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Mixing large doses of both acetaminophen painkiller and caffeine may increase risk of liver damage

WASHINGTON, Sept. 26 2007 — Consuming large amounts of caffeine while taking acetaminophen, one of the most widely used painkillers in the United States, could potentially cause liver damage, according to a preliminary laboratory study reported in the Oct. 15 print issue of ACS’ Chemical Research in Toxicology, a monthly journal. The toxic interaction could occur not only from drinking caffeinated beverages while taking the painkiller but also from using large amounts of medications that intentionally combine caffeine and acetaminophen for the treatment of migraine headaches, menstrual discomfort and other conditions, the researchers say.

Health experts have warned for years that consuming excess alcohol while taking acetaminophen can trigger toxic interactions and cause liver damage and even death. However, this is the first time scientists have reported a potentially harmful interaction while taking the painkiller with caffeine, the researchers say.

While the studies are preliminary findings conducted in bacteria and laboratory animals, they suggest that consumers may want to limit caffeine intake — including energy drinks and strong coffee — while taking acetaminophen.

Chemist Sid Nelson, Ph.D., and colleagues, of the University of Washington in Seattle, tested the effects of acetaminophen and caffeine on E. coli bacteria genetically engineered to express a key human enzyme in the liver that detoxifies many prescription and nonprescription drugs. The researchers found that caffeine triples the amount of a toxic byproduct, N-acetyl-p-benzoquinone imine (NAPQI), that the enzyme produces while breaking down acetaminophen. This same toxin is responsible for liver damage and failure in toxic alcohol-acetaminophen interactions, they say.

In previous studies, the same researchers showed that high doses of caffeine can increase the severity of liver damage in rats with acetaminophen-induced liver damage, thus supporting the current finding.

“People should be informed about this potentially harmful interaction,” Nelson says. “The bottom line is that you don’t have to stop taking acetaminophen or stop taking caffeine products, but you do need to monitor your intake more carefully when taking them together, especially if you drink alcohol.”

Nelson points out that the bacteria used in the study were exposed to ‘megadoses’ of both acetaminophen and caffeine, much higher than most individuals would normally consume on a daily basis. Most people would similarly need to consume unusually high levels of these compounds together to have a dangerous effect, but the toxic threshold has not yet been determined, he says.

Certain groups may be more vulnerable to the potentially toxic interaction than others, Nelson says. This includes people who take certain anti-epileptic medications, including carbamazepine and phenobarbital, and those who take St. John’s Wort, a popular herbal supplement. These products have been shown to boost levels of the enzyme that produces the toxic liver metabolite NAPQI, an effect that will likely be heightened when taking both acetaminophen and caffeine together, he says.

Likewise, people who drink a lot of alcohol may be at increased risk for the toxic interaction, Nelson says. That’s because alcohol can trigger the production of yet another liver enzyme that produces the liver toxin NAPQI. The risks are also higher for those who take large amounts of medications that combine both acetaminophen and caffeine, which are often used together as a remedy for migraine headaches, arthritis and other conditions.

The researchers are currently studying the mechanism by which this toxic interaction occurs and are considering human studies in the future, they say. The National Institutes of Health funded the initial animal and bacterial studies.

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— Mark T. Sampson

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Contents of this release are strictly embargoed by the ACS, which has sole authority to alter the release time. Wire service stories must carry the embargo time, and wire stories on the press release topic may not be distributed more than 24 hours before that time. Solely to solicit expert comment, news media may show relevant parts of this document, and the paper to which it refers, to independent specialists. However, they must ensure in advance the embargo conditions will be honored. The research in this press release is from a copyrighted publication, and stories must credit the journal by name. Anyone using advance information for stocks or securities dealing may be guilty of insider trading under the federal Securities Exchange Act of 1934. For questions or assistance, please use the news media contact, above.

