Duloxetine (Cymbalta)

What is duloxetine?

Duloxetine is known as Cymbalta in the United States, the UK, and Japan alike (サインバルタ on Japanese packaging). It belongs to the SNRI group of antidepressants: it works on serotonin and noradrenaline, two chemical messengers linked to mood, anxiety, and how we feel pain.

How is it different from other antidepressants?

• Mood and pain together: in Japan it's approved not only for depression but for several chronic pain conditions, a double life few antidepressants have
• Works on two systems at once: serotonin for mood, noradrenaline for drive and energy
• Often chosen when low mood travels with physical aches, since one medicine can address both
• Once daily and well established worldwide

What is it used for in Japan?

• Depression
• Chronic pain of several types: nerve pain from diabetes, fibromyalgia, chronic low back pain, and osteoarthritis pain

How does it help?

By gradually increasing serotonin and noradrenaline in the brain, it eases low mood over time, and can also calm certain kinds of pain. The full effect often takes a few weeks. If you don't feel better right away, that's normal; keep taking it as prescribed.

What should I tell my doctor before starting?

A few situations rule it out entirely; your doctor will choose something else if any of these apply:

• A past allergic reaction to duloxetine
• Taking, or recently stopping, an MAO inhibitor (a medicine for depression or Parkinson's); these can't overlap
• Severe liver problems
• Severe kidney problems
• Closed-angle (narrow-angle) glaucoma that isn't well controlled; other types of glaucoma are usually fine to work around

And tell your doctor first if any of these apply; these usually just need adjustments or a closer eye:

• Other antidepressants, tramadol (a painkiller), or migraine triptans
• Blood thinners, or regular painkillers like ibuprofen
• A history of seizures, or bipolar disorder
• Being older, or taking water tablets (diuretics)
• Pregnant, planning to be, or breastfeeding (see the section below)

Your doctor may also check your blood pressure now and then, as duloxetine can raise it slightly in some people.

How do I take it, and what if I miss a dose?

Duloxetine is taken once a day, after breakfast (the Japanese label specifies the morning), and the capsule is swallowed whole.

• If you miss a dose: take it when you remember that day, or just skip it if the next one is close. Never take a double dose to catch up
• The first week or two is when nausea is most likely; taking it after food helps, and it usually fades
• Rarely, the early weeks bring unusual agitation or feeling wired. If that happens, contact your doctor promptly

What side effects should I expect?

Most are mild and settle within the first week or two as your body adjusts, and many can be eased with a counter-medicine (for nausea, for example). Not everyone gets them; the rough figures below just give a sense of how common each one is.

• Drowsiness (around 25%): mostly early on, or trouble sleeping in some people
• Nausea (around 20%): taking it after food helps, and it usually fades
• Dry mouth (around 10%)
• Constipation (around 10%)
• Headache
• Reduced appetite
• Feeling a bit more anxious or restless at first; this usually passes as the medicine starts working
• Sexual side effects

If anything is bothering you, tell your doctor; there's often a way to adjust. And if you ever feel worse instead of better, tell us straight away; it's easily managed, and that's what we're here for.

Will I become dependent? How do I stop safely?

No; duloxetine isn't addictive, but it does need a planned, gradual stop. There's no craving and no urge to take more. Your body does get used to it, though, and stopping suddenly can cause withdrawal-like symptoms in the SNRI pattern: dizziness, headache, or a "buzzing" feeling, usually starting a few days after stopping. So never stop suddenly on your own.

Tapering makes this a non-issue for most people: small steps, a week or two at each, gentler near the end, and stepping back up briefly if symptoms appear. Many people continue for some months after they feel better, and coming off is planned together.

Can I drive while taking it?

Yes, with care, especially at the start. Duloxetine can cause drowsiness or dizziness, so see how it affects you before driving, particularly when starting or changing the dose.

What about pregnancy and breastfeeding?

Often, treatment can continue through both. Neither pregnancy nor breastfeeding is an automatic reason to stop; the decision is made individually with your doctor, weighing the real risks of untreated illness. Never stop on your own on learning you're pregnant. Our guides to medication in pregnancy and medication while breastfeeding cover the details.