Using Two CGRP-Blocking Migraine Drugs at the Same Time Appears Safe in This Small Study

Combining the oral CGRP receptor antagonist rimegepant (75 mg as needed) with injectable CGRP monoclonal antibodies (erenumab, fremanezumab, or galcanezumab) for migraine was well tolerated in 13 patients over approximately 10 weeks. A total of 224 rimegepant doses were taken. Five patients (38%) reported mild adverse events, most commonly nasopharyngitis. Three patients had mild-to-moderate events considered potentially treatment-related. No serious adverse events, no treatment discontinuations, and no liver enzyme elevations occurred. This provides the first systematic safety data for using two different CGRP-targeting therapies simultaneously.

This was a substudy nested within a larger multicenter, open-label, long-term rimegepant safety study. Thirteen patients with 2-8 monthly migraine attacks who were already on stable CGRP mAb therapy (erenumab n=7, fremanezumab n=4, galcanezumab n=2) took rimegepant 75 mg as needed (up to once daily) for acute treatment over 12 weeks. Safety was assessed through adverse event monitoring and liver enzyme testing.

Many migraine patients use a CGRP antibody injection monthly for prevention but still need acute treatment when breakthrough attacks occur. Using a gepant (like rimegepant) for these attacks means both the preventive and acute treatments block the same CGRP pathway, raising theoretical safety concerns about "double CGRP blockade." This study provides reassurance that the combination appears safe — an important practical finding because it validates a treatment approach clinicians are already using in practice.

The approval of both CGRP antibodies (for prevention) and gepants (for acute treatment) created an obvious clinical question: can patients use both? Both drug types target the CGRP pathway but through different mechanisms — antibodies block the peptide or receptor for weeks, while gepants provide short-term receptor blockade. This study is one of the first to formally assess the combination, and the reassuring safety data supports what many headache specialists were already doing in practice. Larger studies have since been conducted to confirm these preliminary findings.

The sample size of 13 is very small — too small to detect rare safety signals. The study is open-label with no control group. The 12-week duration may not capture long-term safety concerns. The study cannot assess whether dual CGRP blockade reduces efficacy of either drug. The highly selected patient population (stable on CGRP mAb, moderate attack frequency) may not represent all patients who would use this combination in practice.