Drug-Drug Checking

The new medication is checked against existing medications in the patient's record for any interactions. Interaction checking is carried out on the basis of generic names and generic grouping of the drugs in the database. Checks are also made to determine if the drug, or another drug in the same class, is already prescribed for the patient.

Prompts to warn you of drug-drug interactions only appear at the time a new drug is added to the patient's medication list. If you choose to prescribe the new item, you will not be prompted again upon printing a repeat prescription for either of the two items.

There are a number of drug-to-drug interaction types checked by the Clinical program:

The first is a simple reminder. This is given if a patient is prescribed a drug from the same group as a drug already on their current medication list. A warning window is displayed asking if you wish to continue prescribing the medication. A similar reminder is given whenever an antibiotic is prescribed to a patient on the Oral Contraceptive pill.

Interactions between drugs that are of more significance are divided into a number of categories. A warning message describing the general form of the interaction is displayed and the prescriber must choose whether to continue with the prescription of the new medication. For some interactions, the default option is to Proceed. This occurs where caution should be observed in using the two drugs simultaneously, for example a benzodiazepine with an antihistamine.

Interaction checking occurs where the addition of the new drug may require adjustment of the dose of a drug that is already prescribed, or where the dose of the new drug may need to be monitored because of a drug that is already being taken, for example adding PHENYTOIN and THEOPHYLLINE.

For more serious interactions, the default option is to cancel the prescription of the new drug. These are interactions where it is best not to use the two drugs together without careful consideration of the potential consequences, for example WARFARIN and ASPIRIN, or TERFENADINE and KETOCONAZOLE.

If you wish to see more information regarding the interaction which has been flagged, click PI on the prompt to open the full Prescribing Information sheet for the item being prescribed.

As with allergy checking, it is almost always possible to override the default option. Ultimately the decision on whether to prescribe a particular combination of drugs is left up to the clinical judgment of the practitioner using the program.

As the new drug is checked against every drug on the patient's current list, it is possible to have multiple warnings. If you choose to continue at one warning, that does not stop the program from checking all items on the list, as there may be a more serious interaction with another medication on the list.

It is possible to view the current list of interactions for any drug by looking it up in MDref. Once in MDref, click Interaction to see the list of interactions that is checked for when that drug is prescribed. This information is updated every time the MDref drug update is installed.