This evening, at least one out of 10 American adults will be tossing and turning as uncontrollable and overwhelming tugging sensations surge through their legs. This is Restless Leg Syndrome (RLS), a neurological disorder also known as Willis-Ekbom Disease. And because the syndrome is able to be managed, not cured, sufferers often look to such OTC sleep aids to stay down for the night. An unfortunate side effect of such drugs is that they can exacerbate the already-uncomfortable symptoms of RLS.
RLS happens mostly at at night and is marked by unpleasant feelings in the legs and the overwhelming urge to move them. Often, a few seconds of movement relieves the discomfort, but the sensations return soon after and sufferers feel compelled to move again. The disorder makes it difficult to sleep. And when sufferers do manage to conk out the vicious tingle-shake-stop cycle is likely to cause "micro arousals,” which can also add to chronic sleep issues and fatigue.
What causes it? Well, we’re not really sure. The problem has to do with dopamine levels in the brain and the nerves that control sensation and movement in the limbs, says Dr. Russell B. Skinner, owner and practitioner at Family Health and Wellness in Plano, Texas, but it’s still rather vague.
Researchers have, however, noted changes in activity when scanning the brains of those with RLS, including changes in the hypothalamus, which affects sleep-wake cycles and thermoregulation, and also in the cerebellum, which plays a role in motor control and certain cognitive functions.
“We know something is happening in the brain, but we don’t know what specifically drives those things,” says Dr. Brian B. Koo, assistant professor of neurology and director of the Restless Legs Quality Care Center at Yale University.
While there is no cure for RLS, it can be managed. Medications exist (they’re the same used to treat the tremors and other results of Parkinson’s disease) but RLS’s symptoms are often lessened by quitting smoking, consuming less caffeine and other such lifestyle changes, says Koo. Iron supplements might also help.
To combat the restless nights, many suffers seek out OTC sleep aids. But, as Koo says, anything marked “PM” can make it more difficult for RLS patients to nod off.
“Many of these medicines include diphenhydramine, an antihistamine, that worsen RLS,” says Koo. Dipehendhydramine blocks dopamine receptors in the brain and amplify the telltale RLS sensations.
“It’s this ‘canceling’ of dopamine that makes the symptoms worse,” Skinner says.
Both Tylenol PM and Benadryl, both commonly used to conjure sleep, contain diphenhydramine.
So, keep an eye out. If you happen to suffer allergies and RLS, Skinner suggests taking non-drowsy antihistamines such as Claritin, Zyrtec of Allegra, as they’re unlikely to worsen symptoms. Nasal steroid sprays and leukotriene receptor blockers are fine solutions, too, and don't tack on to the tingle.