Look Alike, Sound Alike Drugs and Women's Health

Data collected from a number of patient safety reporting programs indicate that between 2% and 35% of prescription errors are linked to look alike, sound alike drug name similarities.

Pharmacists are wary of products that have look-alike and sound-alike (LASA) names because they increase the likelihood of prescription error. Data collected from a number of patient safety reporting programs indicate that between 2% and 35% of prescription errors are linked to LASA drug name similarities. Sometimes, when pharmacists are technicians look at a prescription and think it is one drug, examining the directions for use helps them realize that the prescriber actually wants a LASA medication.

Researchers from the FDA found evidence that prescribers use the signa “use as directed” on 1% to 5% of prescriptions rather than explicit directions, according to the published study in the journal Therapeutic Innovation & Regulatory Science. They used a national outpatient physician survey’s data, and analyzed the relationship between the use of “as directed” and products most likely to be labeled in this way.

The table below lists products most often labeled “as directed.” Several categories are of concern in women’s health as they are drugs used exclusively by women.

Table. Products Most Often Labeled “As Directed”

  • Inhalers
  • Oral contraceptives
  • One-time treatments, such as those for lice or scabies
  • Prepackaged items with specific directions for use on the package
  • Migraine medications
  • Erectile dysfunction medications
  • Bowel evacuation/colonoscopy preparations
  • Topical medications
  • Medications with regimens that may change frequently (eg, warfarin, insulin)
  • Otic products
  • Transdermal products
  • Products administered vaginally
  • Products administered rectally
  • Products that may be titrated upon initiation

These researchers determined that prescribers are likely to write “take as directed” if oral contraceptives or vaginally administered products are ordered or if prescribers expect to titrate or make changes to a prescription’s directions often. The researchers didn’t identify many injectable drugs that tended to be labeled “use as directed,” but noted that fertility injections were very likely to be labeled in this manner.

Pharmacists will note as they examine the list of products that many patients would benefit from having better directions on the product’s label. The researchers indicate that drug manufacturers and the FDA should consider the likelihood that a product will be prescribed with “as directed” labeling for patients when they consider LASAs. Pharmacists who dispense these products should increase counseling to patients to make sure that they understand specifically and precisely what “as directed” means.


Rider BB, Mehta H, Merchant L. Special considerations for proprietary name review: Focus on products that may be prescribed "as directed". Ther Innov Regul Sci. 2018 Jan 1:2168479018782669. doi: 10.1177/2168479018782669. [Epub ahead of print]