• Weil Nutrition Corner
  • Meet Dr. Weil
  • Origins
  • Healthy Aging
  • Marketplace
  • Podcasts
  • Accessibility
  • Subscribe
Dr. Weil Logo Dr. Weil Logo Weil™ Andrew Weil, M.D.
  • Health & Wellness
    Health & Wellness
    Body, Mind & Spirit
    • Addiction
    • Allergy & Asthma
    • Autoimmune Disorders
    • Back Pain
    • Bone & Joint
    • Cancer
    • Colds & Flu
    • Dental & Oral
    • Diabetes
    • Disease & Disorders
    • Ears, Nose, & Throat
    • Feet
    • Gastrointestinal
    • Hair, Skin, & Nails
    • Headache
    • Heart
    • Insects & Parasites
    • Liver & Kidney
    • Mental Health
    • Pregnancy & Fertility
    • Respiratory
    • Sexual Health
    • Sleep Issues
    • Stress & Anxiety
    • Vision
    Balanced Living
    • Exercise & Fitness
    • Gardening
    • Healthy Home
    • Healthy Living
    • Meditation & Inspiration
    • Meet Dr. Weil
    • Pets & Pet Care
    • Technology
    • Wellness Therapies
    Health Centers
    • Aging Gracefully
    • Children
    • Condition Care Guide
    • Men
    • Women
  • Diet & Nutrition
    Diet & Nutrition
    Anti-Inflammatory Diet & Pyramid
    Cooking & Cookware
    Diets & Weight Loss
    Food Safety
    Nutrition
    Recipes
  • Vitamins, Supplements & Herbs
    Vitamins, Supplements & Herbs
    Herbs
    Supplements & Remedies
    Vitamins
  • Ask Dr. Weil
  • Blogs
    Blogs
    Bulletins
    Health Tips
    Spontaneous Happiness
  • Mushrooms
  • Sleep
Press "Enter" to search
Dr. Weil Logo Weil™ Andrew Weil, M.D.
  • Health & Wellness
    Health & Wellness
    Body, Mind & Spirit
    • Addiction
    • Allergy & Asthma
    • Autoimmune Disorders
    • Back Pain
    • Bone & Joint
    • Cancer
    • Colds & Flu
    • Dental & Oral
    • Diabetes
    • Disease & Disorders
    • Ears, Nose, & Throat
    • Feet
    • Gastrointestinal
    • Hair, Skin, & Nails
    • Headache
    • Heart
    • Insects & Parasites
    • Liver & Kidney
    • Mental Health
    • Pregnancy & Fertility
    • Respiratory
    • Sexual Health
    • Sleep Issues
    • Stress & Anxiety
    • Vision
    Balanced Living
    • Exercise & Fitness
    • Gardening
    • Healthy Home
    • Healthy Living
    • Meditation & Inspiration
    • Meet Dr. Weil
    • Pets & Pet Care
    • Technology
    • Wellness Therapies
    Health Centers
    • Aging Gracefully
    • Children
    • Condition Care Guide
    • Men
    • Women
  • Diet & Nutrition
    Diet & Nutrition
    Anti-Inflammatory Diet & Pyramid
    Cooking & Cookware
    Diets & Weight Loss
    Food Safety
    Nutrition
    Recipes
  • Vitamins, Supplements & Herbs
    Vitamins, Supplements & Herbs
    Herbs
    Supplements & Remedies
    Vitamins
  • Ask Dr. Weil
  • Blogs
    Blogs
    Bulletins
    Health Tips
    Spontaneous Happiness
  • Mushrooms
  • Sleep
  • Weil Nutrition Corner
  • Meet Dr. Weil
  • Origins
  • Healthy Aging
  • Marketplace
  • Podcasts
  • Accessibility
  1. Home
  2. Health & Wellness
  3. Body, Mind & Spirit
  4. Cancer

Do Painkillers Cause Cancer Spread?

