gabapentin + pregabalin + duloxetine + amitriptyline

This is a combination therapy approach for treating neuropathic pain, particularly diabetic peripheral neuropathic pain (DPNP). While not typically administered as a single formulation, these medications are used in various combinations as part of treatment pathways for patients with neuropathic pain. Clinical trials like OPTION-DM have examined different combinations of these medications, finding that combination therapy can provide additional pain relief in patients whose pain does not respond adequately to monotherapy. The medications work through different mechanisms: pregabalin and gabapentin are gabapentinoids that bind to the α2δ subunit of voltage-gated calcium channels; duloxetine is a serotonin-norepinephrine reuptake inhibitor (SNRI); and amitriptyline is a tricyclic antidepressant (TCA).