Correct Answer: C. Gabapentin
The clinical presentation—nocturnal paresthesias ("creepy crawling"), sleep disruption, and relief with movement—is pathognomonic for Restless Legs Syndrome (RLS). RLS is a sensorimotor disorder characterized by an irresistible urge to move the legs, typically triggered at rest and relieved by activity. The first-line pharmacological treatment in India follows international guidelines: gabapentin (or pregabalin) is the preferred agent for RLS, particularly when iron deficiency or secondary causes have been excluded. Gabapentin works by modulating calcium channels and reducing neuronal excitability in the spinal cord and brain, thereby suppressing the abnormal sensations and motor restlessness. While dopamine agonists (like pramipexole) are also used, gabapentin is increasingly favored as first-line due to lower risk of augmentation (worsening of symptoms with prolonged use)—a major limitation of dopaminergic agents in RLS. The patient's age (25 years) and female sex fit the typical RLS demographic. Iron deficiency is a known secondary cause of RLS and should be screened, but iron tablets alone are not the primary treatment for idiopathic RLS; they are adjunctive only if ferritin is low. Gabapentin's efficacy in RLS is well-established in Indian clinical practice and aligns with current NEET PG curriculum emphasis on non-dopaminergic first-line therapy.
Why the other options are wrong
A. Pramipexole — Pramipexole is a dopamine agonist and was historically a first-line RLS agent. However, it carries a significant risk of augmentation—paradoxical worsening of symptoms with prolonged use—and impulse control disorders. Modern guidelines (including Indian practice) now reserve dopamine agonists for second-line use or specific RLS phenotypes. Gabapentin is preferred as first-line due to lower augmentation risk and better long-term tolerability. B. Iron tablets — Iron deficiency is a secondary cause of RLS and should be screened (serum ferritin <75 ng/mL). Iron supplementation is indicated only if deficiency is confirmed. However, iron tablets alone are not the primary treatment for idiopathic RLS in a patient with normal iron stores. This is an NBE trap: students may conflate 'iron deficiency causes RLS' with 'iron is the treatment,' missing that gabapentin addresses the primary neurophysiological dysfunction. D. Vitamin B12 — B12 deficiency can cause peripheral neuropathy and paresthesias, but it does not cause RLS specifically. B12 supplementation is indicated only if deficiency is documented (serum B12 <200 pg/mL or elevated methylmalonic acid). The clinical picture—nocturnal onset, relief with movement, sleep disruption—is RLS, not B12 neuropathy. This is a distractor exploiting overlap between 'paresthesias' and 'vitamin deficiency.'
High-Yield Facts
- RLS first-line pharmacotherapy: Gabapentin (300–3600 mg/day) or pregabalin (150–600 mg/day); dopamine agonists now second-line due to augmentation risk.
- RLS diagnostic criteria: Irresistible urge to move legs, worse at rest and evening/night, relieved by movement, and sleep disturbance—all four required.
- Secondary RLS causes: Iron deficiency (ferritin <75 ng/mL), chronic kidney disease, pregnancy, and peripheral neuropathy; always screen before starting symptomatic therapy.
- Augmentation in RLS: Paradoxical worsening of symptoms with prolonged dopamine agonist use; occurs in ~30% of patients, making gabapentin/pregabalin preferred.
- RLS epidemiology in India: Prevalence 5–10% in general population; female predominance (2:1); onset typically 20–40 years; often underdiagnosed.
Mnemonics
RLS Treatment Ladder (NEET PG) Gabapentin/Pregabalin (first-line) → Dopamine agonists (second-line) → Opioids (third-line, refractory). Remember: GDO = 'Go Dopamine Only if gabapentin fails.' RLS Diagnostic Quartet URGE: Urge to move, Rest-triggered, Get relief with movement, Evening/night worse. All four must be present.
NBE Trap
NBE pairs RLS with 'iron deficiency' and 'paresthesias' to lure students into choosing iron or B12 supplementation, conflating secondary causes with primary treatment. The key discriminator is the nocturnal, movement-relieved, sleep-disrupting pattern—classic RLS, not nutritional neuropathy—which mandates gabapentin as first-line.
Clinical Pearl
In Indian outpatient practice, RLS is frequently missed because patients describe it as "leg pain" or "restlessness" rather than the classic "creepy crawling." Always ask: "Does moving your legs help?" If yes + nocturnal + sleep loss, start gabapentin 300 mg at night and titrate. Screen ferritin and renal function first—many Indian patients have iron deficiency anemia, which may be a reversible secondary cause.
_Reference: Harrison Ch. 383 (Sleep Disorders); Robbins Ch. 28 (Nervous System); KD Tripathi Ch. 10 (Anticonvulsants & Gabapentin)_