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What Is Substance P?

How Is Substance P Associated With Arthritis Pain?


Updated April 28, 2014

Question: What Is Substance P?

What is Substance P? Where is Substance P found in the body? How is Substance P related to arthritis and arthritis pain?


Nerve cells communicate with one another through neurotransmitters. Substance P is one such neurotransmitter. It is a protein found in the brain and spinal cord and it is associated with some inflammatory processes in the joints. Its function is to cause pain. Substance P has been implicated in pain syndromes, such as:

Research has considered a more intricate and expanded role for Substance P. Evidence about the role of Substance P has evolved since it was first discovered around 1931. Substance P is now believed to be involved in the integration of pain, stress, and anxiety.

Substance P also is involved in other physiologic activities:

  • the vomiting reflex
  • defensive behavior
  • change in cardiovascular tone
  • stimulation of salivary secretion
  • smooth muscle contraction
  • vasodilation

Decreasing the Effect of Substance P on Pain

Research investigating Substance P may lead to new drugs and treatments. As it is now, over-the-counter creams comprised of capsaicin (made from chili peppers) are felt to help deplete substance P from local nerve endings and relieve pain.

According to rheumatologist, Scott J. Zashin, M.D., "It may take 1 to 4 weeks to work. The capsaicin cream will often burn or sting, which will typically resolve during the first week of treatment but may last longer. Once pain relief has occurred, treatment must continue to maintain benefit until the problem no longer persists."

Contact with eyes may be irritating so always wash your hands if capsaicin cream touches them. If you are applying the capsaicin medication due to hand pain, leave it on for 30 minutes before washing.


Scott J. Zashin, M.D., clinical assistant professor at University of Texas Southwestern Medical School, Division of Rheumatology, in Dallas.

Substance P: A New Era, a New Role, Pharmacotherapy, C. Lindsay DeVane, Pharm.D.

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