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What is the difference between Ruzurgi and Firdapse?

They both contain amifampridine, and they are both used to treat Lambert-Eaton myasthenic syndrome. What's the difference?

Medically reviewed by Drugs.com. Last updated on May 23, 2019.

Official Answer

by Drugs.com

Firdapse (amifampridine phosphate) and Ruzurgi (amifampridine) are both used to treat Lambert-Eaton myasthenic syndrome (LEMS). Firdapse is approved to treat LEMS in adults, and Ruzurgi is approved to treat LEMS in pediatric patients. Firdapse contains amifampridine as the phosphate salt, which is more stable than the base drug contained in Ruzurgi, and therefore does not require refrigeration.

Ruzurgi is also expected to be priced more competitively than Firdapse, which when first approved carried a price tag of $375,000 per year, causing outrage among LEMS patients who had previously been able to access amifampridine for free through an FDA compassionate use program.

Ruzurgi Firdapse
Generic Name amifampridine amifampridine phosphate
Date of FDA Approval May 6, 2019 November 28, 2018
Company Jacobus Pharmaceutical Company Inc. Catalyst Pharmaceuticals, Inc.
Indication LEMS in pediatric patients 6 to less than 17 years of age LEMS in adults
How Supplied Tablets 10 mg (functionally scored) Tablets 10 mg (functionally scored)
Administration Ruzurgi can be taken without regard to food. Firdapse can be taken without regard to food.
Dosing Tablets may be halved, or prepared as a 1 mg/mL suspension for patients who require a dose less than 5 mg. Tablets may be halved
Storage and Handling Prior to Dispensing: Store Ruzurgi tablets in a refrigerator between 2°C to 8°C (36°F to 46°F). Keep container tightly closed with desiccant canister inside after opening. Protect from moisture and light.

After Dispensing: Store Ruzurgi tablets at 20°C to 25°C (68°F to 77°F) for up to 3 months; excursions permitted between 15°C to 30°C (59°F to 86°F)

Store Firdapse tablets at 20°C to 25°C (68°F to 77°F) with excursions permitted from 15°C to 30°C (59°F to 86°F)

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