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I get a LOT of e mails with queries about various aspects of Electrotherapy, and whilst I don't know the answers to all of them, there are several themes that crop up again and again - so on this page I will try and provide some common answers to the most frequently asked questions.

I would encourage you to post questions and queries to the Electrophysical Forum which has been set up for just this purpose and will attract responses from a wide range of International experts - rather than just Tim! LINK

[Unfortunately, at the present time, the Electrophysical Forum has suffered the same fate as this website did - and is currently not up and running - but I am working on it]

The majority of the queries relate to contraindications, and the key documents in this regard are :

The Contraindications chapter in the current (2020) edition of the textbook represents a substantive volume of work. Ethne Nussbaum and I compiled the chapter, but it includes contributions from all the book authors. I am not permitted to reproduce it here (Copyright issues) but is well worth a look if you are able to access it LINK

CSP Guidance for the Use of Electrophysical Agents (Bazin, S. et al. (2006). Guidance for the Clinical use of Electrophysical Agents. London, Chartered Society of Physiotherapy, also reproduced as a chapter in Electrotherapy: Evidence Based Practice. (2008) T Watson, Elsevier).


Details can be found on the CONTRAINDICATION pages of this site.


Additionally, there was a set of Guidelines published in a special edition of the Canadian Physiotherapy Journal. I am not permitted to reproduce them here (copyright) but well worth a look if you are able to gain access : Houghton PE, Nussbaum EL, Hoens AM: Electrophysical Agents: Contraindications and Precautions. Physiotherapy Canada 2010;62(5) LINK


There was a similar paper in the Australian Journal some while back (Robertson, V. J., L. S. Chipchase, et al. (2001). Guidelines for the use of Electrophysical Agents. Victoria, Australia, Australian Physiotherapy Association) and I gather they are currrently being revisited - will post an update when it appears.


Interestingly, the UK, Canadian and Australian documents do not come up with identical lists, nor for that matter do the main textbooks - hence the controversy! Maybe one day we will be able to resolve this issue.

I will add more to the list as time goes by, but in the first instance, those identified below cover 70% plus of the contraindication queries that I would get through in a normal week. If you want fully referenced answers, go to the CSP, Canadian or Australian documents or the standard textbook chapters.

Electrotherapy and Pregnancy

This has got to be in the top 2 topics for queries. Understandably, there is a degree of concern when it comes to using electrotherapy for a patient/client who is pregnant - none of us wish to do any harm to the baby or the mother, so what do the guidelines have to say about it?

The general rule of thumb would be this : would/could the applied energy reach the foetus? and a secondary question would be : if it does, then would/could it do any harm?

If the applied energy is not reasonably expected to reach the foetus, there is little argument for it being considered a contraindication so far as I can see from the evidence. For example, applying ultrasound to the knee of a patient who is pregnant does not constitute a risk to the foetus in that the applied energy is not going to reach it and so far as we can see from the evidence, there are no systemic effects (on the mother) that would be detrimental in this circumstance. Pulsed shortwave would present a greater risk, in that the field is more extensive, and the current guidelines would suggest that if a patient is pregnant, then the application of continuous or pulsed shortwave (or microwave for that matter) to any body part is considered to be a contraindication.


The contraindications grid (available for download HERE) has 2 different contraindication categories relating to pregnancy : ANYWHERE and LOCAL. If the modality is identified as an ANYWHERE (GENERAL) contraindication, then DO NOT apply to any body part if the patient is pregnant. If a LOCAL category applies, then the general guide above applies (does the applied energy reach the foetus? and if so, could it do harm?


If in doubt, the majority of therapists take the more conservative route and refrain from applying the modality. This is fine in that the practitioner is erring on the side of caution, though it does mean that some patients are denied a potentially valuable therapy which would not actually put the baby at any risk.


The most difficult area is that of the electrical stimulation modalities, most commonly TENS and INTERFERENTIAL therapies. The CSP (2006) guidance states that TENS and other forms of electrical stimulation should not be applied to the trunk (take a zone from mid thorax down to and including hips and pelvis) during pregnancy with the exception of TENS as a means of PAIN RELIEF during labour. This has been a widely held view, but more recently, a group evaluated the evidence for the detrimental effects of TENS for back pain during pregnancy, and in fact could not identify evidence of a detrimental effect so long as the applied current was applied at a sufficiently low density. The 2007 guidance is also available from the DOWNLOAD page. There is an updated version of the TENS during Pregnancy paper (2012) but I am currently unable to access it and do not have copyright permission to post it on these web pages (though I am trying). TENS for back pain during pregnancy may not be the ideal first choice treatment, but it is NOT now considered to be an absolute contraindication as it has been in the past.


