7 Bizarre Drug Side Effects

Commonly prescribed drugs can cause very strange side effects. (Image credit: Shutterstock)

Prescription drugs are a mixed blessing. Millions of people rely on them to alleviate life-threatening or disruptive conditions. However, the chemical combinations within the drugs can cause bizarre and sometimes damaging side effects. Below are some of the strangest examples:  

Vanishing fingerprints                   

A few years back, U.S. immigration authorities held a Singapore man for hours after finding out he had no fingerprints. Turns out, according to CNN, he was taking a chemotherapy drug called capecitabine (Xeloda). Fingerprints reportedly disappear as the skin peels in reaction to the drug.


In the movies, amnesia (loss of memory) usually happens after a violent knock to the head. In medicine, however, short-term memory loss can also happen after taking certain medications. Some types of drugs blamed for this side effect include tranquilizers and sleeping pills.

Lost sense of smell

There have been some reports of patients completely losing the ability to smell (called anosmia) as a side effect of interferons, which are commonly used to treat hepatitis, leukemia and multiple sclerosis. One patient in Croatia stopped detecting scent just two weeks after taking the medication for the first time. Even 13 months after stopping the treatment, he still couldn't smell a thing.

Vegas, baby, Vegas

Using ropinirole (Requip) to treat restless legs syndrome or Parkinson's disease could lead to compulsive gambling and sex, according to its maker, GlaxoSmithKline. "Patients should inform their physician if they experience new or increased gambling urges, increased sexual urges or other intense urges while taking Requip," the drugmaker's product information states.

Midnight munchies

The sleeping pill zolpidem (Ambien) pops up in association with strange nocturnal side effects, including sleep-eating, sleep-cooking — even driving while asleep. Doctors are still searching for the cause, spurred by patients who worry about safety. "These people are hell-bent to eat," said Dr. Mark Mahowald, director of the Minnesota Regional Sleep Disorders Center, in a 2006 New York Times piece.


Mefloquine is an agent that fights malaria, but one that comes with a steep price. Patients have complained of hallucinations and even suicide attempts while taking the drug. In 2009, CBS News reported that Lariam — a  drug containing mefloquine — generated more than 3,000 reports of patients with psychiatric problems.

Blue urine

Blue is a rare color in nature, which makes it startling when it appears in toilet wastewater. Several drugs can cause blue urine, including the antidepressant amitriptyline, the painkiller indomethacin (Indocin) and the anesthetic propofol (Diprivan). The blue color comes from artificial colors in these drugs.

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Elizabeth Howell
Live Science Contributor
Elizabeth Howell is a regular contributor to Live Science and Space.com, along with several other science publications. She is one of a handful of Canadian reporters who specializes in space reporting. Elizabeth has a Bachelor of Journalism, Science Concentration at Carleton University (Canada) and an M.Sc. Space Studies (distance) at the University of North Dakota. Elizabeth became a full-time freelancer after earning her M.Sc. in 2012. She reported on three space shuttle launches in person and once spent two weeks in an isolated Utah facility pretending to be a Martian.