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Effectiveness of Anti-arrhythmic Drugs: Amiodarone and Lidocaine, for treating sudden cardiac arrest, increasing likelihood of Patients Surviving Emergency Transport to Hospital

Curator: Aviva Lev-Ari, PhD, RN

 

Original Study

http://www.nejm.org/doi/full/10.1056/NEJMoa1514204

Editorial

Out-of-Hospital Cardiac Arrest — Are Drugs Ever the Answer? Jose A. Joglar, M.D., and Richard L. Page, M.D.

http://www.nejm.org/doi/pdf/10.1056/NEJMe1602790

Monday, April 4, 2016

Antiarrhythmic drugs found beneficial when used by EMS treating cardiac arrest

Researchers have confirmed that certain heart rhythm medications, when given by paramedics to patients with out-of-hospital cardiac arrest who had failed electrical shock treatment, improved likelihood of patients surviving transport to the hospital. The study was published online in the New England Journal of Medicine and helps answer a longstanding scientific question about the effectiveness of two widely-used antiarrhythmic drugs, amiodarone and lidocaine, for treating sudden cardiac arrest.

“This trial shows that amiodarone and lidocaine offer hope for bringing patients back to life and into the hospital after cardiac arrest.”

Peter Kudenchuk, M.D., Principal Study Author

The study followed the patients from hospital admission to hospital discharge. Although neither drug significantly improved the overall rate of survival to hospital discharge, amiodarone showed a favorable trend in that direction. Survival to discharge is the point at which a patient is discharged from the hospital.

“This trial shows that amiodarone and lidocaine offer hope for bringing patients back to life and into the hospital after cardiac arrest,” said principal study author Peter Kudenchuk, M.D., a cardiac electrophysiologist at the University of Washington Medical Center in Seattle. “While the overall increase in survival to hospital discharge of about 3 percent with amiodarone was not statistically significant, it came very close. Importantly, there was a significant improvement in survival to hospital discharge with either drug when the cardiac arrest was bystander-witnessed.” A bystander-witnessed cardiac arrest is one that is witnessed by another person.

Sudden cardiac arrest is a condition in which the heart suddenly or unexpectedly stops beating, cutting off blood flow to the brain and other vital organs. More than 300,000 people are treated for out-of-hospital cardiac arrest each year, with the vast majority occurring at home, according to the American Heart Association. Studies show that nationally only about 10 percent of people who suffer cardiac arrest outside the hospital survive. Effective treatments, such as CPR and defibrillation, can greatly increase a victim’s chance of survival. This study adds the possibility of additional benefit from the use of the heart rhythm medications.

EMS (emergency medical services) providers commonly use antiarrhythmic drugs for out-of-hospital cardiac arrest that is not responsive to defibrillation shocks to the heart for restoring its normal rhythm. However, doctors remain unclear whether these drugs have proven survival benefit or if any benefit might be undone by possible drug side effects. As a result, use of these treatments by paramedics varies.

The three-year study began in 2012, and randomized 3,026 patients with out-of-hospital cardiac arrest caused by ventricular fibrillation and ventricular tachycardia, life-threatening rhythms of the heart’s lower pumping chambers that are often resistant to electrical shock.

Researchers assigned the patients to treatment with amiodarone, lidocaine, or neither drug (a saline placebo) by rapid injection, along with all other standard resuscitation treatments. The study was conducted by the Resuscitation Outcomes Consortium (link is external), which includes clinical sites in the United States and Canada.

“Survival among the approximately 1,900 patients in the study whose cardiac arrest was witnessed by a bystander was improved significantly, from about 23 percent to 28 percent, by either drug,” Dr. Kudenchuk said.  Better than half of study participants fit this bystander-witnessed category, a group that was identified before the study began as potentially more likely to respond to such treatment. “This suggests treating patients as soon as possible after their collapse might be a critical determinant of whether drugs like amiodarone or lidocaine will have a significant clinical effect,” he added.

“I’m encouraged by the fact that though seemingly small, the 3-5 percent increase in survival reported in this trial means 1,800 additional lives could potentially be saved each year from cardiac arrest,” Dr. Kudenchuk said. “We can and should strive to improve our treatments for this all-to-common event. We believe this study is a significant step in that direction.”

Adverse effects from the drugs were infrequent, and scientists are continuing to analyze findings from the trial to gain additional insight into its results.

Funding for this study was provided by NHLBI in partnership with the U.S. Army Medical Research & Material Command, the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Canada, and the American Heart Association. The study was presented at the American College of Cardiology 2016 Scientific Sessions in Chicago.

EMS agencies and receiving hospitals that participated in this trial are located in: Birmingham, Alabama; Vancouver, British Columbia; Dallas-Fort Worth; Seattle-King County; Milwaukee; Ottawa-OPALS Group, Ontario; Toronto; Portland, Oregon; San Diego; and Pittsburgh.

Part of the National Institutes of Health, the National Heart, Lung, and Blood Institute (NHLBI) plans, conducts, and supports research related to the causes, prevention, diagnosis, and treatment of heart, blood vessel, lung, and blood diseases; and sleep disorders. The Institute also administers national health education campaigns on women and heart disease, healthy weight for children, and other topics. NHLBI press releases and other materials are available online athttp://www.nhlbi.nih.gov.