The use of TENS as a means of pain relief during labour is effective if carried out using the optimal stimulation parameters and electrode positioning. Many practitioners have 'frowned on' or advised against the mother 'practicing' with the TENS prior to labour commencing. Given the updated guidance, there is no reason why electrode positioning and machine set up can not be practiced during the latter stages of pregnancy - in fact it might be distinctly advantageous to do for optimal pain relief effects.

There has been no definitive guidance for other forms of electrical stimulation (Interferential, NMES etc), though having looked at the evidence I can't actually see that the guidance would need to be any different - though that is a personal opinion and not part of the formal guidance.




If the patient is pregnant, the modalities to completely avoid (anywhere) are shortwave, pulsed shortwave and microwave therapies.

Ultrasound and laser therapy are to be avoided locally (so that the applied energy does not reach the feotus)

Electrical stimulation modalities are generally considered best avoided in the lower trunk (mid thorax down to and including hips and pelvis) though there are additional specific guidelines with regards TENS to the trunk during pregnancy.

Electrotherapy for Children


Combined with the pregnancy issues detailed in the previous section, the issue about using various electrotherapy modalities with children is probably the other most popular query type. In fact, the general guidance would pretty much fall into the same theme :

The general rule of thumb would be this : would / could the applied energy reach the epiphysis? and a secondary question would be : if it does, then would / could it do any harm?

The concern is that if energy is applied to the active epiphysis, the it COULD have a detrimental effect on growth activity in that zone. There is a lack of experimental evidence from human / clinical research (understandably from an ethics point of view!) but there is evidence to suggest that various modalities CAN have a detrimental effect on an active epiphyseal zone, and are therefore best avoided.

This is fine, but again many therapists take an 'ultra-conservative' approach and say that the electrotherapy modalities can not be used on children - full stop! This is NOT what the guidance actually states. The energy should not be delivered such that it reaches an ACTIVE epiphyseal region. If the applied energy (ultrasound, laser, electrical stimulation) will not reach the epiphysis, then there is NOT a contraindication. If the applied energy reaches the epiphysis, but at an intensity below the detrimental effect threshold, then technically that is not a contraindication either. To refuse to apply any electrotherapy modality to any 'child' is in fact another case of denying that patient a potentially beneficial intervention.

If you want a great resource for knowing WHERE the epiphyses are and WHEN they appear and WHEN they fuse, try : The Juvenile Skeleton. L Scheuer and S Black. Pub : Elsevier, 2004 (full ref on BOOKS page).

Some modalities will 'travel' further into the tissues than others, and therefore pose an increased risk. Modalities such as ultrasound and laser travel (relatively) short distances (especially laser) and tend to be more directional, and therefore are probably amongst the 'safer' modalities to use in this regard - but even then, their use directly over an active epiphysis IS contraindicated. Modalities with a more general spread of energy through the tissues (shortwave, pulsed shortwave, microwave and the electrical stimulation therapies) are more difficult to come up with definitive guidance. My reading of the evidence out there would suggest that shortwave and microwave therapies are probably best avoided in children as it is difficult to argue that the applied energy is not going to reach an active epiphysis - then applied energy has a considerable spread in the tissues. The difficult grey area comes with the various electical stimulation modalities. There is some (limited) evidence of a detrimental effect if applied directly and at high current contrations over an active epiphysis BUT in terms of 'normal' therapy doses, applied at the skin surface, I can see no evidence of a demonstrable detrimental effect (much like in pregnancy in the previous section).

The 'official' guidance lists the electrical stimulation modalities as a 'local contraindication' in terms of the active epiphysis, and that is probably the safest way to make a judgement, though what is 'local' and how strong the applied stimulation needs to be in order to have a detrimental effect remain largely unknown.

Electrotherapy with Metal Implants

Metal implants (pins, plates, wires, nails, screws and various arthroplasities - hip and knee most commonly) are widely considered to constitute a contraindication to most, if not all electrotherapy modalities - though in fact, this is not actually the case for many.

IMPORTANT: in the context of this section, only PASSIVE IMPLANTS are considered - any implanted device which is POWERED by a battery (or equivalent) is an ACTIVE IMPLANT and should be considered to be a real contraindication to many forms of electrotherapy.


