Antihistamines like Benadryl (diphenhydramine) often make people drowsy. No surprise.
Antibiotics frequently cause diarrhea and digestive upset because they wipe out helpful intestinal bacteria along with the infection.
Doctors often warn patients about such predictable side effects. But other side effects may slip past the experts because they are unexpected.
Antidepressants such Prozac, Paxil or Zoloft belong in a class called SSRIs (selective serotonin reuptake inhibitors). Hardly anyone is surprised if such a medication causes anxiety or insomnia. Psychological side effects seem consistent with a drug that affects the brain.
New research suggests, though, that these SSRI antidepressants also increase the risk for bleeding ulcers (Archives of General Psychiatry, July, 2008). These drugs have been on the market for two decades, but only in the last several years have researchers recognized a link between upper GI bleeding and these antidepressants.
Part of the delay is because our medical system is fragmented. Psychiatrists prescribe antidepressants but they rarely see people with serious digestive distress. Gastroenterologists see people with bad bellyaches, but may not associate a hemorrhage in the stomach with an antidepressant.
When the right hand doesn’t know what the left hand is doing, patients can suffer. Uncoordinated care can lead to complications from many medications.
Take antibiotics, for example. Doctors often prescribe drugs like Cipro or Levaquin for sinus or urinary tract infections. One side effect of these medications that may come as a surprise is tendon rupture.
One reader shared this story:
“I took Levaquin to treat a lung infection. After five days I noticed tightness in my left Achilles’ tendon that hampered my ability to walk. Three days later my left ankle was so swollen I could hardly hobble. An MRI showed a completely severed Achilles’ tendon. I needed surgery and then spent six weeks in a wheelchair.”
Who would guess that a snapped Achilles’ tendon could be the consequence of treating bronchitis with an antibiotic?
Hundreds of drugs have unexpected side effects. The popular class of reflux medications that includes Aciphex, Nexium, Prilosec and Protonix has been linked to hip fractures (JAMA, Dec. 27, 2006). Because these heartburn drugs are so effective at suppressing acid, they may interfere with the absorption of certain nutrients such as calcium. Theoretically this could contribute to weakened bones.
The doctors who deal with patients’ heartburn symptoms usually aren’t consulted if a patient breaks a hip. The orthopedic surgeons who fix broken hips may not link such fractures to medication taken for reflux.
It can take a long time for the FDA to warn the public about unexpected drug side effects, such as tendon rupture with Cipro-type antibiotics. Even though epilepsy medicines have been on the market for many decades, it is only now that the FDA is considering a black box warning about the potential for these drugs to cause suicidal behavior.
To help the FDA discover unanticipated reactions to prescription medications, such side effects should be reported to MedWatch (www.fda.gov/medwatch).
