No Clinically Significant Drug-Drug Interaction Between Rimegepant and Galcanezumab
There is no clinically significant drug-drug interaction between rimegepant and subcutaneous galcanezumab, and these medications can be safely used together for migraine management. 1
Evidence for Concomitant Use
Safety Data from Clinical Studies
A prospective safety substudy specifically evaluated the combination of rimegepant with CGRP monoclonal antibodies (including galcanezumab) and found the combination to be well tolerated with no safety concerns identified. 1
In this study, 13 patients used rimegepant 75 mg as needed (up to once daily) while receiving stable doses of CGRP monoclonal antibodies, including 2 patients specifically on galcanezumab. 1
Only 38% of patients reported any adverse events, with nasopharyngitis being the most common (15%), and no serious adverse events, discontinuations, or liver enzyme elevations occurred. 1
Mean exposure was 7.8 doses of rimegepant over 4 weeks (total 224 doses across all patients), demonstrating safety with repeated concomitant use. 1
Mechanistic Rationale for Safety
Both medications target the same CGRP pathway but through complementary mechanisms that do not create pharmacokinetic or pharmacodynamic conflicts. 2
Galcanezumab is a humanized monoclonal antibody that directly binds to the CGRP peptide itself, preventing it from activating its receptor and reducing free, bioavailable CGRP. 2
Rimegepant is an oral CGRP receptor antagonist that competitively blocks the CGRP receptor without affecting CGRP peptide levels. 2
These distinct mechanisms allow for concurrent use: galcanezumab reduces circulating CGRP ligand while rimegepant blocks any remaining CGRP from binding to receptors. 3
Clinical Application
Treatment Strategy
Use galcanezumab 120 mg subcutaneously monthly (after 240 mg loading dose) for migraine prevention, with rimegepant 75 mg orally as needed for acute breakthrough migraine attacks. 4, 1
Galcanezumab has a "strong for" recommendation from the VA/DoD for prevention of episodic or chronic migraine based on demonstrated reductions in mean monthly migraine days. 4
Rimegepant can be used up to once daily for acute treatment without dose adjustment when combined with galcanezumab. 1
Monitoring Considerations
No specific laboratory monitoring is required for this combination beyond standard clinical assessment. 1
Monitor for typical adverse effects of each medication independently: injection-site reactions with galcanezumab and nausea with rimegepant. 5, 6
The combination does not increase risk of hepatotoxicity or other serious adverse events based on available safety data. 1
Important Clinical Context
Comparative Efficacy
A head-to-head trial demonstrated that galcanezumab and rimegepant have similar efficacy for migraine prevention (62% vs 61% achieving ≥50% reduction in migraine days), though this compared rimegepant used preventively every other day rather than acutely. 7
Both medications can be safely combined with other migraine preventive treatments acting on different targets. 3