How should I further evaluate and manage a 42-year-old female with a four-year history of bilateral restless‑leg symptoms that improve with movement, who has hypothyroidism treated with levothyroxine 100 µg daily, has been taking omeprazole 20 mg each morning for two years, and medroxyprogesterone 10 mg daily for four months for polycystic ovary syndrome, with stable oxygen saturation, pulse, blood pressure, weight 70 kg, height 150 cm (BMI ≈31)?

Approach to Restless Legs Syndrome in a 42-Year-Old Female with Hypothyroidism

Check serum ferritin and transferrin saturation immediately, optimize thyroid control with TSH testing, and discontinue omeprazole—then initiate gabapentin or pregabalin as first-line pharmacotherapy for this 4-year history of restless legs syndrome.

Initial Diagnostic Workup

Iron Studies (Critical First Step)

The most important initial investigation is iron status assessment 1:

• Serum ferritin (target >75 ng/mL for RLS treatment consideration)
• Transferrin saturation (target >20%)

Iron deficiency is a reversible cause of RLS and must be addressed before or concurrent with other treatments. The 2025 AASM guidelines strongly recommend IV ferric carboxymaltose for patients with appropriate iron parameters 1.

Thyroid Function Assessment

Despite 5 years of levothyroxine therapy, verify TSH and free T4 levels 2:

• Inadequate thyroid replacement can contribute to RLS symptoms 3
• Recent evidence shows untreated or undertreated Hashimoto's thyroiditis significantly increases RLS incidence and severity 3
• The omeprazole use (discussed below) may be interfering with levothyroxine absorption

Medication Review: Critical Omeprazole Issue

Discontinue the 2-year self-medication with omeprazole 20 mg for multiple reasons:

1. Potential levothyroxine malabsorption: While one study 4 showed no clinically significant TSH changes with omeprazole, the FDA label 2 explicitly warns that "persistent clinical and laboratory evidence of hypothyroidism despite an apparent adequate replacement dose may be evidence of inadequate absorption"

2. Iron malabsorption: Chronic proton pump inhibitor use impairs iron absorption, potentially worsening the iron deficiency that commonly underlies RLS

3. No clear indication: Two years of self-medication without documented need warrants reassessment

First-Line Pharmacological Treatment

Recommended Initial Therapy: Alpha-2-Delta Ligands

Start gabapentin or pregabalin as first-line treatment 1:

• Gabapentin: Strong recommendation, moderate certainty of evidence 1
• Pregabalin: Strong recommendation, moderate certainty of evidence 1

These are now preferred over dopamine agonists due to the major problem of augmentation (iatrogenic worsening of RLS with long-term dopaminergic therapy) 1, 5.

Why NOT Dopamine Agonists First

The 2025 AASM guidelines represent a substantial change from previous recommendations 1:

• Pramipexole, ropinirole, rotigotine, and levodopa now receive conditional recommendations AGAINST standard use 1
• They may be considered only for short-term use in patients who prioritize immediate symptom relief over long-term adverse effects 1
• Augmentation occurs commonly and leads to progressive worsening requiring complex medication switches 5

Iron Supplementation Strategy

If Iron Deficiency Confirmed

Based on iron study results 1:

• IV ferric carboxymaltose: Strong recommendation if ferritin and transferrin saturation are low 1
• Oral ferrous sulfate: Conditional recommendation, moderate certainty 1
• IV formulations are more effective but oral iron is more accessible

If Iron Studies Normal

Proceed directly with alpha-2-delta ligand therapy without iron supplementation.

Additional Considerations

Address Cardiovascular Risk

• BP 130/90 mmHg: Borderline hypertension requiring monitoring
• BMI ≈31: Obesity increases cardiovascular risk
• These factors are relevant given the patient's age and hormone therapy 6

Medroxyprogesterone Monitoring

The FDA label 6 warns about increased risks of cardiovascular events and thrombosis with progestin therapy. Given her borderline hypertension and obesity, ensure:

• Regular cardiovascular risk assessment
• Discussion of whether PCOS treatment continuation is necessary
• Consideration of alternative PCOS management if RLS treatment requires additional medications

Hypothyroidism Optimization

After stopping omeprazole, recheck TSH in 6-8 weeks 2:

• Ensure TSH is within normal range
• Adjust levothyroxine dose if needed
• Inadequately treated hypothyroidism may perpetuate RLS symptoms 3

Common Pitfalls to Avoid

1. Starting dopamine agonists first: This outdated approach leads to augmentation in many patients, requiring difficult medication transitions later 1, 5

2. Ignoring iron status: Even "normal" ferritin may be suboptimal for RLS (threshold is higher than for anemia) 1

3. Continuing omeprazole without indication: This may worsen both thyroid control and iron absorption

4. Undertreating hypothyroidism: Suboptimal thyroid replacement can contribute to RLS pathophysiology 3

Treatment Algorithm Summary

1. Immediate: Order ferritin, transferrin saturation, TSH, free T4
2. Discontinue: Omeprazole (unless documented indication exists)
3. Initiate: Gabapentin or pregabalin for RLS symptoms 1
4. Add iron: If studies show deficiency (IV preferred, oral acceptable) 1
5. Optimize thyroid: Adjust levothyroxine if TSH abnormal after stopping omeprazole 2
6. Reassess: In 4-6 weeks for symptom response and laboratory follow-up

This approach prioritizes treatments with the best long-term outcomes while addressing reversible secondary causes of RLS 1, 5.