Beware Belated Drug Side Effects

Car buyers used to be advised that it would be prudent to wait at least a year after a new model was introduced before making a purchase. That way, the manufacturer had a chance to detect and correct unexpected flaws.
The same precaution applies to new computer programs. Many businesses wait several months, if not longer, for bugs to be worked out of new software before they switch over.
We wish more doctors exercised the same level of prudence. The question is how long should we wait to discover unanticipated adverse drug effects?
Some experts recommend waiting at least a year. Others say that’s not long enough. Despite the fact that the FDA proclaims all drugs it approves are safe and effective, there are many examples of serious complications discovered well after a drug comes on the market.
The best known is Vioxx. This pain reliever was introduced in 1999 as a breakthrough for arthritis. It was supposed to be safer for the stomach than older NSAIDs like ibuprofen. It wasn’t until 2004 that the company pulled Vioxx off the market because it increased the risk of heart attacks and strokes. Thousands of patients may have died during that time.
It took even longer to discover complications from hormone replacement therapy (HRT). Drugs like Premarin (first marketed in 1942) and Prempro (introduced in 1995) were taken by millions of menopausal women. It wasn’t until the Women’s Health Initiative in 2002 that the risks of heart attacks, strokes and cancer associated with HRT were widely acknowledged.
The antidepressant Prozac hit the market in 1987. It quickly became one of the most popular drugs in the pharmacy. It wasn’t until 2004 that the FDA required manufacturers of antidepressants like Prozac to warn about suicidal thoughts and actions in children and adolescents taking these medications. Late last year the agency was advised to extend that warning to young adults.
More recently we have learned that people who take powerful acid-suppressing drugs (including Aciphex, Nexium, Prevacid, Prilosec and Protonix) for more than a year may have an increased risk of hip fractures (Journal of the American Medical Association Dec. 27, 2006). A possible explanation for this effect may be too little calcium. A low-acid environment in the stomach could make it more difficult to absorb this crucial nutrient.
Because this is such a new discovery, the FDA has not included any warning about bone problems in the official label information. It could be a long time before doctors or patients will be cautioned about this potential effect since the FDA often moves slowly when it comes to labeling changes.
What we’ve learned over the last few decades is that it can take years before serious side effects surface. The FDA approves most medicines on the basis of relatively short-term studies that last several weeks to several months. As a result, we often don’t know the long-term risks of a new medicine.
To be safer, monitor how your body reacts to a new medication. If you suspect that something is not right, talk it over with your doctor. And when you see an ad on TV for a new prescription drug, don’t beg your doctor to prescribe it. It may have unexpected hazards.