Generic Name

Luxiq

Mechanism

• Selective blockade of Na⁺ channel subtypes Nav1.7/1.8 – the key mediators of nociceptive signal initiation in peripheral afferents.
• Inhibition reduces voltage‑gated sodium influx, dampening ectopic action‑potential generation in injured nerves.
• Minimal interaction with other ion channels (Na⁺/K⁺ ATPase, L‑type Ca²⁺ channels) contributes to its low off‑target toxicity.

Pharmacokinetics

• Absorption: Rapid, oral bioavailability ≈ 60 %; peak plasma concentration (Tmax) ~ 1.5 h post‑dose.
• Distribution: Moderate protein binding (≈ 45 % to albumin). Volume of distribution (Vd) ≈ 2.5 L/kg.
• Metabolism: Primarily CYP3A4‑mediated oxidative clearance; minor CYP1A2 contribution.
• Excretion: 55 % renally (urine, unchanged), 45 % hepatobiliary.
• Elimination half‑life: ~ 12 h, supporting once‑daily administration.

Indications

• Chronic neuropathic pain secondary to radiculopathy, diabetic peripheral neuropathy, post‑herpetic neuralgia.
• Acute postoperative neuropathic discomfort in patients with contraindications to opioids.

Contraindications

• Absolute contraindications:
• Severe hepatic impairment (Child‑Pugh C).
• Concomitant use of potent CYP3A4 inhibitors (ketoconazole, clarithromycin).
• Warnings:
• Potential for QTc prolongation; caution in patients with congenital long QT syndrome or concurrent QT‑prolonging drugs.
• Rare hepatotoxicity; monitor liver function.

Dosing

• Adults:
• *Initiation*: 100 mg PO once daily (evening).
• *Titration*: Increase by 100 mg every 3–5 days based on analgesic response & tolerability.
• *Maximum dose*: 400 mg/day.
• Children (12‑17 yrs): 0.5–1 mg/kg/day; titrate cautiously.
• Renal impairment (CrCl 30–59 mL/min): Reduce dose by 25 % to 300 mg/day.
• Avoidance of food to maintain peak absorption; distribution unaffected by meals.

Adverse Effects

Common (≥ 5 %)
• Dizziness, light‑headedness
• Nausea, mild GI upset
• Mild fatigue, somnolence

Serious (≤ 1 %)
• Rhabdomyolysis (rare, associated with high serum CPK)
• Hepatotoxicity (elevated ALT/AST > 5 × ULN)
• QTc prolongation (> 500 ms)
• Severe allergic reactions (anaphylaxis)

Management of adverse events – discontinue if serious toxicity; for mild side‑effects, advise hydration and gradual dose adjustment.

Monitoring

• Baseline: CBC, CMP (LFT, renal panel), ECG (QTc).
• Follow‑up:
• LFTs every 4 weeks for first 3 months, then 3 monthly if stable.
• ECG at baseline, then after any drug change or if QTc > 450 ms.
• Creatinine at baseline and every 8 weeks in CKD.
• Patient education: Report muscle pain, dark urine, palpitations promptly.

Clinical Pearls

• CYP3A4 Interactions: Co‑prescribe with medium‑strong inhibitors only with dose reduction; avoid strong inhibitors.
• Once‑daily Convenience – improve adherence in poly‑pharmacy elderly patients.
• Avoid with Poorly Soluble Prodrugs: Concomitant administration with poorly soluble lipids may diminish Luxiq absorption.
• Bioavailability Boost: 5 % increase in peak concentration when taken on an empty stomach; confirm by patient counseling.
• Monitor for Rhabdomyolysis – signal in patients with high creatine kinase after dose escalation.

*Luxiq* represents a targeted approach to neuropathic pain management, leveraging its selective blockade of Nav1.7/1.8 channels to deliver effective analgesia with minimal systemic side‑effects.