Drug information of Rizatriptan
Mechanism of effect
Three distinct pharmacological actions have been implicated in the antimigraine effect of the triptans: (1) stimulation of presynaptic 5-HT1D receptors, which serves to inhibit both dural vasodilation and inflammation; (2) direct inhibition of trigeminal nuclei cell excitability via 5-HT1B/1D receptor agonism in the brainstem and (3) vasoconstriction of meningeal, dural, cerebral or pial vessels as a result of vascular 5-HT1B receptor agonism.
Rizatriptan is a selective agonist of serotonin (5-hydroxytryptamine; 5-HT) type 1B and 1D receptors.
Absorption:Rapid following oral administration. Bioavailability is 45%. Food has no effect on the bioavailability of rizatriptan. However, administering rizatriptan with food will delay by 1 hour the time to reach peak plasma concentration.Protein binding:14%. Rizatriptan is metabolized by monoamine
oxidase A isoenzyme (MAO-A) to an inactive indole acetic acid metabolite. Approximately 14% of an oral dose is excreted in urine as unchanged rizatriptan while 51% is excreted as indole acetic acid metabolite, indicating substantial first pass metabolism. Half life:2-3 hours
Drug indicationsthe acute treatment of migraine with or without aura in adults , acute treatment of migraine with or without aura in pediatric patients 6 to 17 pediatric patients 6 to 17 years old.
Usual Adult Dose for Migraine
Use only after a clear diagnosis of migraine has been established Initial dose: 5 mg or 10 mg orally, once -Provided there has been a response to first dose,
a second dose may be administered at least 2 hours later if migraine returns. Maximum dose: 30 mg in a 24-hour period Usual Pediatric Dose for Migraine
Use only after a clear diagnosis of migraine has been established 6 years or older and weight less than 40 kg:
-Initial dose: 5 mg orally once 6 years or older and weight 40 kg or greater: -Initial dose: 10 mg orally once Maximum: 1 dose in any 24-hour period
Drug contraindicationshypersensitivity to drug or its components. , Uncontrolled hypertension , Concomitant with MAOIs , history of myocardial infarction , angina , Hemiplegic migraine , basilar migraine
Side effectsnausea , Headache , chest pain , dry mouth , dizziness , fatigue , Blurred vision , rash , flushing , Cold Extremities , asthenia , urticaria , Hypertension , cardiac arrhythmias , paresthesia , somnolence , Tinnitus
InteractionsDextromethorphan , Dihydroergotamine , Ergotamine-C , Propranolol , Sumatriptan , Sibutramine , Citalopram , Fluvoxamine , Dexfenfluramine , Levomilnacipran , tropisetron , eletriptan , Palonosetron , Sufentanil , Alfentanil , Lorcaserin , Desvenlafaxine , Cyclobenzaprine , Buprenorphine , Tapentadol , Pethidine , rasagiline , Almotriptan , Fluoxetine
1-Cerebral hemorrhage, subarachnoid hemorrhage, and stroke have occurred in patients treated with 5-HT1 agonists, and some have resulted in fatalities. 2-For patients with coronary artery disease (CAD) risk factors, a
cardiovascular evaluation should be performed prior to initiating therapy; for patients who have satisfactorily completed a cardiovascular evaluation, consider administering first dose in a medically supervised setting and performing an ECG immediately following administration.
3-Use with caution; dose adjustment may be considered in patients with severe hepatic impairment, however, no specific guidelines have been suggested.
Points of recommendation
1-This drug should be used only where a clear diagnosis of migraine has been established; if a patient does not respond, the diagnosis of migraine should be reconsidered before treating subsequent attacks.
2-ECG monitoring should be considered in the interval following the first dose in patients with risk factors for coronary artery disease (CAD) who have satisfactorily completed a cardiovascular evaluation, consider periodic cardiovascular evaluation in intermittent long-term users with cardiovascular risk factors.
3-Patients should be informed of the possibility of developing medication overuse headaches.
4-This drug may impair judgment, thinking, or motor skills; have patient avoid driving or operating machinery until adverse effects are determined.