How Do Topical TRPV1 Agonists Work?

Topical TRPV1 agonists (transient receptor potential cation channel subfamily V member 1) are a class of drugs used to treat minor aches and pains of the muscles and joints caused by sprains, strains, arthritis, bruises, cramps, and neuralgias. Neuralgia is a shooting or burning pain that comes from the nerves near the surface of your skin.

TRPV1 is a cation (a positively charged ion) that is activated by various exogenous and endogenous physical and chemical stimuli (high temperature, acidic conditions, and capsaicin). The activation of TRPV1 leads to a painful, burning sensation. TRPV1 agonists (capsaicin) are an active ingredient in chili peppers which make them hot.

Topical TRPV1 agonists work in the following ways:

• TRPV1 receptor is useful to measure how an organism can sense temperature change.
• TRPV1 agonists upon prolonged application cause TRPV1 activity to decrease (a process called desensitization), leading to alleviation of pain initially and then subsequent decrease in the pain.
• They also help in decreasing certain natural substances (substance P) in our body responsible for passing the pain signals to the brain.
• They help block pain messages to the nerves by decreasing the nerve cell activity, thus reducing the perception of pain.

Topical TRPV1 agonists are available in the form of creams, lotions, and gels.

TRPV1 agonists are used in conditions such as:

• Minor aches/pains caused by:
  • Sprains
  • Strains
  • Bruises
  • Cramps
  • Arthritis (inflammation of the joints)
  • Backaches
  • Rheumatoid arthritis (a chronic inflammatory disorder affecting many joints, including those in the hands and feet)
  • Osteoarthritis (a degenerative disease that worsens over time, often resulting in chronic pain)
• Diabetic peripheral neuropathy (nerve damage caused by chronically high blood sugar)
• Skeletomuscular pain (pain in the muscles, bones, ligaments, tendons, and nerves)
• Painful HIV-associated neuropathy (numbness and pain in hands and feet)
• Erythromelalgia (a rare condition that causes episodes of burning pain in the extremities)
• Fibromyalgia (a chronic rheumatic condition that causes widespread pain throughout the body)
• Postherpetic neuralgia (a painful condition that affects the nerve fibers and skin)
• Pain due to shingles (a viral infection that causes a painful rash)
• Migraine (severe throbbing pain or a pulsing sensation, usually on one side of the head)

TRPV1 agonists can make your skin sensitive to the sun, so make sure you use sunscreen before going outdoors. Do not use them on open wounds or on sunburned, dry, chapped, or irritated skin.

Common side effects include:

• Erythema (redness) at the application site
• Pain at the application site
• Nausea
• Vomiting
• Skin irritation
• Dryness
• Pruritis (itching)
• Burning and/or stinging

Other rare side effects include:

• Headache
• Exfoliation
• Dysgeusia (a taste disorder that causes foul, rancid, metallic, or salty taste perception)
• High blood pressure
• Anaphylaxis
  • Rash
  • Hives
  • Itching/swelling
  • Dizziness (feeling faint, weak, or unsteady)
  • Trouble breathing

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Drug names include:                              

• Axsain
• Capsaicin topical
• Capzasin P
• Capzasin-HP
• Menthac
• No Pain-HP
• Pain Doctor
• Pain-X
• Rid-A-Pain
• Salonpas Hot
• Trixaicin
• Zostrix