(FDA approved in bold)

• Depression
  
• Migraine prophylaxis
  
• Tension-type headache prophylaxis
  
• Diabetic neuropathy
  
• Post-herpetic neuralgia
  
• Other painful peripheral neuropathies
  
• Back or neck pain
  
• Phantom limb pain
  
• Fibromyalgia
  
• Bulimia nervosa
  
• Insomnia
  
• Anxiety
  
• Nocturnal enuresis
  
• ADHD
  
• Smoking cessation

• Blocks serotonin and norepinephrine reuptake pumps, increasing their levels within hours, but antidepressant effect takes weeks. Effect is more likely related to adaptive changes in serotonin and norepinephrine receptor systems over time
  
• It also has antihistamine properties, which most likely causes the sedation treating insomnia

• Migraines – effective in as little as 2 weeks, but can take up to 3 months on a stable dose to see full effect
  
• Neuropathic pain – usually some effect within 4 weeks
  
• Depression – 2 weeks but up to 2 months for full effect
  
• Insomnia, anxiety, depression – may be effective immediately, but effects often delayed 2 to 4 weeks

• Migraine – goal is a 50% or greater decrease in migraine frequency or severity. Consider tapering or stopping if headaches remit for more than 6 months or if considering pregnancy
  
• Neuropathic pain – the goal is to reduce pain intensity and symptoms, but usually does not produce remission
  
• Insomnia – continue to use if tolerated and encourage good sleep hygiene
  
• Depression – continue to use and monitor for AEs. Usually not first-line treatment for depression

• Increase to highest tolerated dose
  
• Migraine: address other issues, such as medication overuse, other coexisting medical disorders, such as anxiety, and consider changing to another agent or adding a second agent
  
• Chronic pain: either change to another agent or add a second agent
  
• Insomnia: if no sedation occurs despite adequate dosing, stop and change to another agent

• Migraine: For some patients, low-dose polytherapy with 2 or more drugs may be better tolerated and more effective than high-dose monotherapy. May use in combination with AEDs, antihypertensives, natural products, and non-medication treatments, such as biofeedback, to improve headache control
  
• Chronic pain: AEDs such as gabapentin, pregabalin, carbamazepine, and capsaicin, mexiletine are agents used for neuropathic pain. Opioids are appropriate for long-term use in some cases but require careful monitoring

• Consider checking ECG for QTc prolongation at baseline and when increasing dose, especially in those with a personal or family history of QTc prolongation, cardiac arrhythmia, heart failure or recent myocardial infarction. In patients on diuretics, measure potassium and magnesium at baseline and periodically