Usage
- Rizatriptan is prescribed for the acute treatment of migraine attacks with or without aura. It is not intended for preventative therapy of migraine or for the treatment of cluster headaches.
- Pharmacological Classification: Rizatriptan is a selective 5-hydroxytryptamine receptor agonist, specifically a 5-HT1B/1D agonist, commonly referred to as a “triptan.”
- Mechanism of Action: Rizatriptan binds to 5-HT1B/1D receptors, primarily on intracranial blood vessels and sensory nerves associated with the trigeminal vascular system. This binding leads to vasoconstriction of cranial blood vessels, reducing inflammation and inhibiting the release of neuropeptides involved in pain transmission, thereby relieving migraine symptoms.
Alternate Names
- International Nonproprietary Name (INN): Rizatriptan
- Brand Names: Maxalt, Maxalt-MLT, RizaFilm
How It Works
- Pharmacodynamics: Rizatriptan primarily exerts its therapeutic effect through vasoconstriction of cranial blood vessels and inhibition of neuropeptide release, effectively aborting a migraine attack.
- Pharmacokinetics:
- Absorption: Rizatriptan is rapidly absorbed after oral administration, with an absolute bioavailability of approximately 40-45% due to first-pass metabolism.
- Metabolism: Rizatriptan is primarily metabolized by monoamine oxidase-A (MAO-A) to an inactive indole acetic acid metabolite.
- Elimination: Rizatriptan and its metabolites are predominantly eliminated through renal excretion, with a half-life of about 2-3 hours.
- Mode of Action: Rizatriptan selectively binds to 5-HT1B and 5-HT1D receptors. 5-HT1B receptor activation leads to cranial vessel constriction, while 5-HT1D receptor stimulation inhibits the release of pro-inflammatory neuropeptides, such as calcitonin gene-related peptide (CGRP), substance P, and neurokinin A.
- Elimination Pathways: Primarily renal excretion.
Dosage
Standard Dosage
Adults:
- Initial dose: 5 mg or 10 mg orally. The 10 mg dose may offer better efficacy but carries a slightly higher risk of side effects.
- Redosing: If migraine recurs, a second dose may be administered 2 hours after the first.
- Maximum daily dose: 30 mg in any 24-hour period.
- Maximum monthly usage: No more than 10 days in any 30-day period to minimize medication overuse headache.
Children (6-17 years):
- Weight < 40 kg (88 lbs): 5 mg single dose.
- Weight ≥ 40 kg (88 lbs): 10 mg single dose.
- Maximum: One dose in any 24-hour period.
Special Cases:
- Elderly Patients: No specific dosage adjustments are typically required. Monitor for adverse events.
- Patients with Renal Impairment: Dosage adjustment is necessary in severe renal impairment (creatinine clearance <10 mL/min). A 5 mg dose is recommended.
- Patients with Hepatic Dysfunction: No specific dosage adjustments are required in mild to moderate hepatic dysfunction. In severe hepatic impairment, the use of Rizatriptan is contraindicated.
- Patients with Comorbid Conditions:
- Cardiovascular Disease: Use with caution in patients with cardiovascular risk factors. Cardiac evaluation is recommended prior to initiation of therapy in such cases.
- Concurrent use of Propranolol: Reduce rizatriptan dose to 5 mg with a maximum of 15 mg per 24-hour period for adults. For pediatric patients ≥ 40 kg, a single 5 mg dose is recommended (maximum 5 mg in a 24-hour period). Concomitant use is contraindicated in pediatric patients <40 kg.
Clinical Use Cases
Rizatriptan is specifically indicated for the acute treatment of migraine attacks. It is not recommended for other conditions such as:
- Intubation
- Surgical Procedures
- Mechanical Ventilation
- Intensive Care Unit (ICU) Use
- Emergency Situations (e.g., status epilepticus, cardiac arrest)
Dosage Adjustments
- Renal/Hepatic Dysfunction: As described in the “Special Cases” section.
- Metabolic Disorders/Genetic Polymorphisms: No specific dosage adjustments outlined in the current literature. Monitor carefully.
Side Effects
Common Side Effects:
- Dizziness
- Somnolence
- Fatigue
- Asthenia
- Paresthesia
- Nausea
- Dry mouth
- Flushing
Rare but Serious Side Effects:
- Myocardial infarction
- Stroke
- Arrhythmias
- Coronary vasospasm (Prinzmetal’s angina)
- Cerebrovascular events
- Hypersensitivity reactions (angioedema, anaphylaxis)
- Serotonin syndrome (when combined with serotonergic drugs)
Long-Term Effects:
- Medication overuse headache (if used excessively).
Adverse Drug Reactions (ADR):
- Any sign of cardiac ischemia or cerebrovascular events requires immediate cessation of rizatriptan and urgent medical evaluation. Serotonin syndrome also requires immediate medical intervention.
