What are the available common Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)?

From the Guidelines

The most common SNRIs (Serotonin-Norepinephrine Reuptake Inhibitors) available are venlafaxine, desvenlafaxine, duloxetine, and levomilnacipran, as indicated in the latest clinical practice guideline 1. These medications are typically used to treat depression, anxiety disorders, and sometimes chronic pain conditions.

• Venlafaxine (Effexor)
• Duloxetine (Cymbalta)
• Desvenlafaxine (Pristiq)
• Levomilnacipran (Fetzima) Starting doses vary but are often lower, with gradual increases as needed. For example, venlafaxine might start at 37.5 mg daily, increasing to 75-225 mg daily as tolerated. SNRIs work by increasing the levels of both serotonin and norepinephrine in the brain, which can help regulate mood, reduce anxiety, and alleviate pain. They are generally well-tolerated but can cause side effects like nausea, dry mouth, and increased sweating, as noted in a recent study on the treatment of pain in diabetic neuropathy 1. It's essential to start and stop these medications under medical supervision due to potential withdrawal effects. Patients should be aware that SNRIs may take several weeks to reach full effectiveness, and regular follow-ups with a healthcare provider are necessary to monitor progress and adjust dosage if needed. The choice of medication for anxiety within the SNRI class may also be governed by other considerations such as pharmacokinetics, pharmacodynamics, tolerability, cost, insurance formularies, and unique risks leading to warnings or precautions, as discussed in the clinical practice guideline 1.

From the FDA Drug Label

Duloxetine delayed-release capsules are selective serotonin and norepinephrine reuptake inhibitor (SNRI) for oral administration. Levomilnacipran extended-release capsules... Serotonin-norepinephrine reuptake inhibitors (SNRIs), including levomilnacipran, can precipitate serotonin syndrome, a potentially life-threatening condition.

The available common Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs) are:

• Duloxetine 2
• Levomilnacipran 3

From the Research

Available SNRIs

The following are some common Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs):

• Venlafaxine 4, 5, 6, 7, 8
• Desvenlafaxine 4
• Duloxetine 4, 5, 6, 7, 8
• Milnacipran 4, 5, 6, 8
• Levomilnacipran 4

Characteristics of SNRIs

These SNRIs have varying levels of potency and binding affinity ratios for serotonin and norepinephrine transporters 4. They are used to treat a variety of conditions, including major depressive disorder (MDD), generalized anxiety disorder, social anxiety disorder, panic disorder, diabetic peripheral neuropathic pain, fibromyalgia, and musculoskeletal pain 4, 5, 7.

Efficacy and Tolerability

The efficacy and tolerability of SNRIs can vary within the class 5. Venlafaxine, for example, may be less well-tolerated due to its dose-dependent cardiovascular effects, whereas duloxetine and milnacipran appear to be better tolerated 5. A meta-analysis comparing duloxetine and venlafaxine-XR found that both drugs had higher remission and response rates than placebo, with no statistically significant differences between the two drugs 7.

Mechanism of Action

SNRIs work by inhibiting the reuptake of both serotonin and norepinephrine, which can provide a profile of effectiveness comparable to tricyclic antidepressants and higher than selective serotonin reuptake inhibitors 8. They have a lower risk of adverse effects due to their lack of affinity for certain receptors and their limited action on monoamine oxidase 8.