Two types of customers come in to the pharmacy for OTC medications: those who know exactly what they want and those who want relief but are unsure what will help. While a pharmacist’s intervention often comforts the latter, it may be just as essential for the former. Many individuals accustomed to treating themselves remain unaware of potential medication interactions and side effects, sometimes with serious repercussions.

A patient with a cold, for instance, may have a preferred decongestant. If patients come to the counter to request one containing pseudoephedrine, you may want to check their prescription history or ask about hypertension. Pseudoephedrine can cause a spike in blood pressure, so a short-acting version might be better than the extended-release formulation. Another category of decongestant might be better still. You should also mention other potential side effects, including insomnia and urinary retention, particularly for older men who have benign prostatic hyperplasia.

Other patients may select a decongestant with phenylephrine off the shelf. In the last decade, many manufacturers have substituted phenylephrine to create decongestant formulations that are not subject to FDA regulations requiring pharmacists keep drugs with pseudoephedrine behind the counter. These often go by variations on the name of the original pseudoephedrine-containing drug.

Similar names do not mean similar efficacy, however. A study in the New England Journal of Medicine found that products with phenylephrine as the active ingredient performed no better than placebo in alleviating congestion. In addition, patients taking the products with phenylephrine experienced nearly three times the rate of adverse nervous-system or gastrointestinal events and one patient reported serious chest and lower jaw pain, which resolved with discontinuation of the drug. In some patients, phenylephrine can also elevate blood pressure.

“Oral phenylephrine should not be recommended for allergic rhinitis. In addition, little evidence supports its use in alleviating common cold symptoms, so, until we have data supporting its effectiveness, I would not recommend it for any nasal congestion,” said David J. Amrol, MD, in a summary of the practice-changing recommendations in NEJM.

Alternatively, customers with congestion could find the quickest relief with the fewest likely side effects by using a fast-acting nasal spray containing oxymetazoline. Even these deserve a word of warning, however, as use for more than 3 days frequently leads to inflammation of the nasal tissues and rebound congestion.

Customers who have congestion as a result of allergies may also need your advice. While many patients with chronic allergies have taken the same medications for years, the risks may outweigh the benefits as time goes on. Older patients with insomnia may welcome the sleep-inducing qualities of short-acting antihistamines containing diphenhydramine and chlorpheniramine, but those who get up during the night for a bathroom run may find that the drugs impair coordination and increase the risk of potentially catastrophic falls. Customers who regularly take sedatives to help sleep will also want to avoid these drugs, as will those who need to drive after taking the medications.

First-generation antihistamines may also increase urinary retention and exacerbate narrow-angle glaucoma. For elderly patients, second-generation antihistamines, such as those containing loratadine, cetirizine, or fexofenadine, minimize these risks. Patients with kidney or liver disease should discuss the use of any antihistamine with their physician.

« Click here to return to OTC Update.