Rizatriptan-Sumatriptan Dose Equivalency
Rizatriptan 10 mg is approximately equivalent to sumatriptan 100 mg, while rizatriptan 5 mg is approximately equivalent to sumatriptan 50 mg, though rizatriptan demonstrates superior efficacy and faster onset at these equivalent doses. 1, 2
Standard Dose Comparisons
The direct comparative trials establish the following dose relationships:
Rizatriptan 10 mg vs. Sumatriptan 100 mg: These are the standard maximum single doses for each medication, with rizatriptan 10 mg showing superior 2-hour headache relief rates (consistently higher at all time points up to 2 hours, with 37% vs 28% at 1 hour, P=0.010) and earlier time to pain relief (hazard ratio 1.21, P=0.032) 2
Rizatriptan 5 mg vs. Sumatriptan 50 mg: These represent the lower dose comparisons, with rizatriptan 5 mg providing faster relief and greater symptom resolution than sumatriptan 50 mg 3
Rizatriptan 5 mg vs. Sumatriptan 25 mg: This comparison also favors rizatriptan for speed and efficacy 3
Pharmacokinetic Advantages of Rizatriptan
Rizatriptan's superior performance at equivalent doses stems from pharmacokinetic differences:
Faster absorption: Rizatriptan reaches maximum plasma concentration (Tmax) at 1 hour versus 2-2.5 hours for sumatriptan 4
Higher bioavailability: Rizatriptan has 45% bioavailability compared to only 15% for oral sumatriptan 4
These pharmacological advantages translate into faster onset of action and better overall response rates 4
Clinical Efficacy Comparisons
When comparing rizatriptan 10 mg to sumatriptan 100 mg specifically:
Pain-free at 2 hours: 40% for rizatriptan 10 mg vs. 33% for sumatriptan 100 mg 4
Complete symptom freedom at 2 hours: Rizatriptan 10 mg superior 4
Relief of nausea: Rizatriptan 10 mg significantly better (P=0.010) 2
Functional disability reduction: Rizatriptan 10 mg superior (P=0.015) 2
Patient satisfaction: Higher with rizatriptan 10 mg 4
Safety Profile Comparison
Both medications share similar adverse effect profiles, with dizziness, drowsiness, and asthenia/fatigue being most common (affecting <10% of patients) 4
Fewer drug-related adverse events were reported with rizatriptan 10 mg (33%) compared to sumatriptan 100 mg (41%, P=0.014) 2
Chest pain occurred in 1-3% of rizatriptan recipients versus 3-6% with sumatriptan 5
Important Prescribing Considerations
24-hour separation rule: Both medications cannot be used within 24 hours of each other, as they are both triptans 6, 7
Maximum daily doses: Rizatriptan maximum is 30 mg per 24 hours (three 10 mg doses), while sumatriptan oral maximum is 200 mg per 24 hours 6
Trial period: Patients must try either medication for 2-3 separate headache episodes before determining effectiveness 6
Medication overuse threshold: Limit use to no more than 10 days per month to prevent medication overuse headache 6
Common Pitfall to Avoid
Do not increase triptan dose or frequency if initial response is inadequate; instead, add an NSAID (naproxen, ibuprofen, or diclofenac) or acetaminophen, as combination therapy is more effective than dose escalation 6