Antimigraine Medications Health Article

Definition

Antimigraine medications are drugs that are given to lower the risk of a severe migraine attack or to reduce the severity of the headache once an attack begins.

Purpose

Treatment that is given to stop or ease the pain of a migraine headache after it has started is known as acute or abortive treatment.

Preventive treatment for migraine headaches is called migraine prophylaxis or prophylactic therapy. Prophylactic medications are taken when the patient is not having a headache. They have three purposes:

• lower the frequency and severity of the patient's headaches
• make acute migraines more responsive to abortive treatment
• improve the patient's overall quality of life

Not all patients with migraines need prophylactic treatment. Most doctors, however, recommend prophylactic medications in the following circumstances:

• The patient has two or more migraines per month, with disability lasting three or more days
• Acute treatment is contraindicated or is ineffective
• The patient has been using abortive medications more than twice a week
• The patient has a complex form of migraine such as hemiplegic or basilar migraine
• The patient is at risk of permanent neurologic injury from acute attacks

Abortive medications

The following interactions have been reported for abortive medications:

• Triptans: All the triptans narrow coronary arteries by 10–20% and will intensify the effects of other vasoconstrictive drugs, including the ergot alkaloids and drugs given for vascular disorders. With the exception of naratriptan, the triptans cannot be taken together with MAO inhibitor antidepressants because of the risk of a rapid and dangerous rise in blood pressure. Rizatriptan has been reported to interact with the beta-blocker propranolol.
• Ergot alkaloids: Cannot be taken together with the triptans. Ergot alkaloids should not be taken together with methysergide because of an additive effect. Should not be taken together with other vasoconstrictive drugs (including beta-blockers, some acid-reducing drugs, some antibiotics, and some antifungal drugs) because of the increased risk of gangrene.
• NSAIDs: These drugs tend to prolong bleeding time and should be used cautiously by patients taking blood-thinning medications. Alcoholic beverages increase the risk of gastric ulcers or bleeding from the use of NSAIDs. In addition, patients should not take more than one NSAID at a time.
• Combination analgesics: These drugs should not be used together with MAO inhibitors or other drugs that contain acetaminophen. They will intensify the actions of other drugs that may cause drowsiness, including alcohol, TCAs, antihistamines, sedatives, and muscle relaxants.
• Antiemetics: Should not be taken together with alcohol (intensifies central nervous system depression), tricyclic antidepressants (lowers blood pressure), or phenobarbital. Patients taking anticonvulsants may need to have their dosage increased if they are given an antiemetic.

Prophylactic medications

The following interactions have been reported for prophylactic medications:

• Anticonvulsants: Valproic acid will intensify the effects of other anticonvulsants, barbiturates, alcohol, and anti-depressants. It interacts with aspirin and heparin to increase the risk of spontaneous bleeding. Gabapentin intensifies the effects of morphine, but is less effective when taken together with antacids.
• Beta-blockers: Antacids decrease the absorption of beta-blockers. Cimetidine is reported to intensify the actions of beta-blockers. Beta-blockers may interact with insulin or other diabetes medications to produce high blood sugar levels. They should not be taken together with MAO inhibitors because of the risks of severe high blood pressure. Cocaine also increases the risks of high blood pressure or other heart problems in patients taking beta-blockers.
• Calcium channel blockers: Verapamil may cause low blood pressure or dizziness if taken together with alcohol. It should not be taken with beta-blockers because of a risk of congestive heart failure or slowed heartbeat. Verapamil also intensifies the effects of cyclosporine and lithium.
• TCAs: Should not be taken together with barbiturates, alcohol, sleeping medicines, or sedatives because they intensify central nervous system depression. They may also intensify the effects of certain antibiotics and anti-fungal medications. They may interact with bupropion to produce seizures. TCAs should never be taken with MAO inhibitors or SSRIs because of the risk of serotonin syndrome, a potentially fatal condition marked by fever, rapid changes in blood pressure, sweating, hyperreactive reflexes, delirium, nausea, vomiting, and coma. Serotonin syndrome takes its name from the overly high levels of serotonin in the patient's nervous system that are produced by these drug combinations.
• SSRIs: Should never be taken together with other anti-depressant medications because of the risk of serotonin syndrome. They may increase the patient's drowsiness if taken together with antihistamines, sleep medications, opioid analgesics, and muscle relaxants. Patients taking insulin or other diabetes medications may need to have their dosage adjusted if they are also taking an SSRI. SSRIs should not be taken together with herbal preparations used as mild tranquilizers, particularly compounds containing valerian or St. John's wort.
• Serotonin antagonists: Methysergide should not be taken together with ergot alkaloids or triptans because it intensifies their vasoconstrictive action. Patients taking this drug should give up smoking for the same reason. In addition, methysergide has been reported to counteract the pain-relieving effectiveness of opioid analgesics.