Friday, February 13, 2015
Does oseltamivir work and does it have side effects?
The flu season has really gotten into gear now with 46 of our 50 states reporting widespread influenza activity. Influenza is a virus that infects the respiratory tract, causing sore throat, runny nose, fever and cough. Rarely people with the flu will have nausea, vomiting and diarrhea, but this is not “stomach flu,” which is a term some of us use to describe any one of a number of viruses that give us intestinal symptoms. Influenza is the one where you hurt all over, you have a high fever and cold symptoms, then you start coughing and you can barely get out of bed for days. Sometimes it's milder than that, but it can also be more severe, affecting brain function and sometimes requiring oxygen or life support with a ventilator. It also kills people, on the order of about a half a million worldwide every year, either directly by the destructive effects of the virus or by setting the stage for a devastating bacterial pneumonia.
Flu is very contagious. A person with the flu can spread it to others for 1-2 weeks, and it frequently runs through whole schools, resulting in as many as 1 in 3 children being absent from classes. The very best way to reduce the spread of flu is to have people with the flu stay away from people without the flu. Hand washing is also good. Epidemic flu usually lasts for about 13 weeks each year, tapering off toward the end of the season, and usually it's pretty much gone by March. This year we are starting with influenza A, which is usually the most severe type, and the genetic signature is not one that is well covered by the present flu vaccine.
The Centers for Disease Control (CDC) posted an article detailing the present flu situation. They estimate that the vaccine is 23% effective, but that is based on an odds ratio calculated by comparing a group of sick people who did or did not have the flu when tested and looking at whether or not they were vaccinated. What they mean is that if you are sick enough to be tested for the flu, you are 23% less likely to actually have the influenza virus if you got the vaccination. But the vaccine is still recommended because there will be influenza B coming around later, as well as the non-seasonal flu, H1N1, which should be covered by the vaccine. There is also a chance that the influenza A you are exposed to could be one that has not genetically drifted, which might mean the vaccine would make you more immune to it.
This year's flu is a pretty nasty one, with many people getting sick enough to need hospitalization. It is not the most terrible we have seen, and is similar in how sick it makes people to the 2012-2013 season, 2 years ago. Because the vaccine is less effective this year, though, the CDC is recommending that physicians be very generous about prescribing 1 of the 2 influenza antiviral medications. These are oseltamivir (Tamiflu) and zanamivir (Relenza). Oseltamivir (which is not available as a generic) is a capsule or liquid which is dosed twice daily and costs a bit over $100 for a 5 day course. Zanamivir (also still on patent) costs a little less and is inhaled, twice daily, and is contraindicated in asthmatics since it can make them wheeze. The Cochrane Collaboration, an organization which reviews scientific data in an unbiased fashion, says that neither drug does much for healthy people infected with the influenza virus, and there is no really good data to determine if it helps people who aren't otherwise healthy or who are desperately ill with it. They both tend to make the symptoms a little less severe and shorten the duration of illness by half a day to 1 day. I have been prescribing them generously for years to my patients with the flu, since I know how nasty it is and have always figured that they could use all the help they could get.
A few days ago a friend asked me if I had heard anything about mental effects of Tamiflu. She said that an acquaintance of hers had a son who had committed suicide after being started on it. His girlfriend had just left him, but he was a very psychologically stable person, and this wasn't like him. She said that she had heard that the drug could make people mentally unstable. I thought that it sounded like hogwash, so I checked my handy dandy iPhone Epocrates app and found that behavioral effects and self-injury were quite high on the list of serious side effects. Today, I looked further into it and found that in Japan, where Tamiflu is used more commonly than in the U.S., they reported quite a few cases of psychological side effects, including delirium, primarily in children and adolescents within the first 48 hours that they took the drug, with something like 70 deaths. The Food and Drug Administration reviewed side effects, especially during the 2009 pandemic when Tamiflu was widely used, and found that there were some psychological side effects reported, but pretty rarely. There were also some severe skin reactions, even resulting in death. There were more case reports, including a girl who had manic depressive symptoms that resolved only after a few months, out of South Korea. Tamiflu also makes about 1 in 9 patients vomit.
In general oseltamivir (Tamiflu) is safe and the influenza vaccine is safe. They are also both somewhat, though not gloriously, effective. Both are lucrative for the companies that make them. The flu is a huge public health issue, causing death and disability and work and school loss, and it repeats itself yearly, with varying intensity. Because control of the flu, even shortening illness by a day or decreasing transmission just a bit, is so very important on a population level it is likely that the down side to an individual will tend to be minimized. As an individual and as a member of a human herd, I will continue to get yearly flu vaccines and nudge my dear ones to do the same. If I wake up feeling like I got hit by a truck and then nanobots have attacked my mucus membranes with sandpaper I will probably take one of the anti-flu drugs (but maybe zanamivir, since it is cheaper and probably won't make me jump off a balcony.) These are decisions, though, that individual patients should make after being fully informed of both effectiveness and potential side effects.
Janice Boughton, MD, ACP Member, practiced in the Seattle area for four years and in rural Idaho for 17 years before deciding to take a few years off to see more places, learn more about medicine and increase her knowledge base and perspective by practicing hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling. Disturbed by various aspects of the practice of medicine that make no sense and concerned about the cost of providing health care to every American, she blogs at Why is American Health Care So Expensive?, where this post originally appeared.
