Drugstore Indecision

Cold Sores

The Drug: Abreva

Why it's No. 1: Got that telltale tingle that signals that a cold sore the size of Donald Trump's ego is about to sprout on your lip? Abreva can bring it to a screeching halt. "It prevents the virus from infecting healthy cells, which stops the cold sore from erupting," says W. Steven Pray, Ph.D., D.P.H., professor of nonprescription drugs at Southwestern Oklahoma State University College of Pharmacy in Weatherford. The drug works by creating a barrier around skin cells that makes it more difficult for the cold sore virus to penetrate them. "No other nonprescription product can do that."

Generic: None. The soonest one could be available is 2014.

Fine print: Dash to a drugstore the minute you feel a cold sore coming on. "Once the sore develops, using Abreva isn't as effective, because the time for prevention has passed," says Elaine D. Mackowiak, Ph.D., R.Ph., professor of pharmacy practice at Temple University School of Pharmacy in Philadelphia. "At that point, you can use any topical cold sore treatment, such as Anbesol, Orajel, or Zilactin, to reduce discomfort."

See a doc if the sore hasn't healed after 10 days.

Constipation

The Drugs: Metamucil and Dulcolax

Why they're No. 1: When it comes to making regular deposits, the magic word is fiber. Metamucil is druggists' remedy of choice because it contains psyllium, a natural plant fiber that softens and bulks up your stools. (It may sound counterintuitive, but it's easier for your digestive system to transport soft, bulky stools than hard, small ones, which can stick to the walls of the colon and block the way.) Plus, "Metamucil is effective and safe to take every day," Pray says, which means you can use it to help prevent system backups.

The one snag is that the medication can take time to work--usually 12 to 72 hours--which is why pharmacists also recommend Dulcolax, a stimulant laxative that does the trick in less than 12 hours. "Dulcolax stimulates the nerves that propel food through your body's gastrointestinal tract," says Paul L. Doering, M.S., distinguished service professor of pharmacy practice at the University of Florida College of Pharmacy in Gainesville. "It gets things moving, but it's gentler than other stimulants, so it won't leave you doubled over the toilet in pain."

Generic: Psyllium for Metamucil and bisacodyl for Dulcolax

Fine print: If you use Metamucil powder, gulp it down as soon as you mix it with water, says Janet Engle, Pharm.D., clinical professor of pharmacy practice at the University of Illinois at Chicago College of Pharmacy.Otherwise you'll end up with a thick, rubbery (and wholly undrinkable) blob in your glass. Doering also warns against taking a stimulant laxative like Dulcolax for more than a few days in a row. Use it longer than that, he says, "and your bowels may start to rely on the medication to do their job."

See a doc if you're backed up for more than week.

Diarrhea

The Drug: Imodium A-D

Why it's No. 1: When a case of the runs tethers you to the toilet, Imodium A-D can help slow the flow. "It reduces the frequency of bowel contractions, so everything moves at a calmer pace," Pray says. "It also gives your stools more firmness." All of which makes for a happy colon. Bismuth subsalicylate, the active ingredient in Pepto-Bismol, another popular option, isn't as strong, which means the drug doesn't slow things down as efficiently, according to Kim Broedel-Zaugg, Ph.D., professor of pharmacy practice at Ohio Northern University College of Pharmacy. "But with Imodium, you're definitely going to find relief." So being more than five feet away from the nearest bathroom is no longer cause for panic.

Generic: Loperamide HCl

Fine print: Try to pinpoint the cause of your gastrointestinal distress before you pop a pill, Engle recommends. In some cases, you may actually be better off just riding it out. "If you've got a case of food poisoning, for example, taking an antidiarrheal drug will prevent toxins from being flushed from your body, prolonging the entire episode," she says.

See a doc if your diarrhea hasn't gone away after 48 hours or you develop a fever.

Hay Fever and Allergies

The drug: Claritin

Why it's No. 1: "Allergens trigger your immune system to release histamine (an inflammatory compound), which causes runny nose, itching, sneezing, and congestion," Mackowiak says. Claritin sets up a roadblock against that histamine release to prevent allergy symptoms from occurring. Plus, it's much less likely than other OTC antihistamines to cause drowsiness, a common side effect. In fact, a 2005 study by researchers at the Washington Neuro-psychology Research Group in Washington, D.C., found that seasonal allergy sufferers who took Claritin were as alert and focused as those participants who didn't have allergies.

Generic: Loratadine

Fine print: The drug works best if you take it before you're exposed to the allergy trigger, Mackowiak says. So swallow a Claritin 30 to 60 minutes before you head out to mow the lawn or visit your boyfriend's cat-lady aunt.

See a doc if your symptoms don't let up or they become more severe while you're taking the medication.

NEXT: Heartburn and Headaches