What does the new Tamiflu data really tell us?

Influenza Treatment, Adolescent
Does Tamiflu have any meaningful effects on the prevention or treatment of influenza? Considering the drug’s been on the market for almost 15 years, and is widely used, you should expect this question has been answered after 15 flu seasons. Answering this question from a science-based perspective requires three steps: Consider prior probability, be systematic in the approach, and get all the data. It’s the third step that’s been (until now) impossible with Tamiflu: Some data was unpublished. In general, there’s good evidence to show that negative studies are less likely to be published than positive studies. Unless unpublished studies are included, systematic reviews are more likely to miss negative data, which means there’s the risk of bias in favor of an intervention.

The absence of a full data set on Tamiflu (oseltamivir) and the other neuraminidase inhibitor Relenza (zanamivir) became a rallying point for BMJ and the AllTrials campaign, which seeks to enhance the transparency and accessibility of clinical trials data by challenging trial investigators to make all evidence freely available. (Reforming and enhancing access to trial data was one of the most essential changes recommended by Ben Goldacre in his book, Bad Pharma.) In 2009, Tamiflu’s manufacturer, Hoffman-La Roche committed to making the Tamiflu data set available to investigators. Now after four years of back-and-forth between BMJ, investigators, and Roche, the full clinical trials data set has been made freely available. An updated systematic review was published today in BMJ (formerly The British Medical Journal), entitled “Oseltamivir for influenza in adults and children: systematic review of clinical study reports and summary of regulatory comments.” This will be a short post covering the highlights. As the entire study and accompanying data are freely available, I’ll await continued discussion in the comments. Continue reading

Could prenatal use of Tylenol cause ADHD?

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Pharmacists are among the most accessible of health professionals, and so we receive a lot of questions from the public. No appointment required, and the advice is free. Among the most frequent sources of questions are women seeking advice on drug use in pregnancy. This is an area where some health professionals are reluctant to tread. Some prefer to redirect all of these questions to physicians. But physicians are not always easily accessible, and few want to make an appointment just to ask what appears to be a simple question: Is it safe, or not? Admittedly, addressing questions about drug use in pregnancy can be challenging. There are no randomized controlled trials we can look to — there’s only messier, less definitive data. Our responses are filled with cautious hedging about risk and benefit, describing what we know (and don’t know) about fetal effects. In the pharmacy, one of the most common questions from pregnant women is about the use of acetaminophen (aka paracetamol aka APAP), more commonly known by the brand name Tylenol. Google “Tylenol and pregnancy” and you get 4.8 million results. Which source should you trust? Continue reading

Naturopathy versus Science: Seasonal Allergy Edition

tilting at windmills

I glanced at my pharmacy license recently, and noticed I became a licensed pharmacist almost exactly twenty years ago. Two decades seems like a long time to do pretty much anything, yet I can still vividly recall some of the patients I encountered early in my career, working evenings in a retail pharmacy that drew heavily on the alternative medicine crowd. It was the first pharmacy I’d ever seen that sold products like homeopathy, detox kits, salt lamps, ear candles, and magnetic foot pads. And the customers were just as unorthodox. There were some that told me they manipulated their own pH, and others that insisted any prescription drug was designed to kill. And there was a huge clientele that relied on the pharmacy for their “bioidentical” hormones. It was an instructive learning experience, as it was as far from the science of pharmacy school as you could expect to find in a place that still called itself a pharmacy. One of the really interesting aspects of that pharmacy was the enormous supply of vitamins and supplements for sale. It stretched over multiple aisles and even back into the dispensary, where there were some brands kept behind the counter. This wasn’t for any regulatory reason – it was because these were the “naturopathic” supply, the brands often recommended by naturopaths. In order for this pharmacy to sell them they had to keep the products behind the counter, presumably to grant these supplements a veneer of medical legitimacy. These were “special”, and they had the prices to prove it. Continue reading

Mozi-Q Fools The Dragons

Mozi-Q is a product developed and sold by Canadian company Xerion Dispensary, and marketed as an insect repellant. But it’s effectively just a sugar pill. Mozi-Q is a “homeopathic” remedy which means that it has no active or medicinal ingredients. Homeopathy is a disproved alternative medicine system where the “remedies” are based on substances that are repeatedly diluted to the point that few, if any, molecules of the any original ingredients actually remain. Not surprisingly, there is no published evidence to demonstrate Mozi-Q works as an insect repellant. For the back story on how this product came to be approved by Health Canada despite a lack of evidence, see the older posts When homeopathy is approved as an insect repellent, there’s a serious regulatory problem and the follow-up, Mozi-Q – “Insect repellent you eat”. But does it work? In short, Mozi-Q is approved for sale only because it is considered a “Natural Health Product” by Health Canada. Under these circumstances, there are effectively no evidence standards required to market a product with medicinal or therapeutic claims.  Continue reading

The Diet Fix: A Science-Based Weight Loss Guide

The-Diet-Fix-427x640Diets fail. Not just often, but almost always—90% of the time. If diets worked we wouldn’t have a worldwide obesity problem. And obesity is a problem that needs to be solved. The prevalence of obesity has doubled since 1980. As a public health issue, there are few determinants of illness that are more destructive, as obesity contributes to the growing rates of diabetes, heart disease, and even cancer. There’s no “one true cause” of all illness, but obesity comes pretty close. When people ask me for the single most important thing they can do for their health, my advice (after quitting smoking) is to (1) ensure you keep your weight under control and (2) exercise in any way possible.

