine whether the withdrawals of products were justified. We then searched PubMed and Google Scholar to identify studies investigating the drug-adverse event relationships, used the Oxford Centre for Evidence-Based Medicine criteria to document the levels of evidence, and assessed whether the evidence of an association was confirmed.

RESULTS

We included 83 medicinal products. The reasons for withdrawal appeared to have been justified in 80 cases (96%). The median interval between the first reported adverse reaction that was related to the cause of death and the first reported death was 1 year (interquartile range = 1-3); products were withdrawn sooner when the interval between the first reported relevant adverse reaction and the first death was shorter. Confirmatory studies were conducted in 57 instances (69%), and there was evidence of an association in 52 cases (63%). Four products (5%) were re-introduced after initial withdrawal.

CONCLUSION

Regulatory authorities have been justified in making withdrawal decisions when deaths have been attributed to medicinal products, using the precautionary principle when alternative decisions could have been made. Medicinal products are likely to be quickly withdrawn from the market when there is a short interval to the first reported deaths. The use of an algorithm such as we have used in this study could help to expedite the process of decision making.

Asthma mortality and long-acting beta2-agonists in five major European countries, 1994-2004

OBJECTIVES

Over the last few decades, important changes occurred in the pharmacological approach to asthma control. However, the possible link between pharmacologic treatment and asthma death remains controversial.

STUDY DESIGN AND SETTING

Age-standardized asthma mortality rates were computed over the 1994-2004 period for France, Germany, Spain, the UK, and Italy. Rates for children and young adults 5 to 34 years of age, middle age adults 35 to 64 years of age, and elderly adults > or = 65 years. Joinpoint regression was performed to identify years where significant changes in mortality trends occurred. Consumption of inhaled long-acting beta-2-agonists (LABA), including inhaled corticosteroids (ICS) when combined with LABAs in a single inhaler, derived from sales estimates.

RESULTS

In 1994, the highest asthma mortality rates were in Germany (4.7/100,000), and the lowest ones were in Italy and Spain (0.5/100,000). Steady downward trends were observed in all the countries considered. The largest decline was registered in Germany and the smallest one was in the UK. LABA sales increased steadily since 1994, particularly in France, Spain, and the UK, reaching values around 14 Defined Daily Doses (DDD)/1,000 inhabitants in 2004.

CONCLUSION

While the use of LABAs (with or without ICS) increased over the last decade, asthma mortality declined in major western European countries.

Adverse effects of beta-agonists: are they clinically relevant?

Inhaled beta(2)-adrenoceptor agonists (beta(2)-agonists) are the most commonly used asthma medications in many Western countries. Minor adverse effects such as palpitations, tremor, headache and metabolic effects are predictable and dose related. Time series studies suggested an association between the relatively nonselective beta-agonist fenoterol and asthma deaths. Three case-control studies confirmed that among patients prescribed fenoterol, the risk of death was significantly elevated even after controlling for the severity of asthma. The Saskatchewan study not only found an increased risk of death among patients dispensed fenoterol, but also suggested this might be a class effect of beta(2)-agonists. However, in subsequent studies, the long-acting beta(2)-agonist salmeterol was not associated with increased asthma mortality. In a case-control study blood albuterol (salbutamol) concentrations were found to be 2.5 times higher among patients who died of asthma compared with controls. It is speculated that such toxic concentrations could cause tachyarrhythmias under conditions of hypoxia and hypokalemia. The risk of asthma exacerbations and near-fatal attacks may also be increased among patients dispensed fenoterol, but this association may be largely due to confounding by severity. Although salmeterol does not appear to increase the risk of near-fatal attacks, there is a consistent association with the use of nebulized beta(2)-agonists. Nebulized and oral beta(2)-agonists are also associated with an increased risk of cardiovascular death, ischemic heart disease and cardiac failure. Caution should be exercised when first prescribing a beta-agonist for patients with cardiovascular disease. A potential mechanism for adverse effects with regular use of beta(2)-agonists is tachyphylaxis. Tachyphylaxis to the bronchodilator effects of long-acting beta(2)-agonists can occur, but has been consistently demonstrated only for formoterol (eformoterol) a full agonist, rather than salmeterol, a partial agonist. Tachyphylaxis to protection against induced bronchospasm occurs with both full and partial beta(2)-agonists, and probably within a matter of days at most. Underlying airway responsiveness to directly acting bronchoconstricting agents is not increased when the bronchodilator effect of the regular beta(2)-agonist has been allowed to wear off, although there may be an increase in responsiveness to indirectly acting agents. While there has been speculation that underlying airway inflammation in asthma may be made worse by regular use of short-acting beta(2)-agonists, in contradistinction, a number of studies have shown that long-acting beta(2)-agonists have positive anti-inflammatory effects. An Australian Cochrane Airways Group systematic review of the randomized, controlled trials of short-acting beta-agonists found only minimal and clinically unimportant differences between regular use and use as needed. Regular short-acting treatment was better than placebo. However, a subsequent systematic review has found that regular use of long-acting beta-agonists had significant advantages over regular use of short-acting beta-agonists. More studies and data are needed on the regular use of beta(2)-agonists in patients not taking inhaled corticosteroids, and in potentially vulnerable groups, such as the elderly and those with particular genotypes for the beta-receptor, who might be more prone to adverse effects.