NTI drugs: caution for malpractice

Drug Store News, August 18, 1997 by Kenneth R. Baker

The latest topic in the pharmacy community involves what the Food and Drug Administration designates as narrow therapeutic index drugs, or NTI drugs.

The FDA lists approximately 25 drugs in this category, including aminophylline, carbamazepine, lithium carbonate, phenytoin, theophylline and warfarin sodium. The reason for listing a drug as an NTI drug is that there appears to be a narrow therapeutic range between the beneficial dose and an at-risk dosage.

My interest in the subject was piqued when I noticed many of the drugs listed as NTI drugs were the same as those frequently involved in claims against pharmacists. This is particularly noticeable in the mechanical dispensing error claims. Since 85 percent of the professional malpractice claims against pharmacists involve a mechanical error, this seemed to be an area worth considering for risk management.

The first step in risk management is identifying a problem.

How can pharmacists use the knowledge that certain drugs have been recognized to have a narrower dosage window and that some of these same drugs appear frequently in malpractice claims against pharmacists?

While I can not suggest a direct relationship, conservative risk management techniques seem worth discussing.

Stop and think

When receiving an order or a prescription for an NTI drug, pharmacists and technicians should train themselves to stop and think for an additional few moments. Whenever we do repetitive tasks, we get into an automatic mode. This is the cause of many claims.

We can get out of this automatic mode of thinking by stopping, checking the prescription an additional time and, particularly, rechecking the NDC number. This will check for the correct drug and correct strength.

A drug seen often in mechanical dispensing errors is warfarin. A common error involving warfarin is the incorrect strength used, i.e. the prescription calls for 2 mg., but 5 ma. tablets are dispensed. While such a mistake with any drug may cause injury to the patient, when the mistake occurs with drugs shown to have a narrow range between therapeutic benefit and risk, a special alarm is warranted.

This difference may not be long lost on plaintiff lawyers. I have seen plaintiff lawyers request punitive damages in such cases, alleging the pharmacist had a higher duty of care when dispensing these drugs. While I do not subscribe to this theory, caution may be the best answer.

The pharmacist should always recheck the directions on all labels, but should particularly do so when using NTI drugs.

To get out of the automatic mode when handling NTI drugs, the pharmacist should develop a different procedure and thinking process. One way is to mark that part of a shelf containing NTI drugs in a special manner that is immediately noticeable, such as colored tape with "NTI" written on it. When a pharmacist or technician approaches that part of the shelf marked as "NTI," the pharmacist or technician stops and checks one more time.

In addition, the pharmacist or the technician may write "NTI" on the prescription, so any pharmacist making the final check is aware and can give special attention while checking.

An obligation to counsel

Counseling is an important element in today's pharmacy practice. The pharmacist can be an even more effective part of the patient's care if the patient is informed of how and when to best use the drug. This is particularly important for a drug with a narrow therapeutic index, since the method and timing of administration may be more critical. When an NTI drug is dispensed, a pharmacist should take more time to be certain the patient recognizes the importance of taking each dose as prescribed.

Increasingly, courts have recognized a pharmacist's duty to warn a patient of the nature and dangers of prescription drugs. As the potential for harm increases, the degree of care used may also increase.

In the 1994 Tennessee Supreme Court case of Pittman vs. Upjohn, 890 S.W.2d 425, (1994), the court found the pharmacy defendant had a duty "greater than merely filling the physician's prescription correctly." The court said "the pharmacy, as well as the physician, owed [the patient] the duty to warn" of the "symptoms and dangers of complications that might arise from the use of micronase."

In this case, the court found neither the physician nor the pharmacy liable for the brain damage suffered by the adult grandson of the patient, because it was not foreseeable the adult grandson would accidentally take his grandmother's micronase. The court indicated, however, that as the probability of harm increases, the degree of care owed by the professional increases.

Errors involving NTI drugs may present greater risks. Pharmacists need to recognize the potential harm with all drugs, but should be particularly alert to NTI medications.

We can never practice in a manner to avoid all errors. No matter what we do, there will be times, especially when we are busy, when we get into an automatic mode of thinking. Such a mode is natural and allows us to do some tasks quicker and with less stress. Some time during each day, however, we need to break out of this mode of thinking. Training ourselves to deal in this way with NTI drugs is a good way to handle this human tendency.