Generic Name: Rizatriptan
Therapeutic Class: 5-HT1B/1D Receptor Agonist (Triptan) / Anti-migraine
Indications
Rizatriptan is a selective serotonin (5-HT1) receptor agonist used for the acute treatment of migraine:
- Acute Migraine: Specifically indicated for the acute treatment of migraine attacks with or without aura in adults and pediatric patients (6 to 17 years of age).
- Fast-Onset Relief: Preferred for patients who require rapid relief, as it has one of the fastest clinical onset times among oral triptans.
- Orally Disintegrating Needs: The ODT (Orally Disintegrating Tablet) form is ideal for patients who experience migraine-associated nausea or have difficulty swallowing tablets with water.
Dosage & Administration
Rizatriptan can be administered as conventional tablets or orally disintegrating tablets. It should be taken at the first sign of a migraine headache.
- Adults (18 years and older): The standard dose is 5 mg or 10 mg. A 10 mg dose is generally more effective but may increase the risk of side effects.
- Repeat Dosing: If the headache returns, a second dose may be taken at least 2 hours after the first dose.
- Maximum Adult Dose: Do not exceed 30 mg within a 24-hour period.
- Pediatric Patients (6-17 years): Dosage is based on weight. For patients <40 kg, a single 5 mg dose is used. For patients ≥40 kg, a single 10 mg dose is used. Safety of a second dose in 24 hours for children has not been established.
- Propranolol Interaction: Patients taking Propranolol should only use the 5 mg dose of Rizatriptan, up to a maximum of 15 mg per day.
Description & Pharmacokinetics
Rizatriptan benzoate is a selective agonist for the 5-HT1B and 5-HT1D receptors.
Its therapeutic effect is attributed to two main mechanisms: the constriction of dilated intracranial extracerebral blood vessels and the inhibition of neuropeptide release, which reduces inflammation of the sensory trigeminal nerves.
Pharmacokinetics: Rizatriptan is completely absorbed following oral administration. Its bioavailability is approximately 45%. The peak plasma concentration ($C_{max}$) is reached in approximately 1 hour for conventional tablets and 1.3 hours for ODT. It is minimally bound to plasma proteins (14%). Metabolism occurs primarily via oxidative deamination by Monoamine Oxidase-A (MAO-A). The elimination half-life is short, averaging 2–3 hours.
Pharmacokinetics: Rizatriptan is completely absorbed following oral administration. Its bioavailability is approximately 45%. The peak plasma concentration ($C_{max}$) is reached in approximately 1 hour for conventional tablets and 1.3 hours for ODT. It is minimally bound to plasma proteins (14%). Metabolism occurs primarily via oxidative deamination by Monoamine Oxidase-A (MAO-A). The elimination half-life is short, averaging 2–3 hours.
Extra Important Information: Usage Insights
- ODT Administration: Orally disintegrating tablets should be placed on the tongue, allowed to dissolve, and swallowed with saliva. No water is required.
- Effect of Food: While it can be taken with or without food, food may delay the time to peak concentration by about an hour, potentially slowing the onset of relief.
- Non-Prophylactic: It must not be used for the prevention of migraines or for the treatment of hemiplegic or basilar migraines.
Side Effects
Common adverse reactions observed in clinical trials include:
- Central Nervous System: Dizziness, somnolence (sleepiness), and paresthesia (tingling/numbness).
- Gastrointestinal: Nausea, dry mouth, and diarrhea.
- General: Fatigue, chest/jaw/neck tightness, and flushing.
- Rare: Hypersensitivity reactions, including angioedema or wheezing.
Pregnancy & Lactation
- Pregnancy: Category C. There are no adequate and well-controlled studies in pregnant women. Rizatriptan should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
- Lactation: It is not known whether Rizatriptan is excreted in human milk. However, it is excreted in the milk of lactating rats. Caution should be exercised when administered to a nursing woman.
Precautions & Interactions
- MAO Inhibitors: Rizatriptan is contraindicated in patients receiving MAO-A inhibitors or within 2 weeks of discontinuing them.
- Cardiovascular: Contraindicated in patients with history of Myocardial Infarction (MI), Ischemic Heart Disease, Stroke/TIA, or Peripheral Vascular Disease.
- Propranolol: Propranolol increases Rizatriptan plasma levels by about 70%. Dosage must be limited to 5 mg.
- Serotonin Syndrome: Risk increases when combined with SSRIs (e.g., Fluoxetine) or SNRIs (e.g., Duloxetine).
Storage
Store at room temperature between 20°C to 25°C. Keep ODT formulations in their original aluminum pouches until ready for use to protect from moisture. Keep out of reach of children.
.png)
