Chances are you have some cold and allergy medication stashed away in your medicine cabinet somewhere. Chances also are that, if you flip the box over, you'll see phenylephrine as one of the active ingredients listed. As a decongestant, its job is to help relieve the nasal congestion that often accompanies a cold or allergies.

But whether this popular decongestant actually helps clear a stuffy nose has been questioned by doctors for quite some time.

"In the medical community, we've long known that oral phenylephrine doesn't work as a nasal decongestant," says Dr. Joshua Septimus, a primary-care physician at Houston Methodist. "We've known this since it became the replacement for pseudoephedrine back in the early 2000s."

Now, the FDA is weighing in. An independent advisory committee to the agency unanimously agreed this week that oral phenylephrine is ineffective as a nasal decongestant. Whether the FDA decides to update the drug's current classification as Generally Recognized As Safe (GRAS) and pull it from shelves remains to be determined.

In the meantime, you've likely got some questions about those cold and allergy medications still occupying space on pharmacy shelves or your home medicine cabinet.

Why was phenylephrine ever used in the first place?

In 2006, the FDA issued a requirement that pseudoephedrine — the oral decongestant of choice — be moved "behind the counter." The change was borne of the medication's misuse for the production of methamphetamine, an illegal drug.

Behind the counter doesn't mean a prescription is needed to buy a product containing pseudoephedrine, but it does mean you can't just grab it off the shelf yourself. You have to request it from the pharmacist.

As drug companies searched for ways to make cold and allergy medications easily accessible again, they turned to phenylephrine — which works similarly to pseudoephedrine but is less likely to be used illicitly.

"The problem is the FDA has found that oral phenylephrine is ineffective based on clinical data," says Dr. Septimus. "In fact, studies show that oral formulations are quickly digested and metabolized, with very small amounts of the drug making it into the bloodstream and even less making it to the nasal cavity."

Is it still safe to take cold or allergy medications containing phenylephrine?

Given that oral phenylephrine doesn't actually provide a benefit, should you avoid taking a multi-symptom cold or allergy medication containing it?

"The overall safety of phenylephrine isn't being questioned," says Dr. Septimus. "But we never want people to be taking medications they don't need."

Plus, phenylephrine can cause unwanted effects, including headaches, trouble sleeping and even a fast or irregular heartbeat. Medications containing the ingredient also carry warnings for people with high blood pressure, heart disease, diabetes, liver disease and more.

"You should always consult your doctor before taking an over-the-counter medication," says Dr. Septimus. "Underlying health conditions, as well as other drugs you're already taking, can influence whether an over-the-counter medication is safe for you or not."

What are the alternatives to phenylephrine?

If you find yourself with an unbearably stuffy nose, there are several over-the-counter options to turn to instead of ones containing phenylephrine.

First, you'll likely want to skip over most of the multi-symptom cold and allergy medications — as phenylephrine is almost always used as the decongestant included in them.

Here are five ways to relieve congestion instead:

• Nasal decongestant sprays – Unlike oral preparations, nasal spray phenylephrine is considered to be effective. So is oxymetazoline, an alternative decongestant commonly used in these sprays. But be sure to take these medications as directed to avoid what's called rebound congestion.
• Oral pseudoephedrine – Yes, you'll have to ask the pharmacist for it. And no, it might not be the right option for everyone. But this decongestant's effectiveness has never been in question.
• Antihistamines – These medications can take a few days to work, but they relieve congestion in a different way, by reducing nasal inflammation. They can be taken longer than decongestant sprays and they're not behind the counter.
• Nasal steroid sprays – These sprays relieve congestion in a way similar to oral antihistamines, but work a little faster — usually within a day. They can also be taken longer than decongestant sprays and they, too, are not behind the counter.
• Saline rinses – Whether congestion is caused by a cold or allergies, frequent saline rinses can help clear mucus, pollen and any other debris clogging the nasal cavity.
  
  

(Related: How to Get Rid of Congestion)