Examples

How It Works

SNRIs work to increase the activity of brain chemicals called serotonin and norepinephrine. Doctors do not know exactly how this improves fibromyalgia symptoms.

Why It Is Used

Doctors may prescribe serotonin and norepinephrine reuptake inhibitors (SNRIs) when mood problems are a major symptom of fibromyalgia. SNRIs are also used for people without fibromyalgia who have depression.

How Well It Works

Some people with fibromyalgia who take SNRIs notice an improvement in a number of symptoms, including depression, pain, and fatigue.¹

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

• Usually the benefits of the medicine are more important than any minor side effects.
• Side effects may go away after you take the medicine for a while.
• If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call 911 or other emergency services right away if you have:

• Trouble breathing.
• Hives.
• Swelling of your face, lips, tongue, or throat.

Venlafaxine

Call your doctor right away if you have:

• Thoughts of suicide.
• Agitation and restlessness.
• Seizures.
• Blurry vision.
• Headache.

Duloxetine

Call your doctor right away if you have:

• Thoughts of suicide.
• Agitation and restlessness.
• Dark urine or light-colored stool.
• Nausea and vomiting.
• Yellow eyes and skin (jaundice).
• Upper right abdominal pain.

Common side effects of these medicines include:

• Constipation.
• Cough.
• Decrease in sexual desire or ability.
• Dizziness.
• Dry mouth.
• Increased sweating.
• Headache.
• Nausea and loss of appetite.
• Sleep problems.
• Weight loss.

FDA advisories. The U.S. Food and Drug Administration (FDA) has issued:

• An advisory on antidepressant medicines and the risk of suicide in children and adults. The FDA does not recommend that people stop using these medicines. Instead, a person taking antidepressants should be watched for warning signs of suicide. This is especially important at the beginning of treatment or when doses are changed.
• A warning about taking triptans, used for headaches, with SSRIs (selective serotonin reuptake inhibitors) or SNRIs (selective serotonin/norepinephrine reuptake inhibitors). Taking these medicines together can cause a very rare but serious condition called serotonin syndrome.