Medications for migraines: Nursing pharmacology

Migraines are a specific type of pounding or pulsating headache that’s typically localized to one side of the head, and is often associated with additional symptoms like photophobia, phonophobia, nausea, or even vomiting. As preventative therapy, some clients may take beta blockers like metoprolol, antiepileptics like topiramate, or tricyclic antidepressants like amitriptyline.

On the other hand, acute treatment of migraines involves managing the symptoms with abortive agents, which can be broadly divided into four classes; ergot derivatives, triptans, ditans, and calcitonin gene-related peptide or CGRP receptor antagonists, which are also used as preventive therapy.

Starting with ergot derivatives, these include ergotamine and dihydroergotamine. Ergotamine can be administered in sublingual tablets, while dihydroergotamine can be injected intramuscularly or intravenously, or used as a nasal spray. Once administered, ergot derivatives work by binding to serotonin and alpha-adrenergic receptors on the blood vessels in the brain, causing them to constrict. And that helps decrease the pain because vasodilation of these blood vessels seems to be a trigger for pain receptors, causing the migraine in the first place.

However, ergot derivatives not only cause vasoconstriction of the blood vessels in the brain, but also blood vessels all around the body, which can cause hypertension. Vasoconstriction of coronary blood vessels in the heart can also bring about a type of chest pain called angina, which, in severe cases, can get complicated with arrhythmias or even myocardial infarction. At the same time, ergot derivatives stimulate serotonin receptors in the vomiting center of the brain, so they can trigger nausea, vomiting, or gastrointestinal disturbances. Itching of the skin, as well as leg weakness, numbness, tingling and muscle pain in arms and legs are also common side effects.

Ergot derivatives also stimulate contraction of the smooth muscles of the uterus, which can lead to premature labor or miscarriage in pregnant clients. Finally, a situation called ergotism happens when clients intoxicate with ergot derivatives; this manifests mainly with spasms, seizures, psychiatric and gastrointestinal symptoms, blood pressure changes, and gangrene in the hands and feet due to vasoconstriction. It’s also important to point out that overuse of ergot derivatives results in dependence, causing withdrawal symptoms or rebound headaches when discontinued abruptly.

Now, ergot derivatives are contraindicated in children and elderly clients, as well as during pregnancy and breastfeeding. They should also be avoided in clients with cardiovascular disease, hypertension, or peripheral vascular disease, as well as in those with Raynaud phenomenon or Buerger syndrome. Finally, ergot derivatives should be used with caution in clients with severe hepatic or renal disease.

Regarding interactions, ergots have a boxed warning against their use in combination with potent CYP34A inhibitors, such as protease inhibitors or macrolide antibiotics, since they can cause increased levels of ergots, causing vasospasm, peripheral ischemia, and cerebral ischemia.

Next, there are triptans and ditans. Triptans are categorized as serotonin 5-HT 1B/1D receptor agonists, and include sumatriptan, naratriptan, rizatriptan, zolmitriptan, almotriptan, frovatriptan, and eletriptan; on the other hand, ditans are categorized as a serotonin 5-HT1F receptor agonist, and the most common one is lasmiditan. All of these medications can be taken orally, but this may be impractical for clients who experience nausea or vomiting during the migraine attack. For these situations, subcutaneous injections or a nasal spray of sumatriptan are available.

Similarly to ergot derivatives, both triptans and ditans bind to selective serotonin receptors, namely 1B and 1D for triptans, and 1F for ditans, which are located in blood vessels of the brain and trigeminal nerve, causing vasoconstriction and decreased inflammation. As a result, these medications help stop the migraine attack and relieve its symptoms.

Side effects of triptans and ditans are generally mild, and include fatigue, dizziness, sedation, weakness, and flushing. In addition, subcutaneous administration can cause mild pain, tingling, numbness, and a cold or burning sensation at the site of injection. Less commonly, triptans and ditans can also cause gastrointestinal disturbances, as well as discomfort in the mouth, jaw, or throat, chest tightness, hypertension, and even myocardial infarction. Finally, ditans can cause CNS depression, potentially leading to a decreased mental and physical function; in addition, ditans are also associated with serotonin syndrome.

As far as contraindications go, triptans and ditans should not be used in clients with a history of cardiovascular disease or uncontrolled hypertension. In addition, these medications are contraindicated for intravenous use, as well as for concurrent use with ergot derivatives. Precautions should be taken during pregnancy and breastfeeding, as well as in children and elderly clients. Additionally, these medications should be used with caution in clients with hypercholesterolemia, obesity, diabetes, and hepatic or renal disease. Finally, triptans should be used with caution in clients with seizure disorder.

Finally, there’s a new class of medications used to treat migraines, called CGRP receptor antagonists. The most commonly used medications of this group include erenumab, which is a monoclonal antibody that is administered by subcutaneous injection; as well as the medications ubrogepant and rimegepant, which are taken orally. Once administered, CGRP receptor antagonists target and block either the calcitonin gene-related peptide, or its receptor, which is located on the brain stem. This peptide is involved in the transmission of sensory impulses like pain, temperature, and touch throughout the trigeminal nerve. So, basically, CGRP receptor antagonists block these sensory impulses, either preventing or stopping the migraine attack.

CGRP receptor antagonists are quite safe, with mild side effects like pain or redness at the injection site for erenumab. In addition, these medications may cause severe constipation, especially when combined with medications that decrease gastrointestinal motility, such as antidiarrheal medications and opioids. Lastly, erenumab may cause hypertension or make existing hypertension worse. Finally, CGRP receptor antagonists should be used with caution in pregnant or breastfeeding clients, as well as in clients with hypertension or risk factors for hypertension, and in those with latex allergy.

All right, when a client has been diagnosed with migraines, they could be prescribed a selective serotonin receptor agonist like sumatriptan. Before administering this medication, be sure to review their chart, checking for any active cardiovascular disease like angina or uncontrolled hypertension.

Then, perform a focused baseline assessment, including a description of their migraine, its location, time of onset and frequency, severity and type of pain, as well as presence of aura, and any additional symptoms like photophobia, phonophobia, nausea, or vomiting. Also, ask your client if there are any known triggers for the migraine. Lastly, review their most recent laboratory test results, including renal and hepatic function, and for clients of childbearing age, be sure to confirm they are not pregnant.