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Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:
Albert Fuchs, MD, FACP, graduated from the University of California, Los Angeles School of Medicine, where he also did his internal medicine training. Certified by the American Board of Internal Medicine, Dr. Fuchs spent three years as a full-time faculty member at UCLA School of Medicine before opening his private practice in Beverly Hills in 2000.
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Amanda Xi, ACP Medical Student Member, is a first-year medical student at the OUWB School of Medicine, charter class of 2015, in Rochester, Mich., from which she which chronicles her journey through medical training from day 1 of medical school.
Ira S. Nash, MD, FACP, is the senior vice president and executive director of the North Shore-LIJ Medical Group, and a professor of Cardiology and Population Health at Hofstra North Shore-LIJ School of Medicine. He is Board Certified in Internal Medicine and Cardiovascular Diseases and was in the private practice of cardiology before joining the full-time faculty of Massachusetts General Hospital.
Zackary Berger, MD, ACP Member, is a primary care doctor and general internist in the Division of General Internal Medicine at Johns Hopkins. His research interests include doctor-patient communication, bioethics, and systematic reviews.
Controversies in Hospital
Run by three ACP Fellows, this blog ponders vexing issues in infection prevention and control, inside and outside the hospital. Daniel J Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Iowa City, IA, with a focus on understanding why infections occur in the hospital and ways to prevent these infections, and sees patients in the inpatient and outpatient settings. Eli N. Perencevich, MD, ACP Member, is an infectious disease physician and epidemiologist in Iowa City, Iowa, who studies methods to halt the spread of resistant bacteria in our hospitals (including novel ways to get everyone to wash their hands).
db's Medical Rants
Robert M. Centor, MD, FACP, contributes short essays contemplating medicine and the health care system.
Suneel Dhand, MD, ACP Member
Suneel Dhand, MD, ACP Member, is a practicing physician in Massachusetts. He has published numerous articles in clinical medicine, covering a wide range of specialty areas including; pulmonology, cardiology, endocrinology, hematology, and infectious disease. He has also authored chapters in the prestigious "5-Minute Clinical Consult" medical textbook. His other clinical interests include quality improvement, hospital safety, hospital utilization, and the use of technology in health care.
Juliet K. Mavromatis, MD, FACP, provides a conversation about health topics for patients and health professionals.
Dr. Mintz' Blog
Matthew Mintz, MD, FACP, has practiced internal medicine for more than a decade and is an Associate Professor of Medicine at an academic medical center on the East Coast. His time is split between teaching medical students and residents, and caring for patients.
Toni Brayer, MD, FACP, blogs about the rapid changes in science, medicine, health and healing in the 21st century.
Vineet Arora, MD, FACP, is Associate Program Director for the Internal Medicine Residency and Assistant Dean of Scholarship & Discovery at the Pritzker School of Medicine for the University of Chicago. Her education and research focus is on resident duty hours, patient handoffs, medical professionalism, and quality of hospital care. She is also an academic hospitalist.
John H. Schumann, MD, FACP, provides transparency on the workings of medical practice and the complexities of hospital care, illuminates the emotional and cognitive aspects of caregiving and decision-making from the perspective of an active primary care physician, and offers behind-the-scenes portraits of hospital sanctums and the people who inhabit them.
Ryan Madanick, MD, ACP Member, is a gastroenterologist at the University of North Carolina School of Medicine, and the Program Director for the GI & Hepatology Fellowship Program. He specializes in diseases of the esophagus, with a strong interest in the diagnosis and treatment of patients who have difficult-to-manage esophageal problems such as refractory GERD, heartburn, and chest pain.
Mike Aref, MD, PhD, FACP, is an academic hospitalist with an interest in basic and clinical science and education, with interests in noninvasive monitoring and diagnostic testing using novel bedside imaging modalities, diagnostic reasoning, medical informatics, new medical education modalities, pre-code/code management, palliative care, patient-physician communication, quality improvement, and quantitative biomedical imaging.
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David Katz, MD
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Richard Just, MD, ACP Member, has 36 years in clinical practice of hematology and medical oncology. His blog is a joint publication with Gregg Masters, MPH.
Kevin Pho, MD, ACP Member, offers one of the Web's definitive sites for influential health commentary.
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Alexander M. Djuricich, MD, FACP, is the Associate Dean for Continuing Medical Education (CME), and a Program Director in Medicine-Pediatrics at the Indiana University School of Medicine in Indianapolis, where he blogs about medical education.
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Technology in (Medical)
Neil Mehta, MBBS, MS, FACP, is interested in use of technology in education, social media and networking, practice management and evidence-based medicine tools, personal information and knowledge management.
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Janice Boughton, MD, FACP, practiced internal medicine for 20 years before adopting a career in hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling.
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Also known as the Green Journal, the American Journal of Medicine publishes original clinical articles of interest to physicians in internal medicine and its subspecialities, both in academia and community-based practice.
A collaborative medical blog started by Neil Shapiro, MD, ACP Member, associate program director at New York University Medical Center's internal medicine residency program. Faculty, residents and students contribute case studies, mystery quizzes, news, commentary and more.
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The Public Library of Science's open access materials include a blog.
One of the most popular anonymous blogs written by an emergency room physician.