Serotonin and norepinephrine reuptake inhibitors (SNRIs)
Selective serotonin reuptake inhibitors (SSRIs)
How It Works
Antidepressant medicines increase levels of
the chemicals produced in the brain to improve your mood. Lower doses relieve
pain and may help you sleep.
Why It Is Used
In low doses, antidepressants may relieve
chronic pain and pain related to the peripheral nervous system (neuropathic
pain), such as
cancer pain. They may also cause drowsiness, which may
improve sleep and relieve fatigue.
In higher doses,
antidepressants can help to relieve symptoms of
How Well It Works
Some people find that low doses of
antidepressants help relieve cancer pain. Researchers are still exploring
whether and how well antidepressants affect cancer pain. These drugs can
improve sleep. This, in turn, may improve your ability to manage your
Different antidepressants have different
side effects. If you have severe side effects from one drug, your doctor may
give you a different one.
Most side effects decrease over time.
They may include:
- Constipation. Make sure you drink enough fluids
while you are taking any of these drugs. Most adults should drink between 8 and
10 glasses of water or noncaffeinated beverages each day. Include fruits,
vegetables, and fiber in your diet each
- Dry mouth.
- Changes in appetite or weight.
- Nervousness or
- Blurred vision or
glaucoma that gets worse.
- Drowsiness or
- Low blood pressure.
- Tremors and
- Urinary retention.
- Decreased sex drive, impotence, or
difficulty having an orgasm.
See Drug Reference for a full list of side effects. (Drug
Reference is not available in all systems.)
FDA advisory. The U.S. Food and
Drug Administration (FDA) has issued an
advisory on antidepressant medicines and the risk of
suicide. 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.
What To Think About
Do not suddenly stop taking antidepressants. The use of antidepressants should be tapered off slowly and only under the supervision of a doctor. Abruptly stopping antidepressant medicines can cause negative side effects or a relapse into another depression episode.
Studies have found that daily use
of SSRIs may increase the risk of bone fracture in adults over age 50. Before
taking an SSRI, talk to your doctor about this risk.
is the most common antidepressant that is used to treat cancer pain. It may
cause side effects, such as dry mouth, drowsiness, constipation, or difficulty
You may start to feel better within 1 to 3 weeks of
taking antidepressant medicine. But it can take as many as 6 to 8 weeks to see
more improvement. If you have questions or concerns about your medicines, or if
you do not notice any improvement by 3 weeks, talk to your doctor.
People with cancer pain and depression are often
treated with one of the following:
- Selective serotonin reuptake inhibitor (SSRI), such as sertraline
(Zoloft), fluoxetine (Prozac), or paroxetine (Paxil)
- Serotonin and
norepinephrine reuptake inhibitor (SNRI), such as venlafaxine (Effexor) or
- Higher dosage of tricyclic antidepressant
than is used for cancer pain alone
bleeding more likely in the upper gastrointestinal tract (stomach and
esophagus). Taking SSRIs with NSAIDs (such as Aleve or Advil) makes bleeding
even more likely. Taking medicines that control acid in the stomach may
Women who take an SSRI during pregnancy have a slightly higher chance of having a baby with birth defects.
Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.
Abajo FJ, Garcia-Rodriguez LA (2008). Risk of upper
gastrointestinal tract bleeding associated with selective serotonin reuptake
inhibitors and venlafaxine therapy. Archives of General Psychiatry, 65(7): 795–803.
Primary Medical Reviewer
||E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer
||Michael Seth Rabin, MD - Medical Oncology
||October 31, 2011