To keep people from using a common decongestant, pseudo-ephedrine, to make the illegal drug methamphetamine, federal law now requires that cold remedies such as Sudafed and Contac be moved from shelves to behind the counter. You have to show identification to buy them, and sign a logbook. Is it worth the hassle or should you try other options?

All decongestants reduce mucus production by constricting blood vessels in the nose. But some are safer or more effective than others.

Try nasal products first. Drops and sprays, such as Neo-Synephrine and Afrin 12-Hour, work faster than oral decongestants and are less likely to cause substantial side effects or drug interactions. But if used for more than about three days, they can cause rebound congestion, or renewed stuffiness that’s worse than the original problem. Switch to oral decongestants if the congestion lasts longer than a few days.

Opt for pseudoephedrine. To keep familiar brand names on the shelves, some manufacturers have substituted the decongestant phenylephrine for pseudoephedrine in their products. But a recent review of the evidence, published in the Journal of Allergy and Clinical Immunology, concluded that oral phenylephrine is unlikely to work. Our consultants say pseudoephedrine is clearly the better choice for most people who need an oral decongestant. Check with your doctor before taking either ingredient if you have hypertension, heart disease, diabetes, hyperthyoidism, or anxiety, or take other drugs.

A runny nose caused by a cold is best treated by an older antihistamine, such as chlorpheniramine (Chlor-Trimeton) or diphenhydramine (Benadryl Allergy). But those drugs can cause drowsiness, so they’re useful mainly when you don’t need to be alert. The newer, nondrowsy versions, such as loratadine (Claritin), won’t relieve a cold-related runny nose, although all antihistamines can stem the drip from an allergy.

Whenever possible, try non­drug steps first for treating congestion caused by a cold:

See your physician if symptoms last longer than two weeks or you have thick, colored mucus or more than a slight fever.