Levomilnacipran (Fetzima)

What it treats

Levomilnacipran is approved by the U.S. Food and Drug Administration for major depressive disorder in adults. It is not approved for anxiety disorders in the US, though it's been studied for that use.

Prescribers sometimes reach for it when a person has responded partly to an SSRI but still has fatigue or motivation problems, on the theory that the stronger norepinephrine effect might help with drive and energy. That's a reasonable hypothesis rather than a proven advantage; head-to-head trials against other SNRIs are limited.

How it works

Levomilnacipran is a serotonin-norepinephrine reuptake inhibitor, an SNRI. Nerve cells in the brain pass messages using chemical messengers, and serotonin and norepinephrine are two of them. After a cell releases one of these messengers, it normally reabsorbs much of it, a process called reuptake. Levomilnacipran slows the reuptake of both, so more of each stays available between cells.

What sets it apart from other SNRIs is the balance. It affects norepinephrine reuptake about twice as strongly as serotonin reuptake. Other SNRIs (venlafaxine, duloxetine) are the opposite, with a stronger serotonin effect.

How that shift toward norepinephrine translates into different clinical effects isn't fully worked out. In practice it's a bit more activating and a bit rougher on blood pressure and heart rate than the other SNRIs.

Receptor mechanism (detail)

Levomilnacipran is an SNRI that inhibits the norepinephrine transporter (NET) roughly twice as strongly as the serotonin transporter (SERT). This is the opposite balance from venlafaxine and duloxetine, which are more serotonergic. Clinically, this shows up as slightly more activation and slightly more effect on BP and heart rate.

Potency and typical dosing pattern

Ranges are typical framework only, not a prescription for any individual.

Starting dose is 20 mg once daily for 2 days, then 40 mg once daily. The dose can be increased to 80 mg per day, and the maximum is 120 mg per day. Dose adjustments are made in weekly steps or longer.

Safety monitoring

• Blood pressure and heart rate at baseline, at each visit early on, and periodically. This matters more with levomilnacipran than with SSRIs.
• Suicidality in the first 4 weeks, especially under age 25 (FDA boxed warning).
• Serotonin syndrome, avoid MAOIs.
• Bleeding risk with NSAIDs or anticoagulants.
• Hyponatremia in older adults.
• Sexual function.
• Discontinuation, taper slowly.
• Urinary retention risk, especially in older men with prostate enlargement.
• Reassess at 2, 4, and 6 to 8 weeks, then every 3 months.

What to expect

Common side effects

Most people get some side effects. The common ones include:

• Nausea, often the most noticeable early on.
• Constipation.
• Increased sweating.
• Increased heart rate.
• Erectile dysfunction or decreased libido.
• Palpitations.
• Vomiting.
• Trouble sleeping.
• Urinary hesitancy or retention.

Many of the stomach-related effects ease within one to two weeks. Sweating and sexual side effects tend to last as long as the medication is taken rather than fading.

Serious side effects and warnings

Serious problems are uncommon, but a few are worth knowing.

Boxed warning. Like all antidepressants, levomilnacipran carries an FDA boxed warning that it can increase suicidal thoughts and behaviors in children, teenagers, and young adults under 25, especially in the first weeks of treatment or after a dose change. This does not mean the medication harms most people. It means the early period deserves close attention, and that any worsening of mood, agitation, or new thoughts of self-harm should prompt contact with the prescriber promptly.

• Raised blood pressure and heart rate. More prominent with levomilnacipran than with SSRIs or with the more serotonergic SNRIs. This can require dose adjustment or a switch.
• Serotonin syndrome. A rare reaction caused by too much serotonin activity, most likely when levomilnacipran is combined with other drugs that raise serotonin. Signs include agitation, a fast heartbeat, high body temperature, shivering, muscle twitching, and confusion. It is a medical emergency.
• Increased bleeding risk. Levomilnacipran can make bleeding and bruising more likely, especially alongside NSAIDs, aspirin, or blood thinners.
• Low sodium. A drop in blood sodium can happen, more often in older adults.
• Urinary retention. More likely in older men with prostate enlargement, tied to the strong norepinephrine effect.
• Mood switch in bipolar disorder. In people who have bipolar disorder, an antidepressant can sometimes trigger a manic or agitated state, which is one reason an accurate diagnosis matters.
• Narrow-angle glaucoma. Can be aggravated. Screen if there's known risk.

Sexual side effects

Levomilnacipran, like other SNRIs, commonly affects sexual function. It can lower sex drive, delay orgasm or make it hard to reach, and cause arousal or erection difficulties. Rates in the trials were noticeable, particularly erectile dysfunction in men.

