LOOK-ALIKE DRUGS
These tablets are almost twins
Both indapamide 2.5 mg (ANI Pharmaceuticals) and spironolactone 25 mg (Amneal Pharmaceuticals) are round white tablets that are virtually identical in color, size, and shape (see photos below). In addition, indapamide has an imprint code of ANI 511 and spironolactone has a very similar imprint code, AN 511. As shown in the photos, these qualities make them extremely difficult to tell apart visually, setting the stage for a medication error. In community pharmacies, both medication bottles might be on the work counter at the same time; for example, a patient might have prescriptions for both indapamide, a thiazide-like diuretic, and spironolactone, which helps manage potassium loss from indapamide. Given that the tablets look identical, pharmacy staff could easily return unused tablets from a counting tray to the wrong bottle or robotic dispensing container, and then later mistakenly dispense the wrong medication to another patient. Routine safety measures such as reading container labels and scanning bar codes are unlikely to prevent this type of error.
Mixing up these two drugs could be harmful. If spironolactone tablets were placed into an indapamide container, spironolactone might be dispensed to patients who already take spironolactone, which could lead to hyperkalemia. Or, if indapamide is mistakenly dispensed instead of spironolactone, a patient could experience hypokalemia from taking two tablets of indapamide. In addition, a patient who uses online tablet/capsule identification resources could easily misidentify these tablets.
Pharmacists should ensure that both brands are not stocked in the pharmacy. There are alternative manufacturers, especially for spironolactone 25 mg.
Technically, these products may meet FDA requirements that tablets be clearly marked or imprinted with a code that, in conjunction with the product's size, shape, and color, permits the unique identification of the drug product. However, to prevent confusion, the best solution would be for one of the companies to voluntarily change the tablet code and tablet appearance.
TACROLIMUS
Using generic name invites confusion
Tacrolimus is an immunosuppressant indicated to prevent organ rejection. A prescription for oral tacrolimus extended-release (Astagraf XL) 3 mg daily was intended to be dispensed from a hospital outpatient pharmacy using three 1 mg extended-release capsules for each dose. However, the pharmacist mistakenly selected tacrolimus 1 mg immediate-release (Prograf) capsules instead of Astagraf XL. All tacrolimus products were in the same drop-down menu because the hospital's computer system displayed all strengths of an active ingredient in a single list. Also, immediate-release and extended-release tacrolimus products are available in similar 0.5 mg, 1 mg, and 5 mg strengths, which may increase the potential for confusion between the two dosage forms. The error was discovered when the patient noticed a difference in how the capsules looked compared with prior refills and reported it to the pharmacy.
To prevent this type of error, the Institute for Safe Medication Practices (ISMP) recommends displaying the brand name of tacrolimus extended-release formulations (for example, Astagraf XL or Envarsus XR) on medication ordering and verification screens to help differentiate them from immediate-release tacrolimus such as Prograf and generic formulations. When prescribing immediate-release tacrolimus, providers should use only the brand or generic name without modifiers such as "IR" for immediate-release. Using generic names with abbreviated modifiers can introduce confusion because the meaning of modifiers such as IR and extended release (ER or XL) can vary depending on the manufacturer.
ISMP published a review of multifactorial causes of tacrolimus medication errors, including confusion with the various strengths and formulations, look-alike names, and preparation errors. Read it at http://www.ismp.org/node/182.