Send to

Choose Destination
J Pain Res. 2019 Jan 14;12:345-352. doi: 10.2147/JPR.S180792. eCollection 2019.

Ethical justification of single-blind and double-blind placebo-controlled response tests in neuropathic pain and N-of-1 treatment paradigm in clinical settings.

Author information

Institute for Neuropathic Pain, Bosch en Duin, The Netherlands,
Institute for Neuropathic Pain, Amsterdam, The Netherlands.
Pain Management Centre, Charing Cross Hospital Imperial Healthcare NHS Trust, London, UK.


At our center in the Netherlands, patients, who very often are treatment resistant to the analgesics recommended in the guidelines, suffering from symmetrical peripheral neuropathic pain are treated exclusively. We have developed a number of compounded topical formulations containing classical co-analgesics such as ketamine, baclofen, amitriptyline, and phenytoin for the treatment of neuropathic pain in treatment-resistant patients. In order to identify putative responders and exclude an (initial) placebo-response, we developed single-blind and double-blind placebo-controlled response tests. The test can be performed when the patient has a symmetrical polyneuropathy with a pain score difference of not more than 1 point on the 11-point numerical rating scale (NRS) between bilateral pain areas. On one area (eg, left foot) the placebo cream and on the other area (eg, right foot) the active cream will be applied. Within a time frame of 30 minutes, patients are considered responders if they rate a pain difference of at least 2 points on the NRS between the bilateral areas on which the active cream and placebo cream are applied. Response tests can be easily conducted during the first consultation. In this paper, we explore the ethical context of using a placebo in clinical practice in a single-blind and double-blind fashion to improve and individualize treatment of neuropathic pain outside a context of a formal clinical trial.


enrichment; ethics; topical; treatment; trial

Conflict of interest statement

Disclosure JMKH and DJK are holders of two patents: 1) topical phenytoin for use in the treatment of peripheral neuropathic pain and 2) topical pharmaceutical composition containing phenytoin and a (co-)analgesic for the treatment of chronic pain. The authors report no other conflicts of interest in this work.

Supplemental Content

Full text links

Icon for Dove Medical Press Icon for PubMed Central
Loading ...
Support Center