Striatonigral Degeneration Medication

Updated: Nov 13, 2019
  • Author: Ahmad El Kouzi, MD; Chief Editor: Selim R Benbadis, MD  more...
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Medication

Medication Summary

The drugs in the tables below are specific to the treatment of parkinsonism and postural hypotension associated with multiple system atrophy with predominantly parkinsonian features (MSA-P). As previously mentioned, in patients with multiple system atrophy, the response to antiparkinsonian medications is suboptimal at best. Because better options are not available, however, these agents remain the treatment of choice for the disease.

Adjunct medications

Anticholinergic medications, such as oxybutynin, are sometimes used for incontinence but often lead to subsequent retention. Although sildenafil has been used for treatment of erectile dysfunction, it is generally not recommended, due to its high potential to provoke or exacerbate hypotension. The use of a fiber supplement or another bowel regimen may be necessary for constipation.

A selective serotonin reuptake inhibitor (SSRI) or similar drug may be required for the treatment of depression often associated with all subtypes of multiple system atrophy. For patients who suffer from REM sleep behavioral disorder, clonazepam may be beneficial. Botulinum toxin (BOTOX®) injection to the vocal cords has been used for the treatment of stridor.

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Antiparkinson Agents, Dopamine Agonists

Class Summary

Dopaminergic drugs can exacerbate orthostatic hypotension. They must be initiated at low doses and cautiously titrated up.

Levodopa-carbidopa (Sinemet, Parcopa)

Levodopa is a dopamine precursor used to increase central nervous system (CNS) dopamine concentration, as it is not possible for dopamine to cross the blood-brain barrier. Carbidopa is a peripheral dopa decarboxylase inhibitor that prevents premature conversion of levodopa to dopamine in the tissues prior to entering the CNS. It increases the efficiency of levodopa therapy, allows for lower dosages, and also decreases the side effects associated with peripheral conversion.

Standard release forms of levodopa-carbidopa are available in 25/100-, 10/100-, and 25/250-mg tablets. Controlled-release preparations are available in 50/200 mg and 25/100 mg.

Pramipexole (Mirapex)

Pramipexole is a nonergot dopamine agonist that is used with or without concomitant levodopa therapy. It binds D2 and D3 dopamine receptors. Due to pramipexole's high specificity for D3 receptors (relative to other dopamine agonists), it may cause less orthostatic hypotension. It has no significant effect on other adrenergic or serotonergic receptors. The drug's absolute bioavailability is greater than 90%. Its peak serum concentration is reached in approximately 2 hours and its half-life is approximately 8 hours.

There are no known metabolites; roughly 90% of this drug is renally excreted in its unchanged form. Tablets are available in 0.125-, 0.25-, 0.5-, 0.75-, 1-, and 1.5-mg forms.

Ropinirole (Requip)

Ropinirole is a nonergot dopamine agonist that is used with or without concomitant levodopa therapy. It binds to D2 and D3 receptors but has a greater affinity for D3. Ropinirole's bioavailability is 55%, its peak plasma concentration is reached in 1-2 hours, and its half-life is approximately 6 hours. Ropinirole is extensively metabolized by the liver via P450 CYP1A2. Less than 10% of the drug is renally excreted; no dosage change is required in mild to moderate renal insufficiency. If ropinirole is used as adjunct therapy, it may be possible to titrate levodopa dosage slowly downward.

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Corticosteroids

Class Summary

These are used to treat orthostatic hypotension that is refractory to nonpharmacologic recommendations.

Fludrocortisone

Fludrocortisone is a synthetic steroid with predominantly mineralocorticoid activity. It acts on renal distal tubules to enhance the reabsorption of sodium and increase the urinary excretion of potassium. The net effect is an increase in plasma volume and an elevation of blood pressure. The drug's metabolism is primarily hepatic.

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Alpha1 Agonists

Class Summary

These drugs are used to treat orthostatic hypotension that is refractory to nonpharmacologic recommendations.

Midodrine

Midodrine is a selective alpha1-adrenergic agonist used for the treatment of hypotension.

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Benzodiazepines

Class Summary

These drugs are used for REM sleep behavior disorder (RBD).

Clonazepam (Klonopin)

Clonazepam is a benzodiazepine which binds to gamma aminobutyric acid (GABA)-A receptors in the CNS. It may help regulate sleep disorders.

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