I generally enthusiastically adopt new technologies, but I exercise caution with new medicines. Unless you are emailing while driving, a Blackberry is unlikely to kill you. In contrast, medicines can be dangerous.
A recent example is varenicline, or Chantix, a novel medicine that held enormous promise to get smokers to quit. It was approved by the FDA in 2006. In a study reported in the Journal of the American Medical Association (JAMA), 44% of those on Chantix had quit by the end of 12 weeks versus 18% of those on placebo. By the end of a year, 22% who had taken Chantix were still not smoking versus 8% who had taken placebo. Then, reports began to appear of suicidal and homicidal behavior. The FDA issued a warning in February 2008.
This raises several questionsÂ—among the most urgent, how did the FDA miss this risk when approving the drug? Here are some points to consider about how this happened:
- The JAMA study included a total of 1,025 patients. Compare this to the 150,000 new prescriptions that were being filled per week at ChantixÂ’s peak in 2008. We see this all of the time. Drugs are studied on a relatively small number of patients and then when approved, they are prescribed to a much bigger number of people. The more experience we have with a medication (or combination of medicines) the more we learn, especially about rare side effects.
- The Chantix study was funded completely by the manufacturer. One hopes that all of the data were accurately reported, but many people have raised concerns about the reliability of research done by pharmaceutical companies.
- As is often the case, Chantix was studied in relatively healthy people Â– who may not be those most apt to have side effects or drug interactions. None of the patients in the original Chantix study had serious mental health problems, or alcohol or drug abuse. Patients with many serious illnesses were not allowed into the study.
The FDA isnÂ’t the only group minding the store. The Institute for Safe Medication Practice (ISMP) actually has the most extensive report on Chantix and its risks (http://www.ismp.org/docs/vareniclineStudy.asp). They brought their attention to Chantix while they monitored reports of drug reactions submitted to the FDA. By the fourth quarter of 2007, the FDA was getting more reports on Chantix than on any other medicine prescribed in the country. The ISMP report is currently the only source of information on these reports to the FDA.
So, is that the whole story? I learned the hard way that it is not. One of my patients has struggled for years to quit smoking. After many failed attempts with every strategy we could think of, we agreed to try Chantix. I warned her extensively of the behavioral risks, and we recruited her sister to watch vigilantly for any sign of behavioral or mood change.
The good news was that she was psychiatrically fine and she lost her desire to smoke within days of her first pill. The bad news is that her diabetes raged out of control, bringing her to the hospital twice within three weeks of taking her first Chantix pill. Happily, when the drug had cleared her system, her diabetes came back under control.
The diabetes specialists were skeptical that Chantix had a role. After all, diabetes and high blood sugar are not mentioned anywhere in the physician prescribing information for Chantix. There isnÂ’t a single report of this in the medical literature. To my shock, however, it turns out that high blood sugar is the number one issue that has been reported to the FDA as a consequence of Chantix. Unfortunately, most doctors are unaware of this potential complication, though it is noted in the report from the ISMP.
So, what can you do as a patient and consumer? First, be careful about new medicines. Talk to your doctor about the risks and benefits, and understand that risks are likely not fully known with newly approved medicines. If you do experience a side effect while taking a new medicine, talk to your doctor, even if it isnÂ’t listed in the information you read about the drug. For a common problem like headache or diarrhea, it can be really hard to tell if the problem is from the medicine or not. In these cases it might make sense to stop the medication (with your doctorÂ’s approval), wait until your symptoms go away, and then restart the medication to see if the symptoms come back. Finally, if a medicine you take does cause a previously unknown, serious side effect, either you or your doctor should report it to the FDA at www.fda.gov/medwatch. It turns out that of the more than 3,000 reports on Chantix that came to the FDA, more than 50% were reported by consumers.
WhatÂ’s your experience been with new medications? Have you had any bad experiences? How did you handle them?
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