Side Effects and Contraindications of Electrotherapy
If you plan to use or receive electrotherapy, it is important to be aware that although this therapeutic method can be extremely useful in many cases, it can also have contraindications. Electrotherapy uses different types of electrical currents to achieve specific medical, rehabilitative or cosmetic goals, but in many situations it may be contraindicated for you. Let’s look in detail at when you should be particularly cautious or avoid this treatment completely.
What is electrotherapy?
Electrotherapy is not a single method or treatment, but a very diverse group of approaches. Individual methods differ in the type of current used and therefore produce different effects. For example, TENS, MENS and interferential currents are effective for pain relief; EMS and Kotz currents help improve muscle condition; microcurrent and interferential treatments can be used to promote tissue healing. Before treatment, it is important to be familiar with the contraindications to avoid possible risks.
The latest research and updated guidelines can help you better understand when electrotherapy is not recommended.
Physiotherapy treatments using electrical currents
Physiotherapy treatments using electrical currents offer many benefits and can be applied to various health problems. Electrotherapy uses different types of electrical currents that elicit specific effects in the body. These treatments can help reduce pain, increase blood circulation, improve muscle function, and promote tissue healing.
One of the best-known forms is TENS treatment, which is used to reduce musculoskeletal pain. Also included are selective denervated current treatments that help improve the condition of muscles affected by motor nerve damage (paralysed muscles). During electrical stimulation treatments, the electrical current affects the body at different frequencies and intensities, producing various physiological responses.
Electrical treatments are not only suitable for pain relief and promoting healing, but also for rehabilitation and improving athletic performance. The techniques and devices used in electrotherapy are continuously evolving, enabling personalized and effective treatment solutions.
Types of electrotherapy treatments
Electrotherapy treatments use many different types of electrical currents, each with specific effects. Below we present the most commonly used electrotherapy treatments and their main characteristics.
Low-frequency treatments use electrical currents of low frequency that penetrate deeply into tissues and trigger various physiological effects. These treatments are particularly effective in reducing muscle pain, muscle cramps, and chronic pain.
The following are among the (home-applicable) electrical treatments: TENS (pain relief), EMS or NMES (muscle treatment), MENS (microcurrent pain relief), MCR (anti-inflammatory microcurrent), iontophoresis (local delivery of active agents), interferential (pain and anti-inflammatory), Kotz (also known as Russian, muscle-strengthening treatment), FES (functional electrical stimulation), CES (cranial electrostimulation), TES (threshold stimulation for muscle treatment), tVNS (vagus stimulation).
Product recommendation: our range of electrotherapy devices
Electrotherapy is an umbrella term. It includes every treatment method that uses electrical currents.
The best-known electrotherapy method: TENS
Most people probably recognise the term TENS (Transcutaneous Electric Nerve Stimulation). It is one of the oldest electrotherapy methods. It began to be used for pain relief in the early 1970s. The theoretical basis behind the procedure was provided by the Melzack–Wall gate control theory published in 1965, which showed that stimulating nerves can block pain impulses from reaching the brain and can promote the release of endorphins.
So although the development of TENS devices only started in the 1970s, the scientific foundation of the method is the discovery and theory developed by Ronald Melzack and Patrick Wall.
TENS is therefore the first, but not the only, electrotherapy method.
TENS uses electrical stimulation through the skin to reduce pain. During TENS treatment, electrical stimulation reduces pain, increases blood circulation, and improves the condition of the treated area.
TENS is particularly effective in reducing chronic pain, muscle pain, and inflammatory pain. The electrical stimulation used in the treatment activates the body’s natural pain-relief mechanisms and reduces pain perception.
TENS has many advantages, including fast and effective pain relief, minimal side effects, and ease of use. A typical TENS session lasts 15–30 minutes, during which the electrical stimulation enhances blood circulation and improves the condition of the treated area.
TENS devices used for treatment are generally small, portable devices that provide electrical stimulation. Devices usually offer multiple programs that can be adapted to different types of pain and treatment objectives.
Overall, TENS is an effective and safe electrotherapy method suitable for pain relief and improving the condition of the treated area. Its ease of use and minimal side effects have made it increasingly popular in pain management.
General contraindications
Cardiovascular conditions
If you have a pacemaker or an implantable cardioverter-defibrillator (ICD), special caution is required.
Until recent years, the conventional approach completely prohibited electrotherapy. However, recent research suggests a more nuanced approach may be possible. Modern cardiac devices have improved protection against electromagnetic interference, which potentially allows certain forms of electrotherapy to be applied if they are performed at a sufficient distance from the device. Nevertheless, every application requires careful consideration and consultation with a cardiologist.
For patients with arrhythmia or ischemic heart disease, concerns focus on the potential effects of electrical currents on cardiac conduction.
A 2022 study showed that carefully performed electrotherapy applications are safer than previously thought, especially when treating peripheral areas (distant from the heart and neck).
However, direct treatment over the chest remains strictly contraindicated. The key is to maintain an appropriate distance from the heart and to use proper current parameters.
