USP Quality Review

No. 48, Revised 8/95

COMPUTERS: ERRORS IN—ERRORS OUT

Close to 100 percent of all pharmacies in the United States use computerized systems to process prescriptions and patient profile information. Computers have improved consistency and made the rigorous processing of OBRA, DUR, state, federal, and third party requirements easier, faster, and more organized—as long as the data entered is correct. Reports received through the USP Medication Errors Reporting Program and the USP Board of Pharmacy Medication Errors Reporting Program show that computers have been the source of various kinds of medication errors. The inadvertent entry of an incorrect mnemonic, either for the product or for directions for use, and the improper choice from computer generated patient or product lists have been implicated frequently.

The following are examples of reported computer entry errors that were received through these programs:

Doxepin vs. Doxycycline
The pharmacist chose the incorrect drug because the same mnemonic, DOX100, was mistakenly used by the software programmer to designate two different drugs, doxepin and doxycycline. The elderly patient received three doses of doxepin, causing an increased hospital stay.

Ancef® vs. Anectine®
A pediatric patient was to receive the antibiotic Ancef (cefazolin sodium). Instead of utilizing the mnemonic ANCE 500 I, the pharmacist chose a similar mnemonic, ANEC 500 I, for Anectine (succinyl choline chloride). A large volume of Anectine, instead of Ancef, was consequently prepared and sent to the pediatric floor. An astute nurse discovered the mixup before the incorrect product was administered to the patient.

Calan® vs. Corgard®
A prescription was written for Calan 40 mg but Corgard 40 mg was selected from the computer list instead. It was dispensed to the patient twice before the error was discovered. This reinforces the need for verifying refills with the original prescription.

Teaspoonful vs. mL
By default, a certain software program prints teaspoonful for any syrup preparation when a numerical figure not followed by a specific measure, such as mL, is entered for the dose. A prescription for 1/2 mL albuterol syrup every 6 hours for a nine-week old infant was presented to the pharmacy, and the pharmacist entered "1/2" into the computer but did not enter the mL. Therefore, by default, the label printed 1/2 teaspoonful every 6 hours if needed for wheezing. The child was administered the overdose and consequently admitted to the hospital emergency room for observation. Fortunately, the child was released with no permanent damage.

One vs. One-half
New computer software was used to enter the directions for a cough medicine with a prescribed dose of 1-2 teaspoonsful. Instead, the new software printed a label that read 1/2 teaspoonful. The pharmacist did not check the label against the prescription and dispensed the product with the incorrect directions on the label.

Amoxicillin Directions
A pharmacist entered i cp q 8 h ear infection for an amoxicillin prescription. Due to a programming error, the computer printed Take 12 capsules every 8 hours for ear infection. The patient's mother recognized the error in the directions and brought the mistake to the pharmacist's attention. The software error was then rectified.

Quinine vs. Quinidine
The mnemonic Quin 200 was entered instead of Quind 200. The patient received quinine instead of the prescribed quinidine.

Methylprednisolone vs. Medroxyprogesterone
A pharmacist's keying error resulted in the filling and refilling of a prescription with methylprednisolone instead of medroxyprogesterone. Additionally, the patient's profile was not checked during the initial fill. The error was discovered when the female patient showed the prescription to her physician after she experienced breakthrough bleeding.

Digoxin Pediatric Elixir
Because the computer used in one facility was limited to entering doses in milligrams, a neonate's 20 microgram dose of digoxin first had to be converted to the equivalent milligram dose before it could be entered into the computer. A pharmacist incorrectly converted and then entered into the computer the 20 mcg dose as 0.2 mg. Consequently, the neonate received four 200 microgram doses of digoxin instead of the 20 mcg as specified in the order. The neonate experienced digoxin toxicity before the error was discovered.

Incorrect Patient
A prescription for 50 mg hydrochlorothiazide was entered into the computer correctly but the wrong patient was chosen from the computer generated profile list. The error was caught before the patient took a dose.

U-40 vs. U-100 Insulin Syringes
A pharmacist incorrectly selected U-40 insulin syringes (which are calibrated to measure 40 units of insulin per mL) on the computer instead of the intended U-100 syringes (which are calibrated to measure 100 units of insulin per mL) to refill a patient's prescription. By using the units calibration of the U-40 syringe to measure the U-100 insulin, the patient self administered an overdose.

Metoclopramide vs. Methychlothiazide
A pharmacist entered the mnemonic MET but chose methychlothiazide instead of metoclopramide from the retrieved computer generated list. After the patient took the methychlothiazide, the physician had difficulty restabilizing the patient's pre existing heart condition.

Tablespoon vs. Teaspoon
When a prescription with directions for 1 teaspoonful of an antibiotic suspension was entered into the computer, the abbreviation TBSP (for tablespoon) was selected instead of TSP (for teaspoon). This resulted in directions that read 3 teaspoonsful instead, and an overdose of the antibiotic was administered. The error could have been caught at the patient counseling phase had proper counseling been given.

These examples indicate that upon entry of new prescriptions, care should be taken in selecting choices from lists of patients and drugs. If "shorthand" directions are entered, be sure the entry is carefully checked for accuracy and for computer translation of the shorthand. Verification of the original order with the computerized patient record and the printed label can ensure that patients actually receive the correct product and dose, especially where refills are concerned. Patient counseling should be included as a final check for confirmation of the prescriber's order regarding the patient's identity, drug and strength, dosage, and frequency.