Migraine Treatment Landscape and the Role of the Pharmacist - Episode 9
Migraine Management: Role of the Pharmacist
What community pharmacists need to know about migraine treatment and their role in educating and managing patients.
Mark Percifield, PharmD: Jennifer, what would you describe as some of the key roles of the pharmacist in treating migraine?
Jennifer L. Mazan, PharmD: When a patient comes in and consults a pharmacist regarding a migraine, it’s important to ask a lot of questions first, to find out what is going on with the patient and gather information. We want to get their headache history, symptoms, frequency, and triggers, if they’re aware of them. We want to know the aggravating and remitting factors and frequency of taking analgesics. We want to find out if this is a migraine or if it’s a medication overuse headache. By getting that information, the pharmacist can make an appropriate assessment and recommendation, and provide patient education. As Amy [R. Dunleavy, PharmD], discussed earlier, regarding selection of OTC [over-the-counter] therapy, there are options. If it’s a mild to moderate migraine, they have combination products, such as acetaminophen, caffeine, and aspirin. One of the OTC NSAIDs [nonsteroidal anti-inflammatory drugs] would be a good place to start. One of the most important things we need to stress to patients when recommending an OTC analgesic is to make sure they’re not taking it more than 2 days per week. We want to stress that and limit that.
If they find that they’re taking it more than 2 days a week, then it’s time for a referral to a physician. They need to get further evaluation, and perhaps get a different medication that would be more effective. We must explain to the patients that by taking the analgesic more than twice a week, they’re at risk for the medication overuse headache. We want to explain what that is and how to prevent it. If they find that the OTC medications aren’t enough, or they’re having significant quality of life decreases, they should see a physician. If they can’t go to work and they’re missing a lot of days, even if they get some relief from the over-the-counter analgesic, they should go to a neurologist or their primary care doctor and get further evaluated. They need to get on a different medication that would be more effective for them. We can also talk to them about adherence and the importance of taking their preventative medications daily, and it’s only going to work if they do take preventative medications daily. We can also help with affordability, help them find a savings card or navigate the prior authorization landscape to guide them if they’re having trouble affording some of those prescription medications.
Mark Percifield, PharmD: Tim, is there anything that we should monitor for drug interactions or contraindications as a pharmacist?
Timothy Smith, MD, RPh, FACP, AQH: As with all therapeutic areas, there are several things that we need to be on the lookout for. Drug interaction is always a concern for most drug categories, especially for the acute therapies, like the triptan class, which is most often affected by the cytochrome P453A4 [CP453A4] isoenzyme concern. This would be your azole antifungals, macrolide antibiotics, and some antiretroviral therapies, principally the ones that we look at as inhibiting. For the triptans, eletriptan has its sole metabolic pathway through cytochrome 3A4 isoenzyme. For the others, both rimegepant and ubrogepant have cytochrome P453A4 isoenzyme pathways for metabolism. On the other hand, lasmiditan and the other triptans do not. We are most concerned about the CYP3A4 pathway. There are some minor concerns for PGP [P-glycoprotein] pump inhibition. Eletriptan is also affected and carried by that efflux transporter, and inhibition of that could lead to toxic levels of eletriptan. We’re talking about these antiretroviral drugs and some of the strong azole antifungals for that transporter as well. The lasmiditan is also a substrate for that transporter, so inhibition of the PGP pump is a concern there. As far as the triptans, there are 3 that are metabolized by the monoamine oxidase A system in the liver: Sumatriptan, zolmitriptan—at least, with an active metabolite—and then rizatriptan. The only 1 that comes with any kind of significant dosing recommendations is rizatriptan, and that’s due to the the presence of propranolol, which is frequently used as a migraine prophylaxis agent. For patients who are on propranolol for migraine prophylaxis, the recommendation is that rizatriptan, or Maxalt, be limited to a 5 mg dose as opposed to the 10 mg dose that most adults can take.
From a prophylaxis standpoint, Jennifer covered the ones for the small molecular weight antibodies, for the most part. Then we talked about the monoclonal antibodies, the CGRP [calcitonin gene-related peptide] monoclonals, being antibodies, are metabolized by the reticuloendothelial system. That opens you up to not having to worry so much about drug interactions. There are no real pharmacodynamic reactions to worry about. What I mean by that is they’ve been studied, since they prevent vasodilation. There is a concern that, if you combine a vasoconstrictor with them, you could get a pharmacodynamic effect. When combining them, for example, with triptans, the drug-drug interactions did not lead to any evidence of vasoconstriction, elevated blood pressures, chest pain, shortness of breath, EKG [electrocardiogram] changes or any changes in the pulse or other vital signs. Those are the seminal ones that we want to take into account when we look at both acute medication and preventive therapies in terms of drug interactions and in the treatment of chronic conditions.
Transcript edited for clarity.