Pregnancy
Pregnancy requires special considerations when applying electrotherapy. The primary concern is the potential effect of electrical currents on the developing fetus and the risk of inducing preterm labor. Current research emphasises avoiding electrotherapy applications over the abdomen, pelvis and lower back throughout the entire pregnancy.
Risks during pregnancy vary depending on gestational stage. In early pregnancy, electrical stimulation could disrupt implantation and early placental development.
In later stages, concerns shift to the possibility of inducing uterine contractions and effects on fetal development.
Some studies indicate that carefully controlled electrotherapy may be safe when applied to areas remote from the abdomen/uterus for pain relief. In my recommendation, such applications should only be performed with explicit medical approval.
Active cancers or malignant lesions
Electrotherapy is contraindicated over and in close proximity to active cancer and malignant lesions.
The primary concern is that electrical stimulation may increase cellular activity and blood flow, which could theoretically promote the growth or spread of cancer cells. This contraindication extends beyond active cancer to suspected malignant lesions and recent cancer treatments.
Recent studies are beginning to investigate whether certain low-intensity electrotherapy modalities may be safe for cancer patients, especially for palliative care (cancer pain relief). Treating areas distant from the tumor may also be considered, where no direct effect on the tumor is expected.
However, any such application requires careful consideration of the cancer type, stage and overall treatment plan. Consultation with an oncologist is essential before considering any electrotherapy in patients with current or recent cancer.
Epilepsy
Neurological conditions, particularly epilepsy, require careful consideration before applying electrotherapy.
The main concern with epilepsy is the potential of electrical stimulation to trigger seizures, especially when applied near the head or neck. Current research continues to support this caution, particularly regarding cranial electrostimulation.
The contraindication goes beyond avoiding direct cranial application.
In patients with epilepsy, even peripheral (distant from the skull) electrotherapy applications require careful assessment, because neural stimulation can provoke seizure activity via neural pathways.
An individual risk assessment and consultation with a neurologist are essential in cases of epilepsy.
Acute infections
The presence of acute infections, local or systemic, is a significant contraindication for electrotherapy.
The main concern is that electrical stimulation may increase blood flow and potentially spread the infection. This applies to bacterial and viral infections as well as fungal conditions.
Recent research highlights the possible interactions between electrical stimulation and the immune response.
While increased circulation stimulated by electrotherapy can aid healing in conditions such as arthritis, in the presence of active infection the improved circulation could disseminate the infection and worsen the condition. This is especially important in systemic infections like sepsis, where the body’s resources are already heavily taxed.
Uncontrolled hypertension or hypotension
Blood pressure stability plays an important role in determining the safety of electrotherapy applications. Patients with uncontrolled (fluctuating despite treatment) hypertension or hypotension may be at risk from electrical stimulation because it affects the autonomic nervous system and thus blood pressure regulation.
This contraindication is particularly relevant in situations where electrical stimulation may cause sudden blood pressure changes via vasodilation or autonomic effects.
Recent research suggests monitoring blood pressure during treatment (measure 1–2 times during a session) in patients with treated hypertension, especially during initial sessions.
Bleeding disorders or use of anticoagulants
Patients with bleeding disorders or who take anticoagulant medications require consideration when contemplating electrotherapy.
Increased blood flow and vasodilation associated with electrical stimulation may potentially cause bleeding or bruising in these patients.
This contraindication is particularly relevant in areas where blood vessels are close to the surface or in regions prone to bleeding.
Risk assessment should take into account both the type of bleeding disorder and the specific anticoagulant medication, as different agents carry different risk levels.
Cognitive impairments
If you have cognitive impairment—for example you have difficulty understanding instructions or cannot provide accurate feedback during treatment—electrostimulation is not recommended because it increases the risk of injury.
Local contraindications
Treatment over implanted metal devices
The presence of metal implants has traditionally been considered a contraindication for electrotherapy, especially directly over the implant. However, modern research is beginning to question some of these assumptions, particularly with newer implant materials and designs.
Current interpretation is that while direct application over metal implants should still generally be avoided, the presence of an implant does not automatically preclude electrotherapy on other parts of the body, especially at a distance of around 10–15 cm from the metal. For example, treating the knee joint over a knee prosthesis is not recommended, but treating the thigh or calf muscles is not contraindicated.
The decision depends on implant type, location and the electrotherapy modality to be used. Titanium implants, for example, may require different considerations than older steel implants.
Area of thrombosis or thrombophlebitis
If there is a fresh blood clot in your body, electrotherapy could dislodge it and cause life-threatening complications such as stroke or pulmonary embolism. Do not use electrotherapy over such areas.
About three months after a thrombosis, a state usually develops in which electrical treatment no longer affects the clot, and electrotherapy can be used thereafter (in fact, it can be one symptomatic therapeutic option in the post-thrombosis period).
Stimulation over sensitive areas
Do not apply current to the eyeball or eyelids, as it can damage sensitive tissues. Avoid the neck area (carotid sinus), because electrical stimulation here can cause fainting or cardiac arrest. The genital area is particularly sensitive and is generally not suitable for most electrotherapy treatments.
