Nicotine patches can be harmful to children.

So reports a team of researchers who spent two years studying accidental nicotine poisoning cases in children under 16 years of age. The patches, which are used to help adults quit smoking, are available without a prescription. Estimates are that 16 million Americans try the patches annually to stop smoking.

Nicotine is slowly released from the patches into the skin to lessen the withdrawal symptoms in people trying to quit cigarettes. But even used patches can contain as much nicotine as that found in four to seven cigarettes, more than enough to make a child sick, according to a team of researchers led by Harvard University scientists.

Thirty-six children were exposed to nicotine patches from November 1992 to October 1994, according to data collected from 34 poison control centers including the National Capitol Poison Center in Washington.

In 21 cases, children discovered a discarded used patch in the garbage or opened a package of new patches. In four cases, children were exposed to nicotine patches that fell off an adult. Other patches became attached to a child's skin while the child was sleeping in the same bed as an adult who had been wearing the patch. One patch fell off in the wash and adhered to a child's pajamas. In another instance, a child mistook a patch for a bandage and one 5-week-old baby sucked on a patch attached to an adult's arm.

About 40 percent of the children exposed to nicotine patches developed symptoms including nausea, vomiting, diarrhea and abdominal pain, as well as weakness, dizziness and rashes. Ten children were treated in hospital emergency rooms, two required an overnight stay at the hospital, but all recovered fully.

The easy availability of the patches "may mislead parents into thinking that the products have little potential for toxicity," the authors note in the May issue of the Pediatrics electronic pages, an online scientific journal published by the American Academy of Pediatrics. "Parents should safely store transdermal nicotine patches as they would any other medication in locked cabinets out of reach of toddlers."

Adults also need to be "vigilant that the patch does not fall off during sleep or during a shower or that their toddler does not dislodge it from their skin without their knowledge." And all used patches should be properly disposed of to ensure that children "cannot gain access to it."