Is peripheral neuropathy the more accurate cause of restless‑legs‑syndrome‑like symptoms that are unresponsive to dopamine agonists, and should treatment target the neuropathy rather than using dopamine agonists?

Distinguishing True RLS from Peripheral Neuropathy Mimics

No—peripheral neuropathy causing RLS-like symptoms represents a distinct clinical entity that requires different diagnostic and therapeutic approaches, and these neuropathy-related symptoms often do respond to dopamine agonists when true RLS coexists. 1, 2

The Critical Diagnostic Distinction

The key issue is that peripheral neuropathy can produce sensory symptoms that superficially resemble RLS but lack the core diagnostic features:

• Neuropathic pain and paresthesias are commonly mistaken for RLS, particularly when patients have difficulty describing their symptoms. 2
• Screen-positive rates are misleadingly high in neuropathy patients (26.5%), but only 46% of these are confirmed as true RLS upon expert evaluation, compared to 80% confirmation in controls. 2
• The most common false-positive features are cramps and paresthesias without true diurnal variation or rest exacerbation—these patients do not have RLS and should not receive dopamine agonists. 2

When Neuropathy and RLS Actually Coexist

True RLS prevalence is not elevated in acquired neuropathies (9.2%) compared to controls (8.2%), but is significantly increased in hereditary neuropathies (19.4%). 2

When genuine RLS occurs in neuropathy patients:

• Therapeutic response to dopamine agonists is similar between primary RLS and neuropathic RLS patients at 6 months and 1 year. 1
• Patients with both conditions more commonly have a family history of RLS (37% vs 15%) and are younger (mean age 49.9 vs 61.4 years), suggesting the RLS is a separate inherited condition rather than caused by the neuropathy. 2

Current Treatment Algorithm for RLS-Like Symptoms in Neuropathy

Step 1: Confirm True RLS Diagnosis

• Verify all four diagnostic criteria: urge to move with uncomfortable sensations, worsening at rest, relief with movement, and evening/nighttime predominance. 3
• Distinguish from nocturnal leg cramps, which have different pathophysiology. 4
• Asymmetric symptoms favor primary RLS (25% asymmetric) over neuropathic mimics (0% asymmetric). 1

Step 2: Assess Iron Status

• Check serum ferritin and transferrin saturation in all patients. 5
• Initiate iron repletion if ferritin ≤100 ng/mL or transferrin saturation <20%. 5
• Intravenous ferric carboxymaltose 1000 mg is strongly recommended as first-line iron therapy (AASM 2025, strong recommendation). 6, 4, 5

Step 3: First-Line Pharmacologic Therapy (If True RLS Confirmed)

Gabapentinoids receive strong recommendations as first-line agents (AASM 2025):

• Gabapentin enacarbil, gabapentin, or pregabalin are all strongly recommended. 4, 5, 3
• These agents improve RLS symptoms in approximately 70% of patients vs 40% with placebo (p<0.001). 3
• Gabapentinoids also improve neuropathic pain, making them particularly suitable when both conditions coexist. 7

Step 4: Avoid Dopamine Agonists as First-Line

Dopamine agonists (pramipexole, ropinirole, rotigotine) are not recommended as first-line therapy due to:

• 7-10% annual risk of augmentation (iatrogenic worsening of RLS symptoms). 6, 4, 3
• Prior dopaminergic treatment impairs future responses to both dopaminergic and non-dopaminergic therapies, even before clinical augmentation develops. 8

Step 5: Second-Line Options for Refractory Cases

If gabapentinoids fail or are not tolerated:

• Extended-release oxycodone or methadone (5-10 mg daily) are conditionally recommended (AASM 2025). 6, 4
• Opioids show minimal augmentation risk with no confirmed cases in major trials. 6

Treatment of Pure Neuropathic Pain (Not RLS)

For patients whose symptoms are determined to be neuropathic pain rather than true RLS:

• First-line agents include tricyclic antidepressants, duloxetine, pregabalin, or gabapentin for painful diabetic peripheral neuropathy. 9
• These patients should not receive dopamine agonists, as their symptoms are not dopamine-responsive. 9

Common Pitfalls to Avoid

• Do not assume all leg discomfort in neuropathy patients is "just the neuropathy"—true RLS can coexist and requires specific treatment. 2
• Do not start dopamine agonists without confirming true RLS diagnosis—this exposes patients to augmentation risk without benefit. 4, 8
• Do not overlook iron deficiency—correction may resolve symptoms without need for other medications. 5, 3
• Do not continue medications that exacerbate RLS (serotonergic antidepressants, dopamine antagonists, centrally acting antihistamines). 5, 3