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The leg twitches are gone, but now I'm jonesing for the one-arm bandit

By Diane Mapes

We've all grown used to those rapid-fire disclaimers at the end of today's pharmaceutical commercials, where the announcer breathlessly rattles off all the potential side effects from taking the drug. Everything from death to dry skin to diarrhea.

Well, the commercials for restless leg syndrome (RLS) pills have brought something completely new to the table. 

Gambling? Sexual urges?

What's that about? 

It's about our old friend dopamine, explains Dr. Erika D. Driver-Dunckley, author of a recent study on gambling and increased sexual desire in patients taking the RLS medications Mirapex and Requip.

You know dopamine, that stuff in your brain that encourages you to drink and smoke and shop until you—and your credit score—drop.

"The medications in those commercials are for dopamine agonist drugs, which are drugs that go to your brain and stimulate dopamine receptors," says Driver-Dunckley, assistant professor of neurology at the Mayo Clinic in Scottsdale, Ariz. "It just so happens that dopamine receptors are in the part of your brain that controls movement—which is why the drugs are made to help with RLS and Parkinson's disease. But they're also found in the part of the brain that has to do with your reward/pleasure system."

Unfortunately, researchers haven't been able to make a drug that's specific enough to affect just the dopamine receptors that have to do with movement. "Getting a drug to work in one part of the brain and not another is very hard," she says. As a result, a small number of people—about 1 percent, studies show—who use dopamine agonist drugs may suddenly be overwhelmed with urges to gamble or have sex.

Or comb their hair.

"It's predominantly been gambling and sex that are reported," she says. "But we've also heard from patients about everything from impulsive shopping to eating to hair combing to gardening to playing solitaire on the computer for hours."

In a 2008 study of 300 patients taking dopamine agonist drugs for either Parkinson's or RLS, one person EVEN reported an urge for "wanton traveling." 

Yes, that's correct. Their restless leg medication actually gave them restless legs.

But dopaminergic side effects aren't all fun and (crap) games, if they're happening to you.
Driver-Dunckley says she's talked to people who've suddenly developed huge Internet porn habits or squandered their entire retirement savings at casinos. A 74-year-old Parkinson's patient developed "zoophilia as a possible complication of dopaminergic therapy," according to a 2002 study in The Annals of Pharmacotherapy. Apparently, shortly after having his meds increased, the poor guy tried to have sex with the family dog.  A few times.

"It's horrible and scary when something like that happens," says Driver-Dunckley. "But I prescribe these drugs to lots of people every day. "

In almost every case side effects are a result of improper dosage, she explains. "Most of the patients who experienced these problems were taking higher dosages of the drug than were prescribed."

Changing the dose ends the desire, she says.

As for those of you who might be wondering if an RLS prescription might be just the ticket to improve your luck at cards or love or both, forget about it.

"Most of the time, these people didn't get lucky," says Driver-Dunckley. "It didn't make them a good gambler, just one who was unable to control their gambling urge."