Despite its tremendous impact on health, I’ve only blogged about obesity in an indirect way—by pointing out what doesn’t work. Dr. Oz is my perpetual source of bad health information with his regular promotion of bogus “weight loss” supplements like the green coffee bean “miracle”. I’ve also criticized eating programs like the fads of “Eating Clean”, gluten “intolerance”, or harmful diet delusions like “detox”. It’s the typical skeptical science blogger approach—spot pseudoscience, debunk it, and hope you did something good. But none of my posts have focused on what one should do—just what you shouldn’t. Over at Science-Based Medicine (where I also blog) Dr. Mark Crislip recently commented that what science-based medicine advocates support manifests in what we oppose. He’s right, because that’s the easy approach. Using the principles of science-based medicine, there’s an awful lot to oppose in the current writing and popular opinion on how to treat obesity. And my professional advice in the role of a pharmacist has been limited to steering people away from supplements, and then giving some basic advice about dietary planning. Anecdotes and platitudes. I admit that I’ve told patients to “eat less and exercise more”. I haven’t seen pharmacists do much more, though I like to think that pharmacists can and should be playing a much larger part in obesity management and treatment.
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False “Balance” and an Appeal to Nature in the Globe and Mail

Science vs. BS

One of the encouraging shifts I’ve seen in health journalism over the past few years is the growing recognition that antivaccine sentiment is antiscientific at its core, and doesn’t justify false “balance” in the media. There’s no reason to give credibility to the antivaccine argument when their positions are built on a selection of discredited and debunked tropes. This move away from false balance and towards a more accurate reflection of the evidence seems to have started with the decline and disgrace of Andrew Wakefield and his MMR fraud. And there is now no question that antivaccine sentiment has a body count: Simply look at the resurgence of preventable communicable disease. Today, antivaccinationists are increasingly recognized for what they are – threats to public health. It seems less common today (versus just 5 years ago) that strident antivaccine voices are given either air time or credibility in the media.

But false balance on topics like influenza can occur without giving a voice to groups like antivaccinationists. A more subtle technique to shift perceptions is both widespread and hard to detect, unless you’re aware of it: the naturalistic fallacy, known more accurately as the appeal to nature. In short, it means “It’s natural so it’s good” with the converse being “unnatural is bad.” In general, the term “natural” has a positive perception, so calling a product (or a health intervention) “natural” is implying goodness. The appeal to nature is so common that you may not even recognize it as a logical fallacy. Unnatural can be good, and natural can be bad: Eyeglasses are unnatural. And cyanide is natural. Natural doesn’t mean safe or effective. But the appeal to nature is powerful, and it’s even persuasive to governments. If we believe that health interventions and treatments should be evaluated on their merits, rather than whether or not they’re “natural”, then decisions to regulate “natural” products differently than the “unnatural” ones (like drugs) makes little sense. Yet the Dietary Supplement Health and Education Act was a legislative appeal to nature, introducing a different regulatory and safety standard for a group of products while drawing a fallacious distinction with “unnatural” products like drugs. Canada fell for the appeal to nature too: It has the Natural Health Products Regulations which entrenched a lowered bar for efficacy and safety for anything a manufacturer can demonstrate is somehow “natural”. Continue reading

Is there anything the Natural Health Products Directorate won’t approve? The Antioxidant Edition

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Regulators like Health Canada have tremendous power. They alone decide whether a drug or health product can be legally sold in Canada. With that power they have the authority to compel manufacturers to generate data to support their health claims, and they have the final word on the marketing statements a manufacturer can make about their product. If you don’t satisfy their requirements, you may not sell your product in Canada. Health Canada claims to have a rigorous review process, and they assure Canadians that  their approval means (in their words) that a product is “safe, effective, and of high quality.” The system is designed for consumer protection purposes – regulations and rules for companies have developed over decades based  in part on regulatory disasters like the thalidomide tragedy. So when you see a product that is approved by Health Canada that claims “Helps the body to metabolize fats and proteins”, then you might expect that claim to be backed by good scientific evidence. You’d be wrong. Regrettably, Health Canada has effectively eliminated regulatory requirements for anything that can be called a “Natural Health Product”. It’s a regulatory double standard that has allowed hundreds of useless and sometimes potentially dangerous products on to the Canadian marketplace. Continue reading