Study: Drug-drug interaction warning letters work

Alerting practitioners on the dangers of a Plavix/PPI combination reduces number of patients on both therapies

ST. PAUL, Minn. — A letter educating healthcare providers regarding a drug-drug interaction between prescription anticlotting drug Plavix (clopidogrel) and a proton-pump inhibitor has resulted in a reduction in the number of patients combining the two therapies, according to a new study by Prime Therapeutics released Monday.

Recent data has shown the use of some PPIs in combination with clopidogrel can increase a person’s risk for clopidogrel failure and a subsequent cardiac event. Current guidelines suggest providers re-evaluate the need for PPI therapy in patients taking clopidogrel and consider recommending another type of heartburn medication as an alternative treatment.

Researchers from Prime and one of its Blue Cross and Blue Shield clients used a retrospective drug utilization review to analyze claims data from a 1.3 million-member commercial insurer. From this, researchers determined 1,316 members actively were combining clopidogrel with a PPI. A letter then was sent to healthcare providers alerting them of the potentially unsafe drug use and requesting the providers re-evaluate the need for PPI therapy in their patients. The study also tracked a control group of 2,740 patients who met intervention criteria but whose providers did not receive a letter.

At 180 days post-letter, actively enrolled members in both groups were assessed for the presence of a PPI, clopidogrel or both. This analysis showed a significant absolute 7.5% point reduction in the number of members who were combining PPIs and clopidogrel when their healthcare providers received the letter, compared with the control group.

“When patients or physicians are unaware of how drugs can react with one another, they are potentially putting themselves at risk for greater harm and health complications,” stated Patrick Gleason, director of clinical outcomes assessment for Prime. “This study shows that insurers, in partnership with pharmacy benefit managers, can increase member safety using simple and cost-effective tactics to significantly reduce the incidence of concurrent clopidogrel and PPI therapy, and ensure patients continue to receive safe, high-quality care.”

Details of the study will be presented April 29 at the Academy of Managed Care Pharmacy’s 23rd Annual Meeting. The published study abstract can be found in the Journal of Managed Care Pharmacy.

In related news, a recent study sponsored by Takeda Pharmaceuticals North America indicated that its PPIs Dexilant (dexlansoprazole) and Prevacid (lansoprazole) may have less of an inhibiting effect on Plavix than AstraZeneca’s Nexium (esomeprazole).


- 3:30 PM
mrisko says

Based on the consensus recommendations from the 3 organizations and endorsed by their boards published this past December, if the patient is defined to be at risk, the risk/benefit ratio should be determined, and if the patient is determined to be at significant GI risk (mod-severe), using a PPI (any PPI) seems most reasonable. The consensus group did not come down on the side that just omeprazole should be avoided, and felt that there was no significant cardiovascular risk identified for any of the PPIs when coprescribed with clopidogrel. Thus, although pharmacokinetic and pharmacodynamic data suggest varying inhibition by different PPIs of the enzyme systems necessary to convert clopidogrel to its active form, there is no good evidence that these differences on surrogate markers translate into meaningful differences in clinical outcomes. No prospective - head to head trials directly compare the clinical events of different PPIs in patients treated with clopidogrel.

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