The bible of drug information is the Physicians’ Desk Reference (PDR). It contains the prescribing guidelines for medications provided by drug companies and approved by the Food and Drug Administration.
All of the data on drugs found in pharmacy leaflets, online resources and consumer publications comes from this source. Doctors rely on the facts they find in the official label to weigh benefits and risks of medications and inform patients about the likelihood of experiencing certain side effects.
What if this document were flawed? The FDA relies on the manufacturer to supply data about side effect frequency during the approval process. Research suggests that the drug label sometimes underestimates how often bad reactions occur.
More than 100 million prescriptions are filled each year for blood pressure medicines called ACE inhibitors. These are drugs like benazepril, enalapril, fosinopril, lisinopril, quinapril and ramipril. These medicines are perceived to be highly effective and extremely safe.
ACE inhibitors have a noteworthy side effect, however. These drugs can cause an unrelenting cough. Doctors who count on the FDA’s labeling may downplay this risk, as this reader reports: “My doctor prescribed lisinopril to treat high blood pressure. I was told there was a ‘slight chance of a mild cough’ with this medication but that I should take it because it worked so well.
“I developed a cough that got so bad I could hardly choke out a sentence. Talking was nearly impossible and so was sleeping. I was coughing so violently that I frequently found myself in the bathroom hunched over the toilet gagging or dry heaving. I coughed so hard I ruptured a blood vessel in my eye, and I pulled muscles in my back and abdomen.
“The first doctor I saw for this cough diagnosed bronchitis and gave me antibiotics and an inhaler. It didn’t help. I was then diagnosed with asthma and prescribed a nebulizer.
“An allergist ruled out allergies or asthma and said the cough could be due to acid reflux or an infection. He gave me Prevacid and another antibiotic.
“A few weeks ago I saw another doctor who said he thought lisinopril was the cause of my cough. This drug has basically ruined the last half-year of my life and cost me hundreds if not thousands of dollars. Doctors need to do their research and warn their patients before prescribing these drugs.”
Research comparing the reported incidence of cough in the PDR/drug label with that in clinical trials found that the actual rate of cough for ACE inhibitors was many times higher than the rate quoted in the PDR (American Journal of Medicine, Nov. 2010). As the authors note, side effect information in the drug label can be deceptive.
The labeling information for other drugs also may be inaccurate. Antidepressants, for example, often cause sexual side effects. These are far more common in real life than in the prescribing information. The same may be true for muscle pain caused by statin-type cholesterol-lowering drugs.
Incomplete data may give both patients and physicians a false sense of security. This can result in needless doctor visits and unnecessary medications, as our reader discovered the hard way.