Paper:
“Cooperative Binding of Acetaminophen and Caffeine within the P450 3A4 Active Site,” tx7000702
Print publication date: Oct. 15, 2007
ASAP (online) date: 9-26-07

Contact: Michael Bernstein
m_bernstein@acs.org
202-872-4400
American Chemical Society

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September 26, 2007 Posted by | Acetaminophen and Caffeine, American Chemical Society, Global Health Vision, Global News, Health, News, Preventive Medicine, RSS Feed, WASHINGTON | 2 Comments

Vitamin D supplements may offer cheap and effective immune system boost against TB

Contact: Craig Brierley
c.brierley@wellcome.ac.uk
44-207-611-7329
Wellcome Trust

Scientists have shown that a single 2.5mg dose of vitamin D may be enough to boost the immune system to fight against tuberculosis (TB) and similar bacteria for at least 6 weeks. Their findings came from a study that identified an extraordinarily high incidence of vitamin D deficiency amongst those communities in London most at risk from the disease, which kills around two million people each year.

The research, funded by the Wellcome Trust, the Department of Environmental Health at Newham Council and Newham University Hospital NHS Trust Respiratory Research Fund, is published online in the American Journal of Respiratory and Critical Care Medicine.

Whilst a diet of oily fish can provide some vitamin D, the main source of the body’s vitamin D comes from exposing the skin to sunlight. In Britain, however, the amount of sunlight is usually insufficient to make vitamin D in the skin between October and April, and much of the population becomes deficient during the winter and spring.

Researchers from Queen Mary’s School of Medicine and Dentistry, London, and the Wellcome Trust Centre for Research in Clinical Tropical Medicine, Imperial College London, studied patients at Newham University Hospital and Northwick Park Hospital in London who had been exposed to TB. They found that over 90% of such patients had a vitamin D deficiency.

Vitamin D was used to treat TB in the pre-antibiotic era, when special sanatoria were built in sunny locations, such as the Swiss Alps. But until now, no study has evaluated the effect of vitamin D supplementation on immunity to mycobacteria, the family of bacteria that cause TB.

The researchers performed a randomised control trial on a group of volunteers who were given either a 2.5mg supplement or a placebo. Samples of the volunteers’ blood were then tested in Dr Robert Wilkinson’s Wellcome Trust-funded laboratory at Imperial College, to see whether the supplement affected the immune system’s ability to withstand infection by mycobacteria.

“We found that a single large dose of vitamin D was sufficient to enhance a person’s immunity to the bacteria,” says Dr Adrian Martineau from Imperial College London, who co-ordinated the study. “This is very significant given the high levels of vitamin D deficiency in people at the highest risk of TB infection, and shows that a simple, cheap supplement could make a significant impact on the health of people most at risk from the disease.”

According to the Health Protection Agency, the incidence of TB in the UK is increasing, with around 8,000 new cases a year. Cases in the UK are predominantly confined to the major cities and about 40 per cent of all cases are in London. TB is also a major global problem: an estimated one-third of the world’s population – nearly two billion people – are infected. Nine million people a year develop the active disease worldwide, which kills two million each year.

“Most cases of TB in London arise from people who have already become infected with the bacteria but in whom it lies latent,” says Professor Chris Griffiths from Queen Mary’s School of Medicine and Dentistry. “Our results indicate that vitamin D supplementation may prevent reactivation of latent TB. Identifying people with latent TB and providing supplements could be an important strategy for tackling the disease.”

Treatment is both very cheap – about 60p per dose or 10p per week – and safe. Vitamin D supplements could be prescribed for patients with or at risk of latent TB through GP surgeries.

Dr Martineau points out: “Our work adds to the growing evidence that vitamin D may have a wide range of important health benefits, including preventing falls and fractures and reducing risk of cancer and diabetes, as well as boosting the immune system against infection. Population-wide supplementation needs to be considered by public health planners.”

“Milk and orange juice could be fortified with vitamin D, as in the US and Canada,” he says. “At present only margarine is supplemented in the UK, and recent studies show that this is not an effective way to prevent vitamin D deficiency.”

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May 15, 2007 Posted by | Alberta, Baltimore, Calgary, Global, Global Health Vision, Global News, News, News Australia, News Canada, News UK, News US, Preventive Medicine, TB, Tuberculosis, Washington DC, Wellcome Trust, World News | Leave a comment