Ongoing mix-ups with two common drugs


Our organization, the Institute for Safe Medication Practices (ISMP), often receives medication error reports that result from confusion with drug names that look or sound alike. One look-alike and sound-alike pair that often results in confusion is hydrALAZINE and hydrOXYzine.

HydrALAZINE, also known by the brand name Apresoline, is used to treat high blood pressure. HydrOXYzine, also known by the brand names such as Vistaril and Atarax, is used to treat symptoms of an allergic reaction, such as itching or a rash, but it is also used to treat nausea and anxiety.

Recently, a medication error was reported to us involving a 21-year-old man who was taken to the emergency department complaining of a headache, numbness in his arms and legs, and difficulty breathing. The man told the hospital staff his symptoms started after he took a new prescription medication for anxiety and insomnia. The man showed them the bottle of medicine which was labeled hydrALAZINE 25 mg (take 1-3 tablets every 6 hours). The physician, who suspected an error likely occurred, called the pharmacy to question the prescription. The pharmacy confirmed the mix-up. The pharmacy had indeed received a printed prescription for hydrOXYzine but in error filled it with hydrALAZINE. The man was eventually discharged from the emergency department with a new prescription hydrOXYzine.

In another case, a woman reported a medication error with her dog. The veterinarian prescribed hydrOXYzine for the dog. The pet’s owner administered the medicine for two days before noticing the drug information sheet indicated the medicine was for blood pressure. The consumer called the pharmacist who confirmed a mix-up did occur. The dog was actually dispensed hydrALAZINE instead of the prescribed hydrOXYzine.

Over the last 10 years ISMP has written about dispensing errors between these two medications. However, despite warnings and multiple recommendations to healthcare practitioners, we continue to receive reports of mix-ups between these two drugs. Contributing factors leading to these frequent mix-ups are:

• The first 4 letters of their names are identical
• They are frequently stored next to one another on pharmacy shelves
• They are listed alongside one another on computer screens
• They have similar dosage strengths (10, 25, 50 and 100 mg)

If you receive a prescription for either hydrALAZINE or hydrOXYzine, it is important to be on the lookout for potential mix-ups between these two drugs. When picking up your prescription always be sure to confirm you have the correct medication before leaving the pharmacy. Additionally, request your physician to include the reason for the medicine on your prescription. Knowing the medication's purpose can help the pharmacist verify the prescriptions purpose with the proper drug.

Created on December 11, 2015

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