EUROPEAN PAIN MANAGEMENT DISCUSSION FORUM

ABSTRACT

Queries from European physicians about analgesic pharmacotherapy and responses from the author are presented. The topics addressed in this issue are the potential effect of nonsteroidal anti-inflammatory drugs on bone fractures, use of topical analgesics for osteoarthritis pain in a patient who is nonadherent with oral pharmacotherapy, and the use of transcutaneous nerve stimulation for cancer pain management.

KEYWORDS. :

• adherence
• cancer pain
• compliance
• coxibs
• fracture
• nonsteroidal anti-inflammatory drugs
• NSAIDs
• osteoarthritis
• TENS
• topical
• transcutaneous electrical nerve stimulation

QUESTION

Can I provide effective pain relief from osteoarthritis of the hand in a 73-year-old woman, who does not comply well with oral analgesia, by using transdermal preparations?

ANSWER

This question raises the significant issue of compliance of patients with chronic pain to medical treatment in general, and to the use of oral analgesic medications specifically. In my experience, noncompliance is particularly common among elderly patients who already use a large number of medications for other conditions, and even more so if they experience localized pain (in one hand or one joint only). These patients, like the woman described in the question, are often reluctant to take additional pills. It has long been known that transdermal drug delivery provides the advantage of maintaining constant drug plasma levels and improved patient compliance.¹ However, it should be remembered that transdermal preparations vary considerably in many ways, and these must all be taken into consideration. Not all patches are effective for all types of pain. Lidocaine patches are indicated for localized neuropathic pain, NSAID patches for localized inflammatory pain, and opioid patches for all types of either localized or diffuse moderate to severe pain. Patches have differing durations of analgesia.

Lidocaine and NSAID preparations have to be replaced twice daily. Opioid patches deliver rugs for longer periods and are changed twice weekly or every 7 days, depending on the opioid and preparation. Whereas lidocaine and NSAID preparations have relatively good safety profiles, transdermal opioid patches have the potential to cause typical opioid-induced adverse effects. Hence, transdermal preparations can be offered to some people who exhibit a low level of compliance, but should be individually adjusted to the patient and the type of pain they have.

QUESTION

Can transcutaneous electrical nerve stimulation (TENS) be used safely for the management of cancer pain?

ANSWER

While considering using TENS for cancer pain management, two questions should be answered: Is the treatment effective? Is it safe? Regarding efficacy, a systematic review found only two randomized controlled trials (RCTs) with only 64 patients involved.¹ In one RCT, there were no significant differences between TENS and placebo in women with chronic pain secondary to breast cancer treatment. In the other RCT, there were no significant differences between acupuncture-like TENS and sham TENS in palliative care patients. The studies were heterogeneous in many ways and a formal meta-analysis could not be performed, but the reviewer concluded that the “results… are inconclusive due to a lack of suitable RCTs.”¹ Sporadic case reports, however, show that TENS can be applied successfully (for example in a patient with cancer bone pain²).

As far as safety is concerned, there are no clinical data to suggest that TENS treatment can enhance tumor growth or metastatic spread. On the contrary, preliminary new studies suggest that low intensity alternating electric fields can slow or even arrest tumor growth, possibly by decreasing tumor angiogenesis.³ Thus, clinicians’ fear of enhanced tumor growth or metastatic spread as a result of TENS treatment does not seem to have any scientific background.