DUR: The Drug-Drug Interaction Alert: A Better Understanding
The Medi-Cal Drug Use Review (DUR) program oversees the electronic alerts sent to pharmacy providers when a Medi-Cal drug claim processed through the Point of Service system interacts with certain clinical indicators. These indicators are updated periodically, and occasionally the logic for an alert changes. The Drug-Drug (DD) Interaction Alert has undergone considerable change in the past two years. Providers were notified when the changes first occurred, but because of the complexity of the topic, an update is warranted.
Drug-Drug Interaction Module
The data references DUR uses for the DD alert originate from First DataBank
(FDB). The current FDB
Drug-Drug Interaction Module (DDIM) is a clinically reviewed drug-drug
interaction module. This module contains only the most clinically significant
drug-drug interactions. A drug interaction is defined as a patient’s use of two
or more drugs that create a different pharmacological response from what is
expected when the agents are given separately. This definition includes
synergistic and antagonistic effects but excludes additive effects. Clinical
severity and the quantity and quality of documentation are some of the criteria
considered when determining the inclusion of a drug interaction in the DDIM.
Frequency of occurrence is not part of the criteria for addition to the module.
Severity Level 1 Drug Interactions
The DDIM uses four different severity levels to classify drug interactions, but
DUR only sends out alerts on the most severe interactions – Severity Level 1
drug interactions. This is mainly to ensure that the message to the pharmacist
is clear and consistent. As defined by FDB, Severity Level 1 drug interactions
are those drug combinations that are clearly contraindicated in all cases and
should not be dispensed or administered concurrently to the same recipient. A
manufacturer’s label indicating the contraindication is sufficient to warrant
including a drug combination in this category, regardless of clinical evidence
or lack thereof.
Alerts Meant as Aids to Pharmacists
Pharmacists override about 81 percent of the DD alerts sent by the DUR
system. In other words, 19 percent of all DD alerts cause sufficient concern
that the pharmacist chooses not to fill the prescription. Evaluating these
alerts can be difficult because DD interactions are not predictable except for
their severity. Pharmacists must always exercise caution and careful assessment
before choosing to dispense interacting drugs.
Ultimately, it is the pharmacist’s decision whether or not to dispense interacting drugs. The DUR alerts are meant to provide as much clinical advisory support as possible. The pharmacist, in conjunction with the prescribing physician and the recipient, must balance the risk to the recipient against the potential benefit the recipient derives from taking potentially interacting medicines.