Description and Brand Names

Drug information provided by: Merative, Micromedex®

US Brand Name

  1. Firdapse
  2. Ruzurgi

Descriptions


Amifampridine is used to treat Lambert-Eaton myasthenic syndrome (LEMS), a rare autoimmune disease, wherein the immune system attacks the connection between the nerve and muscle (neuromuscular junction) and blocks the ability of the nerve cells to send signals to the muscle cells, leading to muscle weakness of the arms or legs.

This medicine is available only with your doctor's prescription.

This product is available in the following dosage forms:

  • Tablet

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of amifampridine in children younger than 6 years of age. Safety and efficacy have not been established.

Geriatric

No information is available on the relationship of age to the effects of Ruzurgi® in geriatric patients.

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of Firdapse® in the elderly. However, elderly patients are more likely to have age-related liver, kidney, or heart problems, which may require caution and an adjustment in the dose for patients receiving this medicine.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Acetophenazine
  • Aclidinium
  • Acrivastine
  • Alcaftadine
  • Alfentanil
  • Amantadine
  • Ambenonium
  • Amdinocillin
  • Amdinocillin Pivoxil
  • Amineptine
  • Aminophylline
  • Amitriptylinoxide
  • Amoxapine
  • Amphetamine
  • Ampicillin
  • Anisotropine
  • Antazoline
  • Atropine
  • Azatadine
  • Azelastine
  • Azlocillin
  • Bacampicillin
  • Baclofen
  • Belladonna Alkaloids
  • Benperidol
  • Benzhydrocodone
  • Benzphetamine
  • Bepotastine
  • Bornaprine
  • Bromodiphenhydramine
  • Bromperidol
  • Brompheniramine
  • Buclizine
  • Bupivacaine
  • Butorphanol
  • Butriptyline
  • Butylscopolamine
  • Carbenicillin
  • Carbinoxamine
  • Chlorambucil
  • Chlorotrianisene
  • Chlorpheniramine
  • Chlorphenoxamine
  • Cimetropium
  • Cinnarizine
  • Clemastine
  • Clemizole
  • Clidinium
  • Cloxacillin
  • Cocaine
  • Codeine
  • Conjugated Estrogens
  • Cyclacillin
  • Cyclizine
  • Cyclopentolate
  • Cyclosporine
  • Cyproheptadine
  • Darifenacin
  • Demecarium
  • Dexbrompheniramine
  • Dexchlorpheniramine
  • Dextroamphetamine
  • Dibenzepin
  • Dicloxacillin
  • Dicyclomine
  • Dienestrol
  • Diethylstilbestrol
  • Difenoxin
  • Dihydrocodeine
  • Dimenhydrinate
  • Dimethindene
  • Diphenhydramine
  • Diphenylpyraline
  • Distigmine
  • Dixyrazine
  • Donepezil
  • Dothiepin
  • Doxylamine
  • Echothiophate
  • Edrophonium
  • Emedastine
  • Enflurane
  • Epinastine
  • Esterified Estrogens
  • Estradiol
  • Estramustine
  • Estriol
  • Estrone
  • Estropipate
  • Ethinyl Estradiol
  • Ethopropazine
  • Fentanyl
  • Fesoterodine
  • Flavoxate
  • Floxacillin
  • Flunarizine
  • Glycopyrrolate
  • Guanidine
  • Hetacillin
  • Homatropine
  • Hydrocodone
  • Hydromorphone
  • Hydroxyamphetamine
  • Hyoscyamine
  • Indalpine
  • Iprindole
  • Isoflurophate
  • Isoniazid
  • Isopropamide
  • Ketamine
  • Ketotifen
  • Levocabastine
  • Levomilnacipran
  • Levorphanol
  • Lidocaine
  • Lindane
  • Lisdexamfetamine
  • Lithium
  • Lofepramine
  • Loxapine
  • Mebeverine
  • Mebhydrolin
  • Meclizine
  • Mefenamic Acid
  • Melitracen
  • Melperone
  • Mepenzolate
  • Meperidine
  • Mestranol
  • Methamphetamine
  • Methantheline
  • Methdilazine
  • Methicillin
  • Methixene
  • Methotrimeprazine
  • Methylphenidate
  • Metopimazine
  • Mezlocillin
  • Milnacipran
  • Morphine
  • Nalbuphine
  • Nalidixic Acid
  • Neostigmine
  • Niaprazine
  • Nortriptyline
  • Olopatadine
  • Opipramol
  • Orphenadrine
  • Oxacillin
  • Oxatomide
  • Oxycodone
  • Oxymorphone
  • Penicillin G
  • Penicillin V
  • Pentazocine
  • Perazine
  • Periciazine
  • Phenindamine
  • Pheniramine
  • Phenylpropanolamine
  • Phenyltoloxamine
  • Physostigmine
  • Pinaverium
  • Piperacillin
  • Pipotiazine
  • Pirenzepine
  • Pivampicillin
  • Pizotyline
  • Polyestradiol Phosphate
  • Procaine
  • Promazine
  • Promestriene
  • Propantheline
  • Propicillin
  • Propiverine
  • Propizepine
  • Propoxyphene
  • Pyrilamine
  • Quinestrol
  • Remifentanil
  • Rivastigmine
  • Scopolamine
  • Sibutramine
  • Sufentanil
  • Sulbenicillin
  • Sultamicillin
  • Tacrine
  • Tapentadol
  • Temocillin
  • Theophylline
  • Thiethylperazine
  • Thiopropazate
  • Thioproperazine
  • Thonzylamine
  • Tianeptine
  • Tibolone
  • Ticarcillin
  • Timiperone
  • Tiotropium
  • Tramadol
  • Trifluoperazine
  • Triflupromazine
  • Trimeprazine
  • Tripelennamine
  • Triprolidine
  • Tropicamide
  • Trospium
  • Umeclidinium
  • Valethamate

