Featured Research

from universities, journals, and other organizations

No difference in brand name and generic drugs regarding thyroid dysfunction, study finds

Date:
July 11, 2011
Source:
Canadian Medical Association Journal
Summary:
There is no difference between brand-name and generic drug formulations of amiodarone -- taken to control arrhythmia -- in the incidence of thyroid dysfunction, according to a new study.

There is no difference between brand-name and generic drug formulations of amiodarone -- taken to control arrhythmia -- in the incidence of thyroid dysfunction, according to a study in CMAJ (Canadian Medical Association Journal).

Amiodarone, prescribed to control irregular heartbeats, is known for causing hypo- and hyper-thyroidism. Amiodarone is available in Canada in brand-name formulations as well as less costly generic versions. Generic formulations may be substituted if considered bioequivalent to the brand name drug. However, in some drugs there are concerns that generic formulas may be less effective or increase the number of adverse events.

Thyroid dysfunction occurs in one in five patients on amiodarone.

There is no information on the effects of brand-name versus generic versions of amiodarone on the incidence of thyroid dysfunction. Researchers from McGill University Health Centre and Jewish General Hospital, Montreal, Quebec; Western University of Health Sciences, Pomona, California; University of British Columbia, Vancouver, BC and the Institute for Clinical Evaluative Sciences in Toronto, Ontario sought to examine the incidence of thyroid dysfunction in patients taking brand name formulations of amiodarone compared with generic versions.

They looked at data on 60 220 patients aged 66 and older with atrial fibrillation taking amiodarone. Of these, 2804 (4.7%) used the brand-name formulation and 6278 (10.4%) took the generic formulation. There was no significant difference in rates of thyroid dysfunction between the two groups, measured in hospital admissions, visits to physicians for the condition or taking drugs for thyroid dysfunction.

"The incidence rate for thyroid dysfunction was estimated at 14.1 per 100 person-years, similar for both formulations," writes Dr. Louise Pilote, physician and researcher at the McGill University Health Center, with coauthors. "The incidence rates for hypothyroidism and hyperthyroidism per 100 person-years were comparable between brand-name and generic formulations, with hypothyroidism occurring more commonly than hyperthyroidism."

They caution that patients should be warned of the risks of amidarone when they begin the drug so they can recognize and report symptoms.

"We found no difference in the incidence of thyroid dysfunction between generic and brand-name formulations," conclude the authors. "The results from this study provide valuable information for both clinicians and policy makers concerning the prescription of brand name versus generic drugs."

In a related commentary, Dr. Aaron Kesselheim of Brigham and Women's Hospital in Boston states, "Decades of experience and numerous clinical studies suggest that patients and physicians can be confident in the bioequivalence of brand-name and generic drugs approved by Health Canada, the FDA or other similar regulatory authorities. In the rare circumstances where there is concern over interchangeability, such as for high-risk patients, it may be reasonable for physicians to take extra precautions, such as additional monitoring, when substitution occurs."


Story Source:

The above story is based on materials provided by Canadian Medical Association Journal. Note: Materials may be edited for content and length.


Journal References:

  1. Meytal A. Tsadok, Cynthia A. Jackevicius, Elham Rahme, Vidal Essebag, Mark J. Eisenberg, Karin H. Humphries, Jack V. Tu, Hassan Behlouli, Jennifer Joo, Louise Pilote. Amiodarone-induced thyroid dysfunction: brand-name versus generic formulations. Canadian Medical Association Journal, 2011; DOI: 10.1503/cmaj.101800
  2. Aaron S. Kesselheim. The backlash against bioequivalence and the interchangeability of brand-name and generic drugs. Canadian Medical Association Journal, 2011; DOI: 10.1503/cmaj.110808

Cite This Page:

Canadian Medical Association Journal. "No difference in brand name and generic drugs regarding thyroid dysfunction, study finds." ScienceDaily. ScienceDaily, 11 July 2011. <www.sciencedaily.com/releases/2011/07/110711131314.htm>.
Canadian Medical Association Journal. (2011, July 11). No difference in brand name and generic drugs regarding thyroid dysfunction, study finds. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2011/07/110711131314.htm
Canadian Medical Association Journal. "No difference in brand name and generic drugs regarding thyroid dysfunction, study finds." ScienceDaily. www.sciencedaily.com/releases/2011/07/110711131314.htm (accessed August 29, 2014).

Share This




More Health & Medicine News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Who Could Be Burnt by WHO's E-Cigs Move?

Who Could Be Burnt by WHO's E-Cigs Move?

Reuters - Business Video Online (Aug. 28, 2014) The World Health Organisation has called for the regulation of electronic cigarettes as both tobacco and medical products. Ciara Lee looks at the impact of the move on the tobacco industry. Video provided by Reuters
Powered by NewsLook.com
CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

Newsy (Aug. 28, 2014) CDC director Tom Frieden says the Ebola outbreak is even worse than he feared. But he also said there's still hope to contain it. Video provided by Newsy
Powered by NewsLook.com
How A 'Rule Of Thumb' Could Slow Down Drinking

How A 'Rule Of Thumb' Could Slow Down Drinking

Newsy (Aug. 28, 2014) A study suggests people who follow a "rule of thumb" when pouring wine dispense less than those who don't have a particular amount in mind. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins