(Press-News.org) 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) (pre-embargo link only) http://www.cmaj.ca/site/embargo/cmaj101800.pdf.
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 (pre-embargo link only) http://www.cmaj.ca/site/embargo/cmaj110808.pdf, 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."
### END
No difference in brand name and generic drugs regarding thyroid dysfunction
2011-07-12
ELSE PRESS RELEASES FROM THIS DATE:
Alcohol consumption guidelines inadequate for cancer prevention
2011-07-12
Current alcohol consumption guidelines are inadequate for the prevention of cancer and new international guidelines are needed, states an analysis in CMAJ (Canadian Medical Association Journal) (pre-embargo link only) http://www.cmaj.ca/site/embargo/cmaj110363.pdf.
Guidelines in some countries are not currently based on evidence for long-term harm. Most guidelines are based on studies that assessed the short-term effects of alcohol, such as social and psychological issues and hospital admissions, and were not designed to prevent chronic diseases. As well, in some countries, ...
July/August 2011 Annals of Family Medicine tip sheet
2011-07-12
Power and Potential of Mobile Sensing Devices to Improve Health Care
Researchers from Dartmouth offer a provocative glimpse into the possibilities of wireless mobile technology to measure elderly patients' physical activity and social interactions and improve detection of changes in their health. Sensors on a waist-mounted wireless mobile device worn by eight patients aged 65 and older continuously measured patients' time spent walking level, up or down an elevation, and stationary (sitting or standing), and time spent speaking with one or more other people. Researchers ...
Bladder cancer patients rarely receive recommended care
2011-07-12
A new study has found that almost all patients with high-grade noninvasive bladder cancer do not receive complete care as recommended by current guidelines. Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the study indicates that efforts are needed to identify and overcome barriers to providing optimal care to patients with bladder cancer.
High-grade noninvasive bladder cancer has up to a 70 percent chance of recurring after treatment and up to a 50 percent chance of progressing to a more invasive tumor. Effective treatment for ...
Genetic switch for limbs and digits found in ancient fish
2011-07-12
Genetic instructions for developing limbs and digits were present in primitive fish millions of years before their descendants first crawled on to land, researchers have discovered.
Genetic switches control the timing and location of gene activity. When a particular switch taken from fish DNA is placed into mouse embryos, the segment can activate genes in the developing limb region of embryos, University of Chicago researchers report in Proceedings of the National Academy of Sciences. The successful swap suggests that the recipe for limb development is conserved in species ...
A classic instinct -- salt appetite -- is linked to drug addiction
2011-07-12
Durham, N.C., U.S. and Melbourne, Australia -- A team of Duke University Medical Center and Australian scientists has found that addictive drugs may have hijacked the same nerve cells and connections in the brain that serve a powerful, ancient instinct: the appetite for salt.
Their rodent research shows how certain genes are regulated in a part of the brain that controls the equilibrium of salt, water, energy, reproduction and other rhythms – the hypothalamus. The scientists found that the gene patterns activated by stimulating an instinctive behavior, salt appetite, ...
Landscape change leads to increased insecticide use in the Midwest
2011-07-12
MADISON - The continued growth of cropland and loss of natural habitat have increasingly simplified agricultural landscapes in the Midwest. A Great Lakes Bioenergy Research Center (GLBRC) study concluded that this simplification is associated with increased crop pest abundance and insecticide use, consequences that could be tempered by perennial bioenergy crops.
While the relationship between landscape simplification, crop pest pressure, and insecticide use has been suggested before, it has not been well supported by empirical evidence. This study, published online in ...
Regional system to cool cardiac arrest patients improves outcomes
2011-07-12
A broad, regional system to lower the temperature of resuscitated cardiac arrest patients at a centrally-located hospital improved outcomes, according to a study in Circulation: Journal of the American Heart Association.
Cooling treatment, or therapeutic hypothermia, is effective yet underused, researchers said.
A network of first responders, EMS departments and more than 30 independent hospitals within 200 miles of Minneapolis, Minn., and Abbott Northwestern Hospital collaborated to implement the protocol.
"We've shown that a fully integrated system of care, from ...
Obstructive sleep apnea linked to blood vessel abnormalities
2011-07-12
Obstructive sleep apnea may cause changes in blood vessel function that reduces blood supply to the heart in people who are otherwise healthy, according to new research reported in Hypertension: Journal of the American Heart Association.
However, treatment with 26 weeks of continuous positive airway pressure (CPAP) improved study participants' blood supply and function.
Obstructive sleep apnea, which causes periodic pauses in breathing during sleep, affects about 15 million adults in the United States, according to the American Heart Association. The sleep disorder ...
Nearly all patients with high-grade bladder cancer do not receive guideline-recommended care
2011-07-12
A study at UCLA's Jonsson Comprehensive Cancer Center found that nearly all patients with high-grade, non-invasive bladder cancer are not receiving the guideline-recommended care that would best protect them from recurrence, a finding that researchers characterized as alarming.
In fact, out of the 4,545 bladder cancer patients included in the study, only one received the comprehensive care recommended by the American Urology Association and the National Comprehensive Cancer Network.
Receiving the recommended comprehensive care for high-grade bladder cancer is critical ...
Do-it-yourself brain repair following stroke
2011-07-12
Stroke is a leading cause of long-term disability and death in the United States. A team of researchers — led by Gregory Bix, at Texas A&M College of Medicine, College Station — has identified a way to exploit one of the brain's self-repair mechanisms to protect nerve cells and enhance brain repair in rodent models of stroke. The authors suggest that this approach could provide a nontoxic treatment for stroke.
The most common form of stroke (ischemic stroke) occurs when a blood vessel that brings oxygen and nutrients to the brain becomes clogged, for example with a blood ...