The major concern is that the applied energy will result in 'significant' heating of the metallic implant, which would have a detrimental effect in the local tissues surrounding that implant, raising the tissue temperature to damaging levels. Whist that would almost certainly be true for some modalities (most especially the high frequency heating modalities - shortwave and microwave in particular), it is not true for many others.


The contraindications grid states that the modalities that generate significant heating in the tissues SHOULD NOT be applied when there are metal implants in the tissues (Shortwave, pulsed shortwave, microwave) and the other heating modalities should be applied with caution (e.g. hotpacks). The heat modalities with the least energy penetration into the tissues (infra red and wax) are not contraindicated by metal implants. (Interestingly, Draper et al recently demonstrated that relatively high powered pulsed shortwave treatments delivered to tissue in which there was a metal implant did not actually have a detrimental effect (Draper et al 2004).

Ultrasound, when used in a PULSED (non thermal) mode is acceptable over metal as is laser therapy when used at therapy doses. Electrical stimulation modalities (TENS, Interferential, NMES etc) are not contraindicated as the amount of energy applied is not sufficient to cause a detrimental heating effect in the tissues sourrounding the implant, though the presence of metal in the tissues will almost certainly distort the pathway taken by the applied current and may therefore generate some unexpected effects in terms of sensation experienced by the patient. Passive meatal implants are NOT therefore a contraindication to the electrical stimulation modalities (ACTIVE implants are though).

Electrotherapy and Cancer


This is an enourmous topic - and I have done several presentations on it over the years. In summary, it has been widely held to be the case that electrotherapy should not be employed for patients with or with a history of cancer. The evidence does not support this ultraconservative view, and in fact the most workable guidlines follow the same principles as for pregnancy and epiphyseal regions in children (after all, the are all rapidly dividing tissues of one kind or another). The over-riding clinical decision comes down to this :


The general rule of thumb would be this : would / could the applied energy reach the cancer/tumour/metastises? and a secondary question would be : if it does, then would / could it do any harm?


There is evidence that various electrotherapy modalities can increase the rate of division/growth of malignant tissue, and one would not routinely want to expose any malignant tissue to externally applied energy. Having said that, there are many papers around out there which identify the potential use of electrotherapy as a means to reduce malignant cell growth or to 'kill' or reduce the growth rate of tumours. I would suggest that unless you are in a specialist unit, the deliberate treatment of malignant tissue with electrotherapy is best avoided.


If a patient has a history of cancer/malignancy, it does not automatically constitute a contraindication to the use of electrotherapy modalities. The key issue is one of potential benefit versus potential detrimental effect. If there is no known active malignant activity, there should not be a problem using electrotherapy.


There is some download material based on a couple of presentations that I have done on the topic available from the DOWNLOAD page if you want to chase up further details in this area.


Additionally, there is an excellent narrative review by Laakso and Young the pdf of which appears to be freely available (follow the LINK) The full reference is : Laakso, E.-L. and C. Young (2010). "Electrophysical agents (EPAs) for symptom control in cancer care–what is the evidence?" Physical Therapy Reviews 15(4): 334-343. LINK


Patients with haemophilia are not automatically contraindicated when it comes to the electrotherapy modalities - in fact there is good (anecdotal) evidence of significant benefit, especially with the use of pulsed shortwave for tissue haematomas. Recent tissue damage is listed as a contraindication for many modalities - but this is in the context of tissue bleeding - if the tissue is still bleeding following injury and a modality is applied which increases local blood flow, there will not be anything useful happening - the tissue will simply bleed more - which is clearly disadvantageous. A patient who happens to have one of the haemophilias is only at risk in the immediate post injury phase (just like everybody else) and if they use factor replacement medication, their bleeding time is almost certainly shorter than 'average'. The normal rule of thumb (all patients) is to wait till the tissue has stopped bleeding before using any electrotherapy modality - this will usually have happened by 6-8 hours. The application of pulsed shortwave earlier than this in a post trauma patient who has haemophilia is fine so long as they have used a factor replacement (Watson 2002).



This is not something that gets asked that often these days, but it has been said in the past that diabetes constitutes a contraindication to ultrasound - something for which I can't find any evidence, and I would not therefore put it on the list.


Patients with a history of epilepsy and/or focal fits have long been considered to fall into a 'precaution' category when it comes to electrotherapy. Some modalities would appear to be just fine for these patients (ultrasound, shortwave, pulsed shortwave, microwave, heat and cold treatments) but there have been several anecdotal reports and a couple of mentions in the literature of problems relating to electrical stimulation modalities (most commonly TENS, Interferential Therapy and muscle stimulation (NMES)).