These effects usually last as long as the medication is taken, rather than fading like nausea does. They are worth raising with a prescriber, because there are real options: lowering the dose, switching to a medication less likely to cause this such as bupropion, or adding another medication to counter it. A small number of people report sexual side effects that continue after stopping the drug. This is uncommon and not well understood, but it is a real phenomenon and worth knowing about before you start.

Weight, appetite, and sleep

Levomilnacipran is roughly weight-neutral, and some people lose a little appetite early on. Marked weight gain isn't a typical feature.

Its effect on sleep tilts activating for most people, so it's usually taken in the morning. If it disturbs sleep noticeably, that's worth flagging.

Starting and dosing basics

This section is general background, not a dosing instruction for any individual. The right dose is a decision for a prescriber.

Levomilnacipran comes as extended-release capsules taken once a day. The capsule should be swallowed whole (it can also be opened and sprinkled onto applesauce for people who have trouble swallowing pills, per the label). It's started at 20 mg for 2 days and then moved to 40 mg. The maximum dose is 120 mg per day.

Kidney function matters. The dose is lowered in moderate to severe kidney impairment.

Missed doses and interactions

If you miss a dose, take it when you remember unless it's close to the next scheduled dose. Don't double up. Because SNRIs can cause discontinuation symptoms when a dose is missed, taking it consistently matters.

Several interactions matter. Levomilnacipran must not be combined with MAOI antidepressants, and a gap is needed when switching between them. Strong CYP3A4 inhibitors (like ketoconazole and clarithromycin) raise levomilnacipran levels and the dose has to be capped at 80 mg per day. Combining it with other drugs that raise serotonin, such as triptans, tramadol, other antidepressants, or St. John's wort, increases serotonin syndrome risk. NSAIDs and blood thinners add to bleeding risk.

Alcohol is not formally prohibited, but it isn't recommended. Give every prescriber and pharmacist a full list of your medications and supplements, including over-the-counter ones.

Stopping and tapering

Levomilnacipran is not addictive in the usual sense. It doesn't cause cravings or compulsive use. But the body does adjust to it, and stopping suddenly can cause discontinuation symptoms: dizziness, flu-like feelings, irritability, vivid dreams, trouble sleeping, and the brief electrical "brain zap" sensations many people describe.

These symptoms are uncomfortable but not dangerous, and they are more likely the higher the dose and the longer the medication has been taken. The way to avoid them is a gradual taper planned with a prescriber, stepping the dose down over weeks.

Pregnancy and breastfeeding

This is an area where individual circumstances matter and the decision belongs with a clinician. Untreated depression carries its own risks during pregnancy, and levomilnacipran passes into breast milk.

Anyone who is pregnant, planning a pregnancy, or breastfeeding should talk it through with their prescriber so the specific risks and benefits can be weighed.

Cost and generic availability

Levomilnacipran is available as a generic. The brand name is Fetzima. Generic levomilnacipran contains the same active medication and works the same way. It tends to cost more than older generic SNRIs like venlafaxine.

Common questions

How is levomilnacipran different from other SNRIs? It affects norepinephrine more strongly than serotonin, the opposite balance from venlafaxine and duloxetine. In practice that shows up as a slightly more activating feel and a bigger effect on blood pressure and heart rate.

Why check my blood pressure? Levomilnacipran raises blood pressure and heart rate more than SSRIs and more than the more serotonergic SNRIs. Baseline and follow-up checks make sure it isn't causing a problem.

Is levomilnacipran addictive? No, not in the usual sense. It doesn't cause cravings or compulsive use. The body does adapt to it, which is why stopping should be gradual.

Should I take it in the morning or at night? Morning, usually. It tends to be activating.

Can I drink alcohol while taking it? It isn't banned, but it isn't recommended. Alcohol can worsen side effects and undercut the benefit.

Questions to ask your prescriber

• What are we hoping this treats, and how will we know it's working?
• Should my blood pressure be checked while I take it?
• Which side effects should I call about?
• How long should I plan to take it?
• If we decide to stop it later, how would we do that safely?

Sources

This guide draws on current prescribing information and public health references. It is reviewed for clinical accuracy and updated as guidance changes, and current as of June 8, 2026.

• U.S. Food and Drug Administration. Levomilnacipran (Fetzima) prescribing information.
• MedlinePlus, U.S. National Library of Medicine. Levomilnacipran.
• National Institute of Mental Health. Mental health medications.
• American Psychiatric Association. Practice guideline for the treatment of patients with major depressive disorder.
• National Institute for Health and Care Excellence (NICE). NG222, Depression in adults.