Emgality vs. Topamax

See how Emgality and Topamax compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Emgality is a once-monthly injection that targets CGRP to prevent migraine, while Topamax is a daily anticonvulsant pill used for migraine prevention and epilepsy.

  • Emgality is the only FDA-approved drug specifically for preventing episodic cluster headache attacks, a use Topamax does not have.

  • Topamax is available as a low-cost generic, while Emgality is a newer biologic that typically costs several hundred dollars more per month without insurance.

Emgality vs. Topamax Drug Summary

Emgality

Emgality (galcanezumab-gnlm) is a calcitonin gene-related peptide (CGRP) antagonist used to prevent migraine attacks and to treat episodic cluster headache in adults. It's given as a self-administered subcutaneous injection once a month, using a prefilled pen or syringe.

Topamax

Topamax (topiramate) is an anticonvulsant medication approved to prevent migraine in adults and adolescents 12 and older, and to treat certain seizure types in epilepsy. It's taken as an oral tablet twice a day, after a several-week dose increase to reach the maintenance level.

Emgality vs. Topamax Side Effects

Emgality

Most common
Injection site reactions (up to 18%)
Injection site pain (10.1% to 11.6%)
Constipation (1.0% to 1.5%)
Vertigo (0.7% to 1.2%)

Topamax

Most common
Paresthesia (up to 51%)
Fatigue (up to 15%)
Anorexia (up to 15%)
Nausea (up to 13%)

Emgality vs. Topamax Dosage

Emgality

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 240 mg Day 1
Maximum dose 300 mg once monthly If needed
Dose changes 2 increases As tolerated

Topamax

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 25 mg/day Week 1
Maximum dose Up to 200 mg/day If needed
Dose changes 5 increases Every week

Emgality vs. Topamax Indications

Emgality

Emgality is FDA-approved to reduce how often migraine attacks happen in adults and, separately, to treat episodic cluster headache in adults. It was the first medication approved specifically for preventing episodic cluster headache attacks. It is not approved for children or for stopping a migraine once it has started.

  • Preventive treatment of migraine in adults

  • Treatment of episodic cluster headache in adults

  • Not approved for children under 18

  • Not approved for acute migraine treatment

Topamax

Topamax is FDA-approved to prevent migraine headaches in adults and adolescents age 12 and up. It's also approved to treat certain seizure types in epilepsy, as monotherapy and as add-on therapy. Some clinicians prescribe it off-label for weight management or mood disorders, uses the FDA has not reviewed for that purpose.

  • Migraine prevention in adults and adolescents 12+

  • Monotherapy or add-on therapy for certain seizures

  • Seizures associated with Lennox-Gastaut syndrome

  • Off-label: weight loss or bipolar disorder (not FDA-approved)

Emgality vs. Topamax Pros and Cons

Emgality

Emgality's once-monthly injection and targeted mechanism make it a newer option for people who haven't done well on oral preventives. It carries no boxed warning, but as a specialty biologic it often needs prior authorization and costs considerably more than older generic pills like topiramate.

Pros

  • Only one injection needed per month

  • Only FDA-approved drug shown to reduce episodic cluster headache attacks

  • Not linked to cognitive side effects like memory or word-finding problems

  • No warning for birth defects

Cons

  • Typically costs $650 to $900 per month without insurance, much more than generic topiramate

  • Can cause injection site reactions in up to 18% of patients

  • May worsen or trigger Raynaud's phenomenon

  • Often needs prior authorization from insurers

Topamax

Topamax has decades of use behind it and is widely available as an inexpensive generic tablet. Its trade-off is a multi-week titration, a high rate of tingling sensations, and warnings around cognitive slowing and birth defects that require monitoring.

Pros

  • Available as a generic for roughly $20 to $100 per month without insurance, far cheaper than Emgality

  • Oral tablet, no injections needed

  • Also treats epilepsy, useful if a patient has both conditions

  • Decades of real-world prescribing experience

Cons

  • Requires twice-daily dosing with a multi-week dose increase

  • Paresthesia (tingling) affects up to half of patients

  • Carries warnings for cognitive slowing and kidney stones

  • Carries a class warning for increased suicidal thoughts

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