Page 98 - The lraternational Journal of the Royal Society of Thailand.indd

The International Journal of the Royal Society of Thailand
Volume XV-2023

be perceived. However, with repetitive application, it will lead to hyperexcitation,
mitochondrial dysfunction and degeneration of intraepidermal small nerve fiber. Therefore,
various preparations of topical capsaicin have been studied since 1980s. Capsaicin gel or
cream at the concentration of 0.075% or 8% patch may be useful and it causes almost
no systemic side effect (Kulkantrakorn et al, 2022). Local skin reaction is the major

limitation. Lower concentrations in cream and lotion were tested in randomized
controlled trial. They did not provide adequate pain relief, but the local reaction is
much tolerable (Kulkantrakorn et al, 2013; 2019). High dose patch should not be used

in insensate area, and it may impair body self-protective mechanism from pain.
A refer to neurologist or pain specialist when pain control is not achieved

within the scope of practice of the treating physician. Physician should advise their
patients that a series of medications may need to be tried to identify the treatment that
most benefits patients with PDN. Each intervention should be adequately tried to

reduce neuropathic pain. Before calling it failure, the patients should be on efficacious
dose for approximately 12 weeks is required without significant pain reduction or they
experience severe side effect.

If the initial medication does not work well or side effect is not tolerable, other
medications from a different effective class should be selected. In partial responders,

a trial of a different class as a second monotherapy or combination of different class is
recommended (Ziegler et al, 2022). However, potential drug interactions with coexisting
medication or underlying disease should be thoroughly examined. Despite widespread
use and some combination therapy trials, there is no convincing evidence to suggest
superiority of any combination over its respective monotherapies. Therefore, when

clinical should closely monitor their patient for their safety and additional benefit
(Balanaser et al, 2023).

Regarding opioid treatment, clinicians should not use strong opioids for the
treatment of PDN due to its more side effect, potential addiction, and overdose. If
patients are currently on opioids or opioids/ SNRI dual mechanism agents (such as

tramadol or tapentadol) for the treatment of PDN, clinicians may offer the option of a
safe taper off these medications and discuss alternative nonopioid treatment strategies.

In refractory case, botulinum toxin injection has been reported to be helpful,
but the procedure itself is painful and costly. Other interventions such as spinal cord
stimulation, magnetic stimulation, intrathecal pump or nerve blocks are still under

investigation regarding their efficacy and safety (Balanaser et al, 2023).

90 Revisiting Diabetic Polyneuropathy and Autonomic Neuropathy