Presumably desensitizes both serotonin 1A receptors and beta adrenergic receptors
Weak noncompetitive NMDA-receptor antagonist (high doses), which may contribute to actions in chronic pain
Since dopamine is inactivated by norepinephrine reuptake in frontal cortex, which largely lacks dopamine transporters, milnacipran can increase dopamine neurotransmission in this part of the brain
How Long Until It Works
Onset of therapeutic actions usually not immediate, but often delayed 2 to 4 weeks
If it is not working within 6 to 8 weeks, it may require a dosage increase or it may not work at all
May continue to work for many years to prevent relapse of symptoms in depression
If It Works
The goal of treatment of depression is complete remission of current symptoms as well as prevention of future relapses
The goal of treatment of fibromyalgia and chronic neuropathic pain is to reduce symptoms as much as possible, especially in combination with other treatments
Treatment of depression most often reduces or even eliminates symptoms, but is not a cure since symptoms can recur after medicine stopped
Treatment of fibromyalgia and chronic neuropathic pain may reduce symptoms, but rarely eliminates them completely, and is not a cure since symptoms can recur after medicine is stopped
Continue treatment of depression until all symptoms are gone (remission)
Once symptoms of depression are gone, continue treating for 1 year for the first episode of depression
For second and subsequent episodes of depression, treatment may need to be indefinite
Use in fibromyalgia and chronic neuropathic pain may also need to be indefinite, but long-term treatment is not well-studied in these conditions
If It Doesn’t Work
Many depressed patients only have a partial response where some symptoms are improved but others persist (especially insomnia, fatigue, and problems concentrating)
Other depressed patients may be nonresponders, sometimes called treatment-resistant or treatment-refractory
Some depressed patients who have an initial response may relapse even though they continue treatment, sometimes called “poop-out”
Consider increasing dose, switching to another agent or adding an appropriate augmenting agent
Consider psychotherapy
Consider evaluation for another diagnosis or for a comorbid condition (e.g., medical illness, substance abuse, etc.)
Some patients may experience apparent lack of consistent efficacy due to activation of latent or underlying bipolar disorder, and require antidepressant discontinuation and switch to a mood stabilizer
Best Augmenting Combos for Partial Response or Treatment-Resistance
Augmentation experience is limited compared to other antidepressants
Benzodiazepines can reduce insomnia and anxiety
Adding other agents to milnacipran for treating depression could follow the same practice for augmenting SSRIs or other SNRIs if done by experts while monitoring carefully in difficult cases
Although no controlled studies and little clinical experience, adding other agents for treating fibromyalgia and chronic neuropathic pain could theoretically include gabapentin, tiagabine, other anticonvulsants, or even opiates if done by experts while monitoring carefully in difficult cases
Mirtazapine, bupropion, reboxetine, atomoxetine (use combinations of antidepressants with caution as this may activate bipolar disorder and suicidal ideation)
Modafinil, especially for fatigue, sleepiness, and lack of concentration
Mood stabilizers or atypical antipsychotics for bipolar depression, psychotic depression or treatment-resistant depression
Hypnotics or trazodone for insomnia
Classically, lithium, buspirone, or thyroid hormone
Tests
Check blood pressure before initiating treatment and regularly during treatment