Contraindications
- Hypersensitivity to rizatriptan
- Ischemic or vasospastic coronary artery disease
- Uncontrolled hypertension
- Peripheral vascular disease (including ischemic bowel disease)
- History of stroke or transient ischemic attack (TIA)
- Basilar or hemiplegic migraine
- Concurrent or recent use (within 24 hours) of ergot-containing medications or other 5-HT1 agonists
- Concurrent use or recent discontinuation (within two weeks) of MAO inhibitors
- Severe hepatic impairment
Drug Interactions
- MAO Inhibitors: Concomitant use is contraindicated due to the risk of serotonin syndrome.
- Ergot-containing drugs: Concurrent use within 24 hours is contraindicated due to additive vasospastic effects.
- Propranolol: Increases rizatriptan plasma levels. Dosage adjustment of rizatriptan is necessary.
- SSRIs, SNRIs, TCAs: Increased risk of serotonin syndrome. Close monitoring for serotonin toxicity is essential.
- CYP450 Interactions: Rizatriptan is primarily metabolized by MAO-A, not CYP450 enzymes, though potential interactions with strong CYP450 inhibitors or inducers may occur.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: B1 (Australian categorization). Data is insufficient to definitively assess the risk of major birth defects and miscarriage. While animal studies have not demonstrated adverse developmental effects, caution is advised.
- Breastfeeding: Rizatriptan is excreted in breast milk. It is recommended to avoid breastfeeding for 24 hours after administration to minimize infant exposure.
Drug Profile Summary
- Mechanism of Action: 5-HT1B/1D receptor agonist, causing cranial vasoconstriction and inhibition of neuropeptide release.
- Side Effects: Dizziness, somnolence, fatigue, paresthesia, nausea. Rarely: myocardial infarction, stroke, arrhythmias.
- Contraindications: Cardiovascular disease, uncontrolled hypertension, cerebrovascular or peripheral vascular disease, recent use of ergot alkaloids or other triptans, MAO inhibitors.
- Drug Interactions: MAO inhibitors, ergot alkaloids, propranolol, SSRIs/SNRIs/TCAs.
- Pregnancy & Breastfeeding: Insufficient data in pregnancy. Avoid breastfeeding for 24 hours after administration.
- Dosage: Adults: 5-10 mg initially, up to 30 mg/day. Children (6-17 years): 5 mg (<40 kg), 10 mg (≥40 kg).
- Monitoring Parameters: Blood pressure, heart rate, neurological status.
Popular Combinations
Rizatriptan is typically used as monotherapy for acute migraine treatment. Combination therapy with NSAIDs or other analgesics may be considered, but caution is advised due to potential additive effects and increased risk of adverse events. Careful evaluation of the patient’s individual situation is necessary.
Precautions
- General Precautions: Assess cardiovascular risk factors before initiating therapy. Rule out other potential causes of headache. Screen for potential drug interactions.
- Specific Populations: See “Dosage - Special Cases” and “Pregnancy and Breastfeeding” sections.
- Lifestyle Considerations: No specific lifestyle restrictions are necessary, but patients should avoid operating machinery or driving until they know how rizatriptan affects them.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Rizatriptan?
A: Adults: 5 mg or 10 mg initially, repeat dose after 2 hours if needed, maximum 30 mg/24 hours. Children (6-17 years): 5 mg (<40 kg), 10 mg (≥40 kg), single dose only.
Q2: How quickly does Rizatriptan work?
A: Onset of pain relief can occur within 30 minutes, with peak effect observed around 2 hours post-dose.
Q3: Can Rizatriptan be used for migraine prevention?
A: No, rizatriptan is indicated only for acute treatment of migraine attacks, not for prophylaxis.
Q4: What are the most common side effects of Rizatriptan?
A: Dizziness, drowsiness, fatigue, paresthesia, nausea, and dry mouth.
Q5: What are the contraindications to using Rizatriptan?
A: Cardiovascular disease, uncontrolled hypertension, peripheral vascular disease, history of stroke or TIA, recent use of ergotamine or other triptans, MAO inhibitor use.
Q6: Can Rizatriptan be taken with propranolol?
A: Yes, but the dose of rizatriptan should be reduced to 5 mg (max 15 mg/24 hours in adults, max 5 mg/24 hours in pediatric patients ≥ 40 kg). Contraindicated in pediatric patients <40 kg taking propranolol.
Q7: Is Rizatriptan safe during pregnancy?
A: Data are insufficient to determine safety in pregnancy. Consult with an obstetrician to assess the risks and benefits.
Q8: Can Rizatriptan be taken while breastfeeding?
A: It is recommended to avoid breastfeeding for 24 hours after taking rizatriptan to minimize infant exposure.
Q9: Can rizatriptan be used for other types of headaches?
A: No, rizatriptan is specifically indicated for migraine headaches. It is not effective for other headache types like tension headaches or cluster headaches.
Q10: What should patients do if they experience chest pain after taking rizatriptan?
A: Chest pain could be a sign of a serious cardiac event. Patients should seek immediate medical attention.