SOURCE

http://www.nih.gov/news-events/news-releases/antiarrhythmic-drugs-found-beneficial-when-used-ems-treating-cardiac-arrest

Other related articles published in this Open Access Online Scientific Journal include the following: 

Antiarrhythmic drugs

http://pharmaceuticalintelligence.com/?s=Antiarrhythmic+drugs

A-Fib

http://pharmaceuticalintelligence.com/?s=a-fib

Electrophysiology N = 80

http://pharmaceuticalintelligence.com/?s=Electrophysiology

 

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Reporter: Aviva Lev-Ari, PhD, RN

Amiodarone Linked to Cancer Risk in Men

SOURCE:

Su V, et al. “Amiodarone and the risk of cancer: a nationwide population-based study” Cancer 2013; DOI: 10.1002/cncr.27881.

By Nancy Walsh, Staff Writer, MedPage Today

Published: April 08, 2013
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco
VIEW VIDEO
E. Kevin Heist, MD, PhD
MGH
Corrigan Minehan Heart Center

The risk of cancer was increased in men taking the antiarrhythmia drug amiodarone (Nexterone), particularly in those with extensive exposure to the drug, a retrospective study found.

Among men taking amiodarone, the risk for any cancer rose by almost 20% compared with the general population, with a standardized incidence ratio of 1.18 (95% CI 1.02 to 1.36, P=0.022), according to Chia-Jen Liu, MD, of National Yang-Ming University Hospital in Yilan, Taiwan, and colleagues.

And for men whose cumulative defined daily doses in a year exceeded 180, the risk was 46% higher (SIR 1.46, 95% CI 1.11 to 1.89,P=0.008), the researchers reported online inCancer.

Amiodarone has been associated with a number of potentially serious adverse events, including thyroid dysfunction, pulmonary fibrosis, and skin and thyroid malignancies, and a meta-analysis suggested a possible cancer link.

To examine the potential for an association with cancer, Liu and colleagues analyzed data from the Taiwanese National Health Insurance Research Database, identifying 6,418 patients who received amiodarone between 1997 and 2008.

More than half were men, the median age was 70, and median follow-up was 2.57 years.

Comorbidities were common, including hypertension (76%), heart failure (47%), chronic obstructive pulmonary disease (44%), and diabetes (39%).

During observation of almost 22,000 person-years, 280 cancers were identified.

Patients who had received amiodarone had a borderline increased risk of about 10% for all cancers (SIR 1.12, 95% CI 0.99 to 1.26, P=0.067), with a lag time of about 2 years.

Women did not appear to be at increased risk (SIR 99, 95% CI 0.79 to 1.23).

A possible explanation for the gender difference was that women clear the drug more quickly than men. Amiodarone has a half-life of almost 2 months and can accumulate in tissues, the researchers explained.

Among men, an elevated risk was seen for those ages 20 to 60 (SIR 1.67, 95% CI 1.07 to 2.48,P=0.025) and those over 80 (SIR 1.41, 95% CI 1.07 to 1.83, P=0.016).

Multivariate analysis identified these factors as being associated with increased risk:

  • Age: hazard ratio 1.04 (95% CI 1.03 to 1.06, P<0.001)
  • Male: HR 1.90 (95% CI 1.38 to 2.62, P<0.001)
  • Cirrhosis: HR 3.70 (95% CI 2.10 to 6.52, P<0.001)
  • Socioeconomic status: HR 0.63 (95% CI 0.45 to 0.87, P=0.006)
  • Cumulative daily doses: HR 1.001 for each additional dose (95% CI 1 to 1.002, P=0.022)

The researchers also analyzed risks when cumulative daily doses were stratified into tertiles. They found that patients in the intermediate and highest levels of cumulative doses had adjusted HRs of 1.70 (95% CI 1.02 to 2.84, P=0.042) and 1.98 (95% CI 1.22 to 3.22, P=0.006), respectively.

But they didn’t find any differences for specific types of cancer, including lung, thyroid, and skin.

That was a surprising finding, according to E. Kevin Heist, MD, PhD, of Massachusetts General Hospital Corrigan Minehan Heart Center in Boston, who was not involved in the study.

“Most carcinogens tend to increase risk of individual cancers,” Heist told MedPage Today.

“Even things like radiation that affect all cells of the body tend to increase individual cancer risks. So it does make one wonder why this is different than other known carcinogens, and whether in fact this is a real finding,” Heist said.

The researchers also pointed out that the numbers of individual cancers were small and the follow-up of 2.57 years may not have been long enough to detect actual differences.

Other limitations of the study included its cohort design, the unavailability of information on potential risk factors such as smoking, family history, and exposure to environmental toxins.

“Although extensive screenings for occult cancers in patients currently undergoing treatment with amiodarone appears to be impractical, we suggest that cancer events should be routinely reported in future amiodarone trials,” the researchers concluded.

For the time being, patients who need amiodarone should still receive it, but clinicians should exercise caution, Heist advised.

“I think the big messages are keep using it when you need to use it, but make sure you need it and make sure a safer alternative antiarrhythmic drug is not an option or has not been tried,” he said.

The study was supported by Taipei Veterans General Hospital.

The authors reported no financial conflicts.

Primary source: Cancer
Source reference:
Su V, et al. “Amiodarone and the risk of cancer: a nationwide population-based study” Cancer 2013; DOI: 10.1002/cncr.27881.

 

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