Amantadine

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Immediate-release amantadine is a mild agent that is used in early and advanced PD to help tremor. In recent years, amantadine has also been found useful in reducing dyskinesias that occur with dopamine medication. In 2017, an extended-release form of amantadine (Gocovri) was the first drug approved by the FDA specifically to treat dyskinesia in Parkinson's.

Forms of Amantadine

Amantadine (Symmetrel)

Available Doses: 100 mg capsules; 100 mg tablets, 50mg/5ml syrup
Typical Treatment Regimen: 100 mg 2–3 times/day
Common Side Effects: Dizziness, hallucination, paranoia, nausea, confusion, leg discoloration, dizziness/low blood pressure from seated to standing, dry mouth, constipation, urinary retention, and potential effect of arrythmias
Indications for Usage: Monotherapy for slowness, stiffness, and tremor; combination therapy with levodopa for levodopa-induced dyskinesia

Amantadine ER capsules (Gocovri)

Available Doses: 68.5 mg, 137 mg
Typical Treatment Regimen: 137 – 274mg once/day at bedtime
Common Side Effects: Dizziness, hallucination, paranoia, nausea, confusion, leg discoloration, dizziness/low blood pressure from seated to standing, dry mouth, constipation, urinary retention, and potential effect of arrythmias
Indications for Usage: Dyskinesia in patients with levodopa therapy; “Off” episodes in Parkinson disease

Amantadine ER tablets (Osmolex ER)

Available Doses: 129 mg, 193 mg, 258 mg
Typical Treatment Regimen: 129 – 322mg once/day (upon waking
Common Side Effects: Dizziness, hallucination, paranoia, nausea, confusion, leg discoloration, dizziness/low blood pressure from seated to standing, dry mouth, constipation, urinary retention, and potential effect of arrythmias
Indications for Usage: Dyskinesia in patients with levodopa therapy; “Off” episodes in Parkinson disease

Common Side Effects

  • Dizziness
  • Low Blood Pressure
  • Nausea
  • Insomnia
  • Confusion
  • Paranoia
  • Hallucinations
  • Leg discoloration

Uncommon Side Effects

  • Urinary retention
  • Livedo reticularis: a lacey, purplish discoloration of the skin on the legs with some leg swelling. Occurs in less than 1 percent of people with PD who take this medication.

Quick Facts

  • Amantadine was initially developed as an antiviral medication to treat influenza in the 1960s; later it was realized that it can be used as a treatment for PD, and this use was confirmed in clinical trials.
  • Immediate Release Amantadine can be used as a monotherapy for Parkinson’s motor symptoms or as combination therapy with levodopa for levodopa-induced dyskinesia.
  • Extended-release Amantadine is used as combination therapy with levodopa for levodopa for levodopa-induced dyskinesia and “Off” episodes.
  • Immediate-release amantadine is most commonly available in 100 mg capsules, although liquid and tablet forms can also be obtained. Most people take multiple doses per day.
  • Extended-release amantadine is a once per day treatment option. People who are doing well on multiple doses per day of generic amantadine may not benefit from switching to one-a-day Gocovri or Osmolex ER, but people who experience side effects from amantadine now have another option. 
  • No trial has been done comparing immediate- and extended-release amantadine, but many trials show that amantadine in any formulation can be effective at suppressing dyskinesia.

Disclaimers:
* Please note that the side effects listed in the tables that accompany each class of medication are the most commonly experienced. Not all individuals will experience such side effects. For many people who do experience side effects, they can often be effectively limited or eliminated with careful adjustments to dosage or the timing of the individual doses.

Speak to the treating physician immediately if any side effects are experienced. For a complete description of each drug and its possible side effects, please request a “package insert” from your pharmacist for each drug used. It is recommended that all prescriptions be filled at the same pharmacy to avoid interactions between medications. Interactions can be dangerous and even life-threatening, so make sure the pharmacist knows of all medications and supplements being taken, including over-the-counter medications and supplements.

Caution: PD medications may have interactions with certain foods, other medications, vitamins, herbal supplements, over the counter cold pills and other remedies. Anyone taking a PD medication should talk to their doctor and pharmacist about potential drug interactions.

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