Pantothenate Kinase-Associated Neurodegeneration (PKAN) Medication

Updated: Dec 07, 2016
  • Author: Philip A Hanna, MD; Chief Editor: Selim R Benbadis, MD  more...
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Medication

Medication Summary

As previously mentioned, dopaminergic agents, such as levodopa and bromocriptine, can produce modest improvements in dystonia. If dopaminergic agents are not effective against dystonia, anticholinergics can be used, but they offer only transient relief. Botulinum toxin injections also can improve dystonic muscles.

Agents used to relieve rigidity and spasticity may prove effective against dysarthria, while methscopolamine bromide can deter excessive drooling.

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Antiparkinson Agents, Dopamine Agonists

Class Summary

These agents reduce morbidity associated with dopamine deficiency.

Levodopa/carbidopa (Sinemet, Sinemet CR, Parcopa)

Carbidopa (a decarboxylase inhibitor) is administered with levodopa to prevent the breakdown of levodopa and increase levodopa's bioavailability. Thus, carbidopa decreases the need for large doses of levodopa to achieve adequate brain dopamine levels. The levodopa/carbidopa combination is often used when symptom control with selegiline alone is insufficient. The CR levodopa/carbidopa formulation can help to prevent the on/off phenomenon in some patients.

The Sinemet tablet is available in a 4:1 ratio (Sinemet 100/25) and a 10:1 ratio (Sinemet 100/10 and 250/25) of levodopa to carbidopa. The Sinemet CR tablet contains a 4:1 ratio of levodopa to carbidopa (100/25 or 200/50); the daily dosage of Sinemet CR must be determined by careful titration.

Bromocriptine (Parlodel, Cycloset)

Bromocriptine is a semisynthetic ergot alkaloid derivative. It is a strong dopamine D2-receptor agonist and a partial dopamine D1-receptor agonist. Bromocriptine may relieve akinesia, rigidity, and tremor associated with Parkinson disease. It stimulates dopamine receptors in the corpus striatum. It is, however, less effective than other dopamine agonists. It can be used as an adjunct to levodopa/carbidopa.

Approximately 28% of the drug is absorbed from the gastrointestinal (GI) tract and metabolized in the liver. The approximate elimination half-life is 50 hours, with 85% of bromocriptine excreted in feces and 3-6% eliminated in urine. The drug is initiated at a low dose with slow titration; increase in the dose every 2 weeks. If severe adverse reactions occur, the dose is reduced in 2.5-mg decrements.

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Antiparkinson Agents, Anticholinergics

Class Summary

These agents are thought to act centrally by suppressing the conduction in the vestibular cerebellar pathways. They may have an inhibitory effect on the parasympathetic nervous system.

Trihexyphenidyl

This is a centrally acting anticholinergic agent that tends to diminish the muscle spasms.

Benztropine (Cogentin)

By blocking the striatal cholinergic receptors, benztropine may help in balancing the cholinergic and the dopaminergic activity in the striatum.

Scopolamine (Transderm Scop Patch, Scopace)

Scopolamine blocks the action of acetylcholine at parasympathetic sites in smooth muscle, secretory glands, and the central nervous system (CNS). It antagonizes the action of histamine and serotonin.

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Benzodiazepines

Class Summary

By binding to the specific receptor sites, these agents appear to potentiate the effects of gamma-aminobutyric acid (GABA) and facilitate inhibitory GABA neurotransmission and other inhibitory transmitters.

Clonazepam (Klonopin)

Clonazepam suppresses the muscle contractions by facilitating inhibitory GABA neurotransmission and other inhibitory transmitters.

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Neuromuscular Blocker Agents, Botulinum Toxins

Class Summary

These agents produce symptomatic improvement in muscle strength by relieving spasticity and autonomic symptoms, or both in some patients.

Botulinum toxin type A (BOTOX)

This agent binds to the receptor sites on motor nerve terminals and inhibits the release of acetylcholine, which, in turn, inhibits the transmission of impulses at the neuromuscular junction.

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