The problem appears to be that SOME (certainly not all) patients when treated with electrical stimulation, most commonly up around the head, neck, shoulder girdle, get an activation of their epilepsy. There have been reports of the 'fits' occurring DURING the treatment, but also some where the fit has come on some hours later. Some of the patients have not had a fit or episode for years - all appeared to be under control.

The advice therefore is that if the patient has current epileptic episodes or has a history of epilepsy (in any form), one would want to be extremely cautious with the application of electrical stimulation, and most especially when used in the head, neck or shoulder girdle region. I am aware of at least one anecdotal report of a patient with quiescent epilepsy having been treated with electrical stimulation for pain relief, low back, having an episode during the treatment - so it is not exclusive to the upper quadrant.

If you do want to use electrical stimulation for these patients, it is not an absolute contraindication, but careful attention needs to be paid to the potential adverse effects and the patient needs to make a clearly informed choice - knowing the potential risks.


In summary, the more 'active' the epilepsy, the greater the risk. The closer the stimulation zone is to the head, neck and shoulder girdle, the greater the risk. Even with stimulation away from this area in patients with a 'quiescent' epilepsy, there would appear to be a risk of initiating an episode, and strong caution therefore needs to be taken. If in doubt, best to consult with the neuro team (or whoever) is looking after the patient in this regard.



Warfarin and other anticoagulant medications are frequently cited as being a contraindication to the use of most, if not all electrotherapy modalities. One looking through the literature, I can't actually see much, if anything that would constitute an increased risk except following a RECENT injury, when tissue bleeding will be going on (first hours) in which case, the medication will almost certainly increase the duration of the bleed, and therefore, you should leave it longer before starting the electrotherapy modality - you want the bleeding to have stopped before doing ultrasound or pulsed shortwave or laser for example.

The only other obvious increased risk would be the application of any electrical stimulation modality (usually Interferential therapy) using the VACUUM electrode system. The electrical stimulation itself is NOT the contraindication - it is the VACUUM ELECTRODES which are the problem (tissue trauma and increased risk of tissue damage and bleeding). If this is the case, then the application of the electrical stimulation modality using pad or pre-gelled self adhesive electrodes would be fine and is NOT contraindicated.


If in doubt, then best to contact the medical practitioner who is looking after the patient in this regard and consider the stability of the warfarin (or whatever medication) dose and the stability of the clotting time (INR). There is clearly a greater risk if the drug dose has not yet been stabilised or if the clotting times are unstable.


The issue with pacemekers is a matter of whether the applied energy will have any effect on the implanted pacemaker, and if so, would it be detrimental to the patient? The main problem here is that different pacemakers appear to behave differently to others - some are susceptible to the applied energy and others are not. Most therapists are not aware of WHICH pacemaker type their patient has, and even less aware of which ones are a problem and which ones not HENCE the guidelines here and in other documentation, tends to take a CONSERVATIVE view - which is clearly the safest route.

Some modalities are best COMPLETELY AVOIDED

Shortwave / Pulsed Shortwave and Microwave / Pulsed Microwave all have the potential to interfere with an implanted pacemaker, so it is best not to treat the patient at all with these modalities - not even in a region distant from the trunk. The best guidance that I can find is that a patient with a pacemaker should not be nearer than 3 metres from an operating machine of this type. I suspect that the majority of modern pacemakers would actually be fine a whole lot closer than that BUT until we have some more definitive evidence, stick to the 3 metre rule and you will be fine.

Electrical stimulation modalities (this would include ANY electrical stim delivered through surface or implanted electrodes - like TENS, Interferential, muscle stimulation, Russian currents, H wave and a whole host of others) are best avoided anywhere on the patient. The delivery of an electrical current from an external source has the potential to cause interference with the operation of the pacemaker and whilst some pacemakers are fine, others are not, and there have been reports in the literature of interference and problems (there are other reports in the literature showing no problems).

It is argued that applying TENS to the low back (for example) is far enough away not to be a problem BUT given that this is not yet established, the safest thing is to NOT USE ANY ELECTRICAL STIMULATION for ANY patient with a pacemaker fitted.

Modalities where there is NOT EXPECTED to be a problem or where the restrictions are LOCAL :

ULTRASOUND is OK to use on a patient with a pacemaker so long as the applied energy does not reach the implanted device, leads, battery etc. 
LASER THERAPY - there is no known reason why laser should be contraindicated as the applied energy is not expected to have any interaction with the implanted device. 

Anti Coagulants
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