Over open wounds or damaged skin
The condition of the skin and underlying tissues plays a key role in determining the safety of electrotherapy.
Open wounds, damaged skin or areas with compromised tissue integrity pose specific contraindications due to the risk of infection, tissue damage or altered current flow. Applying electrical stimulation in such cases requires particular caution.
Recent research is exploring electrotherapy applications specialised for wound healing, but these require specific protocols and equipment. Standard electrotherapy applications remain contraindicated over actively damaged tissues.
Areas with sensory impairment
Areas with reduced sensation present unique challenges and contraindications for electrotherapy.
The inability to accurately report the sensation of electrical stimulation can lead to tissue damage or burns, particularly in patients with conditions such as peripheral neuropathy or spinal cord injury.
This contraindication requires careful sensory assessment before starting treatment and may necessitate modified protocols or alternative approaches for the affected areas. Regular monitoring and re-evaluation are essential components of safe application.
If you have reduced sensation in an area, be especially cautious. You may not feel stimulation adequately and could set the intensity too high, causing burns. In such cases, avoid increasing the intensity too much.
Cosmetic contraindications
If you plan to use electrotherapy for cosmetic purposes, such as facial treatments or body shaping, consider the following:
Do not apply electrotherapy over eczema, psoriasis or acne, as the current may irritate inflamed skin. If you have recently had Botox or fillers, wait at least 2–4 weeks, because electrical currents could displace or degrade these treatments. If you have had recent surgery, wait until full healing before applying electrotherapy near the treated area. Electrical stimulation should also be avoided in these situations.
Whole-body electrical stimulation (WB-EMS)
Forms of electrical stimulation such as WB-EMS (whole-body electrostimulation, also known as EMS muscle training) are becoming increasingly popular in training and rehabilitation.
If you plan to use whole-body EMS, pay attention to the following:
If you have diabetes, hypertension or a stable cardiovascular condition, WB-EMS can be used safely under strict protocols.
Do not use WB-EMS if you have advanced atherosclerosis, as unstable plaques may lead to complications.
Do not perform too many EMS sessions in a short period, as this can cause muscle tissue damage (rhabdomyolysis). Always seek professional guidance.
Age-specific considerations
Electrotherapy is generally not recommended for children because their nervous systems are still developing. It should only be used for clear medical indications and with specialist approval. Electrical stimulation requires particular caution in this age group.
If you are elderly, pay attention to your skin condition and comorbidities, as electrotherapy may carry greater risks. Treatments should be performed cautiously, conservatively and under close supervision.
Practical application and risk assessment
Applying these contraindications in practice requires careful individual assessment and consideration of multiple factors. The use of electrical stimulation demands particular attention.
This includes:
- Understanding the specific electrotherapy modality to be applied and its particular risks and contraindications.
- Evaluating the patient’s full medical history and current condition.
- Considering interactions between multiple coexisting conditions or risk factors.
- Maintaining regular monitoring and assessment throughout the entire treatment process.
Recommendation
For safe and effective electrotherapy, you must know and consider all contraindications thoroughly. In some cases you must avoid the treatment entirely; in others it can be used safely with appropriate precautions. The key to safe treatment is thorough investigation, adherence to appropriate precautions and regular monitoring of your condition. Electrical stimulation itself can also be one of these precautions.
Modern research continuously provides new information about contraindications, allowing safer and more personalised treatment applications. However, the basic principle remains unchanged: your safety must always come first when applying electrotherapy.
A thorough understanding of electrotherapy contraindications helps you and your treating physician make informed decisions about treatment options, ensuring optimal outcomes while minimising risks.
As research continues and technology advances, new possibilities for safe and effective treatments are expected to emerge.
The field of electrotherapy is constantly evolving, with new treatment methods and applications regularly appearing.
This means you should always seek up-to-date information about contraindications and safety guidelines. With careful consideration of contraindications and appropriate risk assessment, electrotherapy can be a valuable therapeutic tool for you in modern healthcare and rehabilitation.
Latest research and updated guidelines
Some previous contraindications, such as diabetes or cancer, may be re-evaluated under strictly controlled conditions.
Modern (latest) pacemakers and defibrillators better withstand electromagnetic interference, which allows electrotherapy to be performed even in the presence of these devices. New research indicates that electrical stimulation has become safer with these devices.
Stimulation near the head and neck still remains high-risk for people with epilepsy.
For professionals, I recommend the following English-language publications on the subject.
- researchgate.net/publication/321535620_The_safety_of_electrical_stimulation
- pubmed.ncbi.nlm.nih.gov/2136990/
- heart.org/en/health-topics/arrhythmia/prevention–treatment-of-arrhythmia
- physio-pedia.com/Transcutaneous_Electrical_Nerve_Stimulation_(TENS)
- heart.org/en/health-topics/arrhythmia/prevention–treatment-of-arrhythmia/
