Coprescription of triptans with potentially interacting medications: a cohort study involving 240,268 patients

Abstract

Background: Little information exists about the actual prescription of triptans within large, geographically diverse populations, in terms of demographic characteristics and co-prescriptions with other medications with potential interactions.

Objectives: To investigate the demographic characteristics associated with triptan use, and examine the rate of co-prescription of triptans with specified pharmacologic agents with the potential for drug interactions.

Methods: This study examined the rate of co-prescription of triptans available in the US up to May 2001 (sumatriptan, naratriptan, rizatriptan, and zolmitriptan) with specified agents with potential for drug interactions. A cohort of 240,268 patients receiving pharmacy benefits from Merck-Medco (N = 65 + M) was followed over a one-year period. This analysis included patients who received at least two triptan prescriptions during the study (6/00-5/01). Ninety-one percent of the cohort remained on the same triptan during the study period. 'Co-prescription' was defined as any fill for a medication that was contraindicated or could potentially adversely interact with a triptan, obtained between and during the first and last triptan fills throughout the study period.

Results: Mean patient age was 43 (SD +/- 11.6) and 82% were female. Twenty-one percent were co-prescribed selective serotonin reuptake inhibitors, reflecting the considerable co-morbidity of migraine and depression. Patients taking triptans were almost never co-prescribed monoamine oxidase inhibitors (0.02%), and co-prescription of ergots was also low (1.45%). Less than one percent (0.45%) received cimetidine while taking zolmitriptan, while 2.7% of patients taking rizatriptan 10 mg also took propranolol. While agents unavailable in the U.S. were not evaluated in this cohort, six percent of patients were treated with potent CYP 3A4 inhibitors, which would not be expected to cause any problems with the triptans in the survey. However, such agents are specifically contraindicated for use with one triptan (eletriptan), recently launched in the EU, suggesting that continued vigilance will be necessary to avoid coprescription of medicines with the potential for producing adverse side effects.

Conclusions: Triptan use mirrors migraine demographics. The frequency of co-prescription of triptans with SSRIs is about 20%. Continued vigilance will be necessary to avoid co-prescription of medicines with the potential for producing adverse drug events.