Patch it up, doc

The next time you go to the doctor to get patched up, you might walk away with just that – a patch. A growing number of drugs are now available via transdermal patch, a sticker that releases medication directly through the skin. “We do more and more,” says John Amini, a pharmacist at Medicine Man Pharmacy in Liberty Lake. “It’s the ease of administration. It’s easier than taking a pill.”

The market for patches is fast-growing. The Food and Drug Administration just recently approved the first attention-deficit-hyperactivity disorder skin patch. And, earlier this year, the first antidepression patch won approval.

In the United States, transdermal patches earned revenues of $2.97 billion in 2005, according to market-research group Frost & Sullivan. That number is expected to grow to nearly $4.5 billion in the next half-dozen years, the group predicts.

The boom is fueled largely by a growth in drugs to treat central nervous system disorders (like Parkinson’s) that are now, or soon will be, available via patch, the market research says.

Reason No. 1 for choosing a patch over pills is an obvious one: It’s easier to slap on a patch once, or even a few times, a week than to remember to pop pills several times a day.

But there are plenty of other reasons for the patch’s rising visibility, says Shelley Chambers-Fox, a clinical associate professor in Washington State University’s Department of Pharmaceutical Sciences. Chambers-Fox teaches a course about ways to administer medications, and patches are a hot topic.

Some patients, especially the elderly, simply can’t swallow pills, making them good candidates for drugs via patch, she says. In other cases, patients can’t tolerate side effects of oral medications, but those effects are minimized when the drug is delivered through the skin.

“The great thing about this technology is that it does release in a very sustained fashion,” Chambers-Fox says. “You don’t get those peaks that can cause you some side effects. You also don’t get the valleys. It gives you much more even levels.”

In some cases, though, the increased amount of medication in the patch can actually up the odds of suffering side effects. Such is the case with the Ortho Evra birth-control patch, which made news last year when some women using it suffered serious blood clots.

The drug now comes with a new warning on the label, telling women that they are being exposed to a much higher dose of estrogen than those taking a comparable pill.

Patches first came into use in the late 1970s and early ‘80s. The first drug administered by patch was nitroglycerine, used to ease chest pains in cardiac patients.

The skin serves as our natural barrier to the outside world. But drug developers have found ways to get through that barrier to push certain medications through the skin and into the body.

Currently there are two basic designs for transdermal patches. Both types use a large quantity of medication per patch to ensure that enough of the drug seeps into the skin. The dose delivered is determined by the size of the patch. The more skin in contact with the patch, the higher the dose.

In one design, the drug is sandwiched between the patch and a thin membrane. The film helps control the amount of medication released from the patch throughout the day. Duragesic, a popular pain-control patch, uses such a membrane.

The other type of patch is created when the drug is mixed with a polymer to create a thick, plastic-like patch. This type of design relies on the skin to control how much medication flows into the body. This design is used in the Minitran nitroglycerine patch.

Scientists have been working on a new patch design for more than a decade, Chambers-Fox says. The new patch has a small electrical current embedded in it, to give an extra boost to medications that have trouble passing through the skin.

Whenever that enhanced patch becomes available, “they open up this technology to a huge number of drugs that just weren’t suitable before,” she says.

Nancy Parker, 63, of Spokane has worn a hormone-replacement patch for about a decade. She spent an equal amount of time taking estrogen by mouth but found she was suffering from reflux and heartburn.

Those side effects have gone away now that she’s using the patch, she says, and her terrible menopausal symptoms are also under control.

“My side effects are so bad, I’m not going to be without it,” Parker says. “I’m dedicated to my patch.”

Parker tried different brands of estrogen patches before finding Estradiol, the only one that would adhere well to her body. She says she occasionally gets a rash from the adhesive but has no other ill effects.

Spokane pediatrician Dr. Tim Seppa, who practices at the Riverfront Group Health clinic, says he hasn’t used many patches on his young patients in his 30 years in medicine. And he’s not particularly excited about the recently approved patch to treat attention-deficit-hyperactivity disorder.

“It doesn’t look like there’s any big advantage over using sustained-release pills,” Seppa says.

Plus, he worries that kids already prone to behavioral problems would be more likely to pick at the patch and try to remove it.

People who take medication by patch do need to watch out for a few things, Chambers-Fox says.

Because patches contain such a concentrated dose of medication, it’s important to dispose of them carefully. You wouldn’t want a child or a pet finding a used patch that still had some active medicine left in it.

Also, users must remember to remove the old patch before putting on a new one so they don’t get extra medication.

And the patch should be moved to different parts of the body to minimize skin irritation, Chambers-Fox says.

“The trunk, upper arms and back would be good,” she says. “You want to stay away from parts that move because you can actually wiggle them off.”