Secondary Logo

Journal Logo


TENS Units in ED

Hope for the Opioid Epidemic?

Grover, Casey MD

doi: 10.1097/01.EEM.0000524784.06067.56

Dr. Groveris an emergency physician at Community Hospital of the Monterey (CA) Peninsula. He is also a physician champion of the Monterey County Prescribe Safe Initiative, a collaboration among law enforcement, hospitals, and physicians in response to prescription medication abuse. More information is available at



With the opioid epidemic raging and the pressure on emergency physicians not to prescribe as many addictive drugs, it may be time to do a little unconventional thinking when it comes to treating pain. Transcutaneous electrical nerve stimulation (TENS) therapy, an extremely useful and effective treatment for acute and chronic pain, offers a fantastic nonopioid pain management modality for ED patients.

TENS units are effective for acute and chronic pain, and work through the gate control theory. All of the stimuli to the various receptors in the body—pain, temperature, vibration, etc.—transmit signals through the ascending fibers of the spinal cord to the brain. The ascending pathways of the spinal cord cannot effectively transmit more than one type of stimulus at a time. The electrical current of a TENS unit stimulates other receptors besides the pain ones and reduce the ability of the spinal cord to transmit pain signals, closing the gates to pain. The spinal cord, basically, is being distracted by nonpainful stimuli. Chronic stimulation by a TENS unit results in an increase in endogenous opioids at the site of use, helping to treat chronic pain as well.

A TENS unit consists of three parts: a stimulus generator, wires, and electrodes. The stimulus generator is usually a battery-powered device about the size of an iPhone, which generates an electrical current. Electrodes consist of a sticker made from a conducting gel, which has the ability to connect to the wires. They are similar in appearance to cardiac monitor leads. The wires simply connect the stimulus generator to the electrodes.

Electrodes are placed around the area of greatest pain, so an electrical current passes through that area. Two electrodes may be used on either side of the area of pain for single-channel stimulus generators, and four electrodes may be used surrounding the area of greatest pain like a frame for two channel units.

Most stimulus generators have several different programs, which vary the way that the electrical stimulus is delivered. Some deliver a constant current, while others deliver current in pulses every few seconds. The stimulus generator allows the patient to determine the intensity of the current, which is usually set up like a volume control on a stereo. Turn up the intensity to get more current. What seems to work best is allowing patients to try the various programs with different pulse delivery styles and intensities to see what is most effective.

Patients may use a unit for up to 60 minutes at a time, but should monitor for any skin irritation for sessions longer than 20-30 minutes. Patients will experience a pleasant buzzing sensation at the site of the current as it relieves or reduces their pain—if electrodes are placed correctly. If patients develop muscle spasms, then the intensity should be turned down or the electrodes should be repositioned. TENS can be stopped when the pain gets better. It can be used multiple times a day for chronic pain. My wife and I like to run and exercise, so we're always using them on something that hurts.

Back to Top | Article Outline

A Cost-Effective Alternative

TENS units can be used almost anywhere on the body except for places that could result in a transcranial or transthoracic current. Patients who are pregnant should avoid applying any current near the fetus, and patients with pacemakers should not use the electrodes near their devices. Electrodes should be placed on intact skin only, not orifices such as the mouth, rectum, or genitals.

A referral to physical therapy can be helpful if your patient (or you) needs some help setting up a TENS unit. Most physical therapists are trained in their use, and can help optimize electrode placement and teach how to operate the stimulus generator. Physical therapy is no longer needed once a patient knows how to use the device, though they can follow up with PT if they have additional questions.

TENS units are relatively cheap. They vary in complexity and cost, but inexpensive units can be bought for $20-$50 without a prescription at retail pharmacies or online with vendors like Amazon. Unfortunately, most insurance companies don't pay for TENS units for acute pain, making them difficult to use in the emergency department regularly, but a physical therapy consult in the ED may be how you can get your patients treatment. Otherwise, you can recommend your patients purchase one and use it at home.

The physicians in our emergency department have been trained in how the devices work, and can assist patients with placing the electrodes and using the devices. Each patient gets a new set of electrodes, and the machine and wires are cleaned and reused like an ECG machine. Electrodes are inexpensive and available for about 60 cents for a pair, making the cost negligible for hospitals to stock them and implement a program.

We are working with local insurance companies and plans, where there is some interest in TENS. Our hope is insurance companies will start paying for TENS for treating acute pain in the ED in light of the opioid epidemic.

Share this article on Twitter and Facebook.

Access the links in EMN by reading this on our website or in our free iPad app, both available at

Comments? Write to us at

Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.