THERAPEUTICS

Brands

• Requip, Requip XL, Adartrel

Generic?

• Yes

Class

• Antiparkinson agent

Commonly Prescribed for

(FDA approved in bold)

• Parkinson's disease (PD)

• Restless legs syndrome (RLS) (except for Requip XL)

How the Drug Works

• Dopamine agonist, with high affinity for the pre and postsynaptic D2, D3, D4 receptors. The antiparkinson action is likely due to D2 agonism within the caudate-putamen. High affinity to D3 receptors might affect impulse control and dyskinesia. The mechanism of action for RLS is probably related to D2 or D3 receptor agonism

How Long Until It Works

• PD: weeks

• RLS: days to weeks

If It Works

• PD: may require dose adjustments over time or augmentation with other agents. Most PD patients will eventually require carbidopalevodopa to manage their symptoms

• RLS: safe for long-term use with dose adjustments

If It Doesn't Work

• PD: bradykinesia, gait, and tremor should improve. Non-motor symptoms including autonomic symptoms such as postural hypotension, depression, and bladder dysfunction do not improve. If the patient has significantly impaired functioning, add carbidopa-levodopa with or without ropinirole

• RLS: rule out peripheral neuropathy, iron deficiency, thyroid disease. Change to another drug such as a benzodiazepine. Gabapentin enacarbil (not gabapentin) may also be beneficial. In severe cases consider opioids

Best Augmenting Combos for Partial Response or Treatment-Resistance

• For suboptimal effectiveness add carbidopa-levodopa with or without a catechol-O-methyltransferase (COMT) inhibitor. Monoamine oxidase (MAO)-B inhibitors may also be beneficial

• For severe motor fluctuations and/or dyskinesias with good “on” time, functional neurosurgery is an option

• For RLS, can change to a different dopamine agonist (pramipexole, carbidopa-levodopa) or add another drug such as a clonazepam. Gabapentin enacarbil may be beneficial. In severe cases consider opioids

Tests

• None required

ADVERSE EFFECTS (AEs)

How the Drug Causes AEs

• Direct effect on dopamine receptors

Notable AEs

• Nausea/vomiting, dizziness, hallucination, constipation, somnolence, abdominal pain/discomfort, diaphoresis, anxiety, viral infection, pharyngitis, dyskinesias, and orthostatic hypotension