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Kidney disease or
  • Liver disease—Use with caution. The effects may be increased because of the slower removal of the medicine from the body.
  • Seizures, history of—Should not be used in patients with this condition.

Proper Use

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

This medicine comes with a Medication Guide and patient information leaflet. Read and follow these instructions carefully. Ask your doctor if you have any questions.

You may take this medicine with or without food.

The tablets may be divided in half at the score (line at the center) if you need less than a full tablet to get the right dose.

If you or your child are unable to swallow the tablets whole, you may prepare a suspension:

  • Ruzurgi®: Mix 3 tablets with 30 milliliters (mL) of water in a 30-mL container, then shake the mixture well for 30 seconds. You may give the dose using an oral dosing syringe or feeding tube. Shake well before giving each dose.
  • Firdapse®: Mix the tablet with 10 mL of sterile water for each tablet in a 50 to 100 mL container, wait for 5 minutes. Shake well for 30 seconds. You may give the dose using an oral dosing syringe or feeding tube. Shake well before giving each dose.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For Lambert-Eaton myasthenic syndrome:
      • Fidarpse®:
        • Adults and children 6 years of age and older weighing 45 kilograms (kg) or more—Dose is based on body weight and must be determined by your doctor. At first, 15 milligrams (mg) to 30 mg given in 3 to 4 divided doses per day. Your doctor may adjust your dose as needed. However, the dose is usually not more than 80 mg per day.
        • Children 6 years of age and older weighing less than 45 kg—Dose is based on body weight and must be determined by your doctor. At first, 5 mg to 15 mg given in 3 to 4 divided doses per day. Your doctor may adjust your dose as needed. However, the dose is usually not more than 40 mg per day.
        • Children younger than 6 years of age—Use and dose must be determined by your doctor.
      • Ruzurgi®:
        • Children 6 to 16 years of age weighing 45 kilograms (kg) or more—Dose is based on body weight and must be determined by your doctor. At first, 15 milligrams (mg) to 30 mg given 2 to 3 divided doses per day. Your doctor may adjust your dose as needed. However, the dose is usually not more than 100 mg per day.
        • Children 6 to 16 years of age weighing less than 45 kg—Dose is based on body weight and must be determined by your doctor. At first, 7.5 mg to 15 mg given 2 to 3 divided doses per day. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg per day.
        • Children younger than 6 years of age—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Store Ruzurgi® tablets at room temperature for up to 3 months.

You may store the mixture in the refrigerator for up to 24 hours. Throw away any unused liquid after 24 hours.

Precautions

It is very important that your doctor check your or your child's progress at regular visits to make sure this medicine is working properly.

This medicine may increase your risk for seizures and should not be given to patients who have had seizures.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and require immediate medical attention. Tell your doctor right away if you have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth after using this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

  1. Arm or leg pain
  2. bladder pain
  3. bloating or swelling of the face, arms, hands, lower legs, or feet
  4. bloody or cloudy urine
  5. blurred vision
  6. burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  7. chest pain or tightness
  8. chills
  9. cough
  10. cough producing mucus
  11. diarrhea
  12. difficult, burning, or painful urination
  13. difficulty breathing or swallowing
  14. dizziness
  15. fever
  16. frequent urge to urinate
  17. general feeling of discomfort or illness
  18. headache
  19. hoarseness
  20. joint pain
  21. loss of appetite
  22. lower back or side pain
  23. muscle pains, spasms, or weakness
  24. nausea
  25. nervousness
  26. pounding in the ears
  27. rapid weight gain
  28. runny nose
  29. shivering
  30. slow or fast heartbeat
  31. sneezing
  32. sore throat
  33. sweating
  34. swollen, painful, or tender lymph glands in the neck, armpit, or groin
  35. trouble sleeping
  36. unusual tiredness or weakness
  37. unusual weight gain or loss
  38. vomiting

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  1. Back pain
  2. blindness
  3. constipation
  4. decreased vision
  5. discouragement
  6. falls
  7. feeling cold
  8. feeling sad or empty
  9. heartburn
  10. irritability
  11. lack or loss of strength
  12. loss of interest or pleasure
  13. pale skin
  14. stomach pain
  15. trouble concentrating
  16. trouble breathing
  17. unusual bleeding or bruising

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Portions of this document last updated: Feb. 01, 2024

Original article: https://www.mayoclinic.org/drugs-supplements/amifampridine-oral-route/description/drg-20463409