Rizatriptan is FDA-approved to treat acute migraine attacks with or without aura. It does not prevent future migraine attacks. Rizatriptan is also used off-label to treat cluster headaches.
Serotonin Agonist; Antimigraine drug
There are several physiological and molecular processes implicated in the pathophysiology of migraine. Vasodilation of intracranial extracerebral blood vessels, particularly those supplying the dura mater, has been associated with migraine pain. Activation of the trigeminovascular system leads to the release of vasoactive neuropeptides from the trigeminal nerve innervating the intracranial vessels and dura mater. Vasoactive neuropeptides cause perivascular inflammation and vasodilation in the periphery. Migraine-associated nausea and vomiting are thought to arise from the activation of central and nociceptive sensory neurons that project to autonomic brain-stem nuclei and higher subcortical and cortical pain processing centres. An imbalance in serotonin (5-HT) levels has also been documented: 5-HT binds to 5-HT1B and 5-HT1D receptors to promote trigeminal neuronal firing and vasoconstriction.
Rizatriptan is a selective agonist at the 5-HT1B and 5-HT1D receptors on intracranial blood vessels and sensory nerves of the trigeminal system. It binds to these receptors with high affinity.9 The exact mechanism of action of rizatriptan has not been fully elucidated; however, several documented pharmacological actions of rizatriptan may contribute to its antimigraine effects. Rizatriptan causes vasoconstriction of intracranial extracerebral blood vessels, which is thought to occur primarily via 5-HT1B receptors. Rizatriptan also inhibits nociceptive neurotransmission in trigeminal pain pathways. It attenuates the release of vasoactive neuropeptides by the trigeminal nerve, which is thought to occur via neurogenic and central 5-HT1D receptors. Rizatriptan inhibited neurogenic dural vasodilation and plasma protein extravasation in animal studies.
ORAL Acute migraine attacks: Adult: Initially, 10 mg. If ineffective, 2nd [dose should not be taken for the same attack. It symptoms recur after initial response, a further dose of 10 mg may be given. Doses should be separated by at least 2 hr. Max: 20 mg/24 hr. If patient is also taking propanolol, initiate w/ 5 mg. Max: 10 mg/24 hr. Ensure that the 2 drugs are separated by at least 2 hr.
Rizatriptan 5 mg should be used in patients taking propranolol. Ergotamine-containing or ergot-type medications (like dihydroergotamine or methysergide) and rizatriptan within 24 hours is contraindicated. Coadministration of rizatriptan and other 5-HT1 agonists within 24 hours of each other is not recommended. Rizatriptan should not be administered to patients taking MAO-A inhibitors and non-selective MAO inhibitors.
History of Ml, peripheral vascular disease, transient ishaemic attack, ischaemic heart disease or Prinzmetal’s angina; uncontrolled hypertension; basilar or hemiplegic migraine; severe hepatic or renal impairment. Adolescent <18 yr. Elderly; mild to moderate hepatic or renal impairment; coronary artery disease; pregnancy, lactation. May cause drowsiness. History of seizures. Ensure an interval of at least 24 hr after stopping an ergotamine compd & starting a serotonin (5-HT1) agonist.
Increased BP, chest pain, palpitation; skin flushing; dyspnoea; nausea, abdominal pain, dry mouth; dizziness, drowsiness, fatigue. Toxic epidermal necrolysis.
It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Migraine and tension-type headache are primary headache disorders that occur during pregnancy. No published experience exists with rizatriptan during breastfeeding. If rizatriptan is required by the mother, it is not a reason to discontinue breastfeeding; however, an alternate drug may be preferred, especially while nursing a newborn or preterm infant.
No overdoses of Rizatriptan were reported during clinical trials. Rizatriptan 40 mg (administered as either a single dose or as two doses with a 2-hour interdose interval) was generally well tolerated; dizziness and somnolence were the most common drug-related adverse effects. In addition, based on the pharmacology of rizatriptan, hypertension or other more serious cardiovascular symptoms could occur after overdosage. Gastrointestinal decontamination, (i.e., gastric lavage followed by activated charcoal) should be considered in patients suspected of an overdose with Rizatriptan.
Store in a cool and dry place below 30°C. Protect from light. Keep out of reach of children.
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