Merck Manual

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Quick Facts

Chronic Pain


The Manual's Editorial Staff

Last full review/revision Sep 2019| Content last modified Sep 2019
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What is chronic pain?

Chronic pain is pain that lasts a long time or keeps coming back for months or years.

  • Chronic pain can happen because of a long-term disease or an injury that doesn’t heal

  • Sometimes your nervous system becomes more sensitive to pain signals than usual

  • You may have other symptoms such as feeling tired, problems sleeping, not feeling hungry, or not being interested in sex

  • You may also have emotional symptoms, such as depression, anxiety, or withdrawing from social activities

  • Doctors can treat chronic pain with medicines, physical therapy, and treatments for emotional symptoms

What causes chronic pain?

Chronic pain can be caused by an ongoing problem such as:

  • A long-lasting disorder such as cancer, arthritis, diabetes, or fibromyalgia

  • An injury that hasn't completely healed

Also, if your nerves are constantly sending pain signals, sometimes that causes long-term changes in how your nerves work. These changes can make you more sensitive to pain signals. This can make existing pain seem worse and sometimes cause pain from something that isn't usually painful.

Sometimes doctors don't know what causes someone's chronic pain.

What are the symptoms of chronic pain?

You may have other symptoms along with the pain, such as:

  • Tiredness

  • Trouble sleeping

  • Loss of appetite and weight

  • Lack of interest in sex and other activities you enjoy

  • Depression

  • Anxiety

Chronic pain can make it hard to work and do normal daily activities.

How do doctors treat chronic pain?

If doctors find a cause for your pain, they treat the cause.

Doctors also treat chronic pain using:

Behavioral therapy may help you function better, even if it doesn’t lessen your pain. It may include gradually going out more socially and doing more physical activities. It may also include asking your family or co-workers to avoid things that keep you focused on the pain, such as constantly asking about your health or insisting you shouldn't do chores.

Pain medicine

Depending on how severe your pain is, medicines may include:

  • NSAIDs—over-the-counter pain medicines, such as aspirin or ibuprofen

  • Opioids—strong painkillers available by prescription

  • Antidepressants or medicines to treat other symptoms

Your pain may vary throughout the day. Doctors may change the doses and the times you take your medicines to help with the pain.

Opioids usually treat moderate to severe pain from cancer or injuries such as a broken bone. They can have serious side effects, so your doctor may try other medicines first. If your doctor prescribes opioids, your doctor will check you often to make sure you're taking them safely. Opioids often don't work for the long term.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
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