Major Interactions

Recently, pharmacies failing to address significant drug interactions has made national headlines. But while the pharmacists that failed to address these interaction are certainly at fault, to some degree we all share in the fault. Today’s healthcare world is regularly pushing providers to do more for less. The payor and the patient both want low cost, and with respect to pharmaceuticals, they often getting what they want.

The public’s frenzy for low cost pharmaceuticals has fueled the fire. Pharmacy reimbursement is almost exclusively based on the drug product dispensed, and reimbursement today often barely covers drug cost. Pharmacists are generally not paid for their clinical expertise.  In order to stay competitive, pharmacies have to increase prescription volumes while using fewer pharmacists. Instead of using a pharmacist to perform continuous medication monitoring or drug utilization review, pharmacies are increasingly relying on computers to help the pharmacist identify problems with drug regiments.

Today, pharmacies almost exclusively use a type of software generically referred to as pharmacy management system. Besides handling the record keeping for dispensing prescriptions, the package also includes screening for drug interactions, therapeutic duplication, drug allergies, and drug / disease issues. The problems identified by a software package like this will range from trivial issues with no clinical relevance to life-threatening problems. Because of the enormous volume of alerts generated by these systems, alert fatigue is a real concern.

But while computers can generally find problems, at this point they still lack the clinical expertise to make the important judgements required. A pharmacist still needs adequate time to evaluate the implications of the sometimes lengthy list of potential problems. Given the time, pharmacists can help ensure a patient will have positive therapeutic outcomes while minimizing the associated risks. To emphasize this, let us look at a brief tale from the counter.

We start out with a patient taking Oxybutynin and Nortriptyline. They have been taking this combination for some time now. Looking at the most recent refills, the only item noted by the computer based screening is a late refill on one of the medications. No drug interactions were flagged by the computer, but as it turns out this is not necessarily accurate. If the pharmacist looks at these two medications in a dedicated drug interaction reference, they find that there actually is an interaction:

Pharmacologic effects and plasma concentrations of Nortriptyline HCl Oral may be decreased by Oxybutynin Chloride ER Oral

The interaction is considered a MODERATE risk, with a delayed onset. The reference also notes that there is not a lot of documentation to support this interaction. In this case, the pharmacist recognized the interaction without the aid of the computer screening. The interaction poses minimal risk as the nortriptyline dose is generally titrated to the desired effect. The intervention might involve a brief discussion with the patient explaining the issue.

But the plot thickens: more recently, the oxybutynin was discontinued and a newer medication started. Myrbetric does flag as a drug interaction in the pharmacy management system, but again the system did not display an alert because it was set to only display moderate and severe interactions. The reference used by the software classified the interaction as minor.

But when using a dedicated interaction reference, the story is quite different: the interaction significance is classified as major.

Pharmacologic effects of Nortriptyline HCl Oral may be increased by Myrbetriq Oral. Elevated plasma concentrations with toxicity (e.g. QT prolongation/Torsades de Pointes) may occur.

Note that the effect on the nortriptyline is opposite that of the other drug. The overall risk is much higher for this type of interaction, and one of the listed consequences is Torsades de Pointes, a rare but very significant heart arrhythmia that can be fatal. Fortunately, the pharmacist was given adequate time to consider the new therapy, spotted the interaction, and addressed it with the patient and prescriber.

So the national headlines decrying pharmacists missing important interactions also serves to highlight how important having a pharmacist exercise their clinical judgment is to patient care. Perhaps the there is another interaction that needs to be addressed:

Interaction: poor reimbursement decreases pharmacist staffing.
Significance: Major
Onset: Delayed
Documentation: Strongly suspected

Effect: Ability of pharmacists to perform clinical activities is negatively impacted by current pharmacy reimbursement model focused on inexpensive drug product.

Be sure you make every encounter count!

Published by

Michael Deninger

Mike graduated from the University of Iowa with a BS in Pharmacy in 1991 and completed his Ph.D. in 1998. He has over 20 years of practice experience, over half of which is as a pharmacy owner. Areas of expertise also include technology in practice, including integration with data sources.

Discover more from The Thriving Pharmacist

Subscribe now to keep reading and get access to the full archive.

Continue reading