Is suzetrigine (Journavx) contraindicated in a patient with multiple sclerosis who has chronic low back pain from a vertebral fracture with sclerosis and neuropathy?

Suzetrigine is NOT Contraindicated in Multiple Sclerosis with Chronic Low Back Pain and Neuropathy

There are no contraindications to suzetrigine (Journavx) in patients with multiple sclerosis, chronic low back pain from vertebral fracture, or neuropathy. The FDA-approved drug label lists only one contraindication: concomitant use with strong CYP3A inhibitors 1.

Contraindications and Warnings

The only absolute contraindication for suzetrigine is:

• Strong CYP3A inhibitors (e.g., itraconazole, clarithromycin, ritonavir) due to 4-fold increases in drug exposure 1

Relative cautions that require dosage adjustment but are not contraindications include:

• Moderate CYP3A inhibitors: reduce to 100 mg initial dose, then 50 mg every 12 hours 1
• Moderate hepatic impairment (Child-Pugh B): use reduced dosing schedule 1
• Severe hepatic impairment (Child-Pugh C): avoid use due to unknown pharmacokinetics 1

Mechanism and Rationale for Use in This Patient

Suzetrigine selectively blocks NaV1.8 voltage-gated sodium channels expressed exclusively in peripheral sensory neurons, including dorsal root ganglion neurons, without crossing the blood-brain barrier 2, 3. This peripheral-only mechanism makes it particularly suitable for patients with neurological conditions like multiple sclerosis because:

• No central nervous system effects: Unlike opioids, suzetrigine does not cause sedation, respiratory depression, or cognitive impairment 2, 4
• Neuropathic pain efficacy: The drug inhibits pain signal transmission in peripheral nociceptors, which is relevant for neuropathy 2, 5
• No addiction potential: Preclinical and clinical studies show no evidence of dependence or abuse liability 2, 6

Evidence for Chronic Pain and Neuropathy

While suzetrigine is FDA-approved only for moderate to severe acute pain 4, there is emerging evidence for neuropathic conditions:

• A case report demonstrated successful use in a 16-year-old with hereditary neuropathy undergoing foot surgery, with rapid pain intensification within 24 hours of stopping the drug 5
• Ongoing trials are evaluating suzetrigine for chronic neuropathic conditions including diabetic peripheral neuropathy and lumbosacral radiculopathy 7, 3
• The mechanism of NaV1.8 inhibition is particularly relevant for neuropathic pain, as this channel plays a specialized role in pain amplification 8, 2

Comparison to Guideline-Recommended Therapies

For chronic low back pain with neuropathy, established guidelines recommend:

• First-line for neuropathic pain: Gabapentin or pregabalin 9, 10
• Tricyclic antidepressants or SNRIs: For chronic low back pain and neuropathic pain 11, 9
• NSAIDs: For mechanical low back pain, though less effective for neuropathic components 11, 12
• Avoid long-term opioids: Particularly in chronic multisymptom illness 13

Suzetrigine could serve as an adjunct or alternative when these first-line agents are insufficient, contraindicated, or poorly tolerated 7.

Practical Considerations

Drug interactions to monitor:

• Suzetrigine induces CYP3A, potentially reducing efficacy of CYP3A substrates including some hormonal contraceptives (except levonorgestrel and norethindrone) 1
• Avoid grapefruit products during treatment 1

Dosing for this patient (assuming normal hepatic function and no moderate CYP3A inhibitors):

• Initial dose: 100 mg on empty stomach 1
• Doses 2-4: 50 mg every 12 hours starting 12 hours after initial dose 1
• Dose 5 onward: 50 mg every 24 hours 1

Common adverse effects are generally mild:

• Pruritus, muscle spasms, elevated creatine phosphokinase, rash 1
• Discontinuation rate due to adverse events was only 0.6% in clinical trials 1

Clinical Bottom Line

Proceed with suzetrigine in this patient, as there are no contraindications related to multiple sclerosis, chronic low back pain, vertebral fracture, or neuropathy 1. The peripheral-selective mechanism makes it theoretically advantageous in patients with neurological disease 2, 3. However, recognize that current FDA approval is limited to acute pain, and evidence for chronic pain conditions is still emerging 7, 4. Consider suzetrigine as part of a multimodal approach alongside guideline-recommended therapies for neuropathic pain such as gabapentin or SNRIs 9, 10.