What is the optimal pain management strategy for a patient with cervical and arm pain, currently tapering gabapentin (Neurontin) and previously responsive to duloxetine (Cymbalta)?

From the Guidelines

I strongly recommend transitioning this patient from gabapentin to duloxetine for his cervical pain that radiates to his right pectoralis and left arm pain, as duloxetine has been shown to be effective in treating neuropathic pain and has a favorable safety profile, as supported by the most recent and highest quality study 1. The patient should continue his current gabapentin taper while starting duloxetine 30 mg in the morning and 60 mg in the evening. This approach aligns with current guidelines that do not recommend gabapentin as first-line therapy for musculoskeletal or neural pain. The patient has previously reported positive results with Cymbalta (duloxetine) when he was "on the streets," suggesting it may be effective for his pain management. Duloxetine works by inhibiting the reuptake of serotonin and norepinephrine, which helps modulate pain signals in the central nervous system. This dual-action mechanism makes it particularly effective for neuropathic and musculoskeletal pain. The split dosing (30 mg morning, 60 mg evening) may help minimize side effects while providing adequate pain control throughout the day. The patient has agreed to this plan of care, which should facilitate adherence to the new medication regimen. Some key points to consider when prescribing duloxetine include:

• Starting with a low dose and gradually increasing as needed and tolerated, as recommended by the guidelines 1
• Monitoring for potential side effects, such as nausea, and adjusting the dose accordingly, as noted in the study 1
• Considering the patient's medical history and potential interactions with other medications, as highlighted in the study 1
• Regularly assessing the patient's pain and adjusting the treatment plan as needed, as suggested by the guidelines 1. It's also important to note that the use of opioids, such as tapentadol, is not generally recommended as a first- or second-line therapy for neuropathic pain due to the high risk of addiction and safety concerns, as stated in the study 1. Overall, transitioning the patient to duloxetine and continuing the gabapentin taper is a reasonable and evidence-based approach to managing his pain, as supported by the most recent and highest quality study 1.

From the FDA Drug Label

The efficacy of duloxetine delayed-release capsules in chronic musculoskeletal pain in adults was assessed in two double-blind, placebo-controlled, randomized clinical trials of 13-weeks duration (Studies CLBP-1 and CLBP-2), and one of 12-weeks duration (CLBP-3) Patients in all trials had no signs of radiculopathy or spinal stenosis. Study CLBP-1: Two hundred thirty-six adult patients (N=115 on duloxetine delayed-release capsules, N=121 on placebo) enrolled and 182 (77%) completed 13-week treatment phase After 13 weeks of treatment, patients taking duloxetine delayed-release capsules 60 to 120 mg daily had a significantly greater pain reduction compared to patients taking placebo.

The patient's condition of pain in the cervical area that radiated to the right pectoralis and pain in the left arm may be considered as chronic musculoskeletal pain.

• The duloxetine dosage is started at 30 mg once daily for one week, then increased to 60 mg once daily.
• If the patient has less than 30% reduction in average daily pain and can tolerate 60 mg once daily, the dosage may be increased to 120 mg once daily.
• The patient's old scar on the left wrist is not directly relevant to the current treatment with duloxetine.
• Duloxetine has been shown to be effective in reducing pain in patients with chronic musculoskeletal pain 2.
• The efficacy of duloxetine in chronic musculoskeletal pain has been demonstrated in clinical trials, with patients taking duloxetine having significantly greater pain reduction compared to those taking placebo 2.

From the Research

Patient's Condition and Treatment

• The patient is a 39-year-old male experiencing pain in his cervical area that radiates to his right pectoralis and also complains of pain in his left arm.
• He is currently in a gabapentin taper and has a history of trying Cymbalta, which worked for him in the past.
• The patient has been prescribed duloxetine 30 mg QAM and duloxetine 60 mg QPM while continuing with the gabapentin taper.

Duloxetine Dosage and Efficacy

• A study published in 2007 3 compared the effects of starting doses of duloxetine taken with or without food on tolerability and efficacy in patients with major depressive disorder.
• The study found that starting duloxetine at 30 mg q.a.m. for 1 week with or without food or starting duloxetine at the therapeutic dose of 60 mg q.a.m. with food can improve the initial tolerability of the medication.
• Another study published in 2005 4 compared the stabilized duloxetine dose through approximately 12 weeks of treatment in patients initiating duloxetine therapy with that in patients switching to duloxetine from selective serotonin reuptake inhibitors or venlafaxine.
• The study found that the efficacy of duloxetine in patients switching from selective serotonin reuptake inhibitor/venlafaxine did not differ significantly from that observed in untreated patients initiating duloxetine therapy.

Comparison of Duloxetine and Gabapentin

• A study published in 2019 5 compared the effectiveness of duloxetine and gabapentin on painful diabetic peripheral polyneuropathy.
• The study found that both duloxetine and gabapentin are effective for the treatment of painful diabetic peripheral polyneuropathy, but duloxetine has better medication compliance.
• Another study published in 2019 6 evaluated the efficacy of duloxetine and gabapentin in patients with moderate to severe knee osteoarthritis.
• The study found that both gabapentin and duloxetine have similar and acceptable effects in pain reduction and improvement of functional status in patients with knee osteoarthritis at the end of the third month's treatment.

Predictors of High-Dose Duloxetine Prescriptions

• A study published in 2011 7 examined dosing patterns and pretreatment predictors of high-dose duloxetine therapy for patients with major depressive disorder.
• The study found that patients treated with >60 mg/d for at least 2 months were older, were more likely to have been treated by a psychiatrist, had greater comorbidity, and had used more health care resources and psychotropic and pain medications in the previous year.