Firazyr
Firazyr
Generic Name
Firazyr
Mechanism
Firazyr blocks peripheral vasodilation by constricting cranial and meningeal blood vessels and inhibits the release of pro‑inflammatory neuropeptides (e.g., CGRP, PACAP).
• Acts on 5‑HT1B receptors → vasoconstriction.
• Acts on 5‑HT1D receptors → reduces trigeminal nerve neurotransmission.
---
Pharmacokinetics
Firazyr is absorbed rapidly:
• Oral: Cmax ~35 min, bioavailability 40 %.
• SC: Cmax ~5 min, bioavailability 100 %.
• Half‑life: 2–3 h (oral) / 1.5–2 h (SC).
• Metabolism: N‑acetylation, reduction, and hydrolysis; renal and hepatic routes.
• Elimination: ~70 % renal, 30 % via feces.
• No significant drug–drug interactions except with serotonergic agents (serotonin syndrome risk).
---
Indications
Firazyr is approved for:
• Acute migraine attacks (with or without aura) in adults ≥12 yrs.
• Migraine associated with vestibular or visual symptoms.
• Patients when other therapies (NSAIDs, acetaminophen) fail or are contraindicated.
---
Contraindications
Contraindications
• Uncontrolled hypertension or recent myocardial infarction.
• Known or suspected cerebrovascular accident within past 6 mo.
• History of ischemic heart disease.
• Pregnancy (Category X) & lactation.
Warnings
• Serotonin syndrome: avoid when concomitant with MAO inhibitors, SSRIs, SNRIs, or other serotonergic drugs.
• Cardiovascular: transient chest pain, ischemia, or dysrhythmias may occur.
• Migraine with aura: increase cardiovascular risk; use with caution.
---
Dosing
| Form | Dose | Frequency | Comments |
| Oral | 100 mg single tablet | On onset of attack | May repeat after >2 h, max 200 mg per attack |
| SC | 50 mg single injection | On onset | Subcutaneous offers faster relief (t½ ~1.5 h) |
| Pediatric (12–15 yrs) | 0.4 mg/kg (max 100 mg) | As above | Monitor growth & development safety data |
*Take with water; do not chew or crush.*
--
•
Adverse Effects
Common (≥5 %)
• Flushing, warmth, tingling.
• Dizziness, headache, palpitations.
• Nausea, abdominal pain.
• Fatigue.
Serious (≤1 %)
• Chest pain or angina.
• Severe headache, transient ischemic attack (TIA).
• Serotonin syndrome: agitation, confusion, hyperthermia.
• Severe orthostatic hypotension (rare).
---
Monitoring
- Cardiovascular: vital signs (BP, HR) before and 30 min post‑dose; ECG if chest pain.
- Renal/Hepatic: baseline LFTs & renal function for chronic users; adjust dose if severe impairment.
- Pregnancy: avoid; if inadvertent exposure, discuss risk/benefit.
- Drug interactions: review serotonergic medication history.
---
Clinical Pearls
- Rapid Onset: SC route halves the onset time—ideal for patients with high headache-aggressive migraine.
- Timing Matters: complete pain relief is most likely when taken early (within 10 min of onset).
- Avoid Over‑Dose: limit to 200 mg per 24‑h period; repeated dosing increases cardiovascular risk.
- Seizure Precaution: sumatriptan is contraindicated in patients with seizure disorders due to potential seizure precipitant.
- Pregnancy & Lactation: no FDA‑approved use; if exposure unavoidable, discontinue breastfeeding.
- Drug‑Drug Alerts: combine sumatriptan with SSRIs/MAOIs cautiously; act as a red flag for serotonin syndrome.
- Use in Chronic Migraine: consider prophylaxis with topiramate or propranolol if frequent attacks despite acute therapy.
--
• Firazyr provides a fast‑acting, effective option for acute migraine management—particularly in patients who need rapid relief and tolerate serotonergic stimulation.