I just heard that painkillers such as morphine can cause the spread of cancer? True? If so, why are these drugs so widely used for cancer pain?

Andrew Weil, M.D. | August 3, 2010

do painkillers cause cancer spread
1 min

The short answer to your question is that we don’t know for sure. Some recent research does suggest that morphine, the drug most often used to ease pain in cancer patients, can promote the spread of the disease. An article in the June 25, 2010 issue of Scientific American reported on animal studies showing that morphine can promote breast cancer by making cells replicate faster and speeding the development of new blood vessels needed by tumors to grow.

Investigators have suggested that certain receptors (called mu-opioid receptors) on cell membranes that bind to pain-killing opioids are involved. Animals lacking these receptors don’t develop cancer when injected with cancer cells, and also blocking these mu-opioid receptors in mice (with other drugs) inhibits cancer spread.

The Scientific American article also discussed the possibility that the type of anesthesia used in cancer surgery could play a role in the spread of the disease. Some preliminary research suggests that patients who get general anesthesia need more pain-killing opioids afterward compared to those who get a combination of a general anesthetic plus “regional anesthesia” or nerve blocks.

Here’s the rationale for that: some cancer cells inevitably are left behind after surgery. If the immune system is able to deal with them, there’s less chance of a recurrence. But the stress of surgery plus the use of pain-killing opioids afterward might reduce the ability of the immune system’s natural killer cells to search for and destroy wayward cancer cells. This stress may be less when regional anesthesia is used. A study published in 2006 by researchers in Ireland and the United States showed that breast and prostate cancer patients who received regional anesthesia were less prone to recurrence of the disease. Two ongoing clinical trials are looking into this, but we won’t know the outcome for at least three years. We also need to know much more about how morphine might affect cancer recurrence in humans.

Andrew Weil, M.D.

Advertisement
Related Weil Products

Dr. Weil on Healthy Aging for Cancer Support

Dr. Weil on Healthy Aging – Do you or a loved one have cancer? The Dr. Weil on Healthy Aging online guide has simple, effective preventive health information and tools including an exclusive version of Dr. Weil’s Anti-Inflammatory Food Pyramid. Join today and get 14 days free!
Get Started
Dr. Weil on Healthy Aging

Start Your 14-Day Free Trial

Free Newsletters

Stay Connected With Dr. Weil

Anti-Inflammatory Diet

Follow Dr. Weil’s Food Pyramid

Get Dr Weils Newsletter Updates

Exclusive Lifestyle, Nutrition & Health Advice

Dr. Weil's FREE health living advice delivered to you!

By clicking "Subscribe," you agree to the DrWeil.com Terms and Conditions and Privacy Policy. You also agree to receive emails from DrWeil.com, and you may opt out of DrWeil.com subscriptions at any time.

Trending Now

3-d mammograms
Cancer

3-D Mammograms?

a better test for breast cancer
Cancer

A Better Test For Breast Cancer?

HDL Cholesterol & LDL Cholesterol: What They Mean | Heart Health | Andrew Weil, M.D.
Cancer

A Blood Test for Breast Cancer?

a test for ovarian cancer
Cancer

A Test for Ovarian Cancer?

Dr. Weil Logo Weil™ Andrew Weil, M.D.
Dr. Weil's Signature

Exclusive Lifestyle, Nutrition & Health Advice

  • About Us
  • Press Information
  • Advertising
  • Contact Us
  • Terms of Use
  • Privacy Policy
  • Accessibility

Terms of Use | Privacy Policy

Information on this website is provided for informational purposes only and is not intended as a substitute for the advice provided by your physician or other healthcare professional. You should not use the information on this website for diagnosing or treating a health problem or disease, or prescribing any medication or other treatment. Any third party offering or advertising on this website does not constitute an endorsement by Andrew Weil, M.D. or Healthy Lifestyle Brands.

© Copyright 2025 Healthy Lifestyle Brands, LLC. All rights reserved. Reproduction in whole or in part without permission is prohibited. www.drweil.com