BackgroundPregabalin is recommended as an adjuvant analgesic for neuropathic cancer-related pain, and may be taken at all steps of the World Health Organization analgesic ladder. However, unlike opioids, pregabalin treatments are limited to an oral administration route. If patients have oral feeding difficulties, it is not possible to administer any drug as an adjuvant analgesic for neuropathic cancer-related pain. Therefore, the aim of the present study was to clarify the problems of pain control after pregabalin discontinuation in terminally ill cancer patients.MethodsOur subjects comprised cancer patients who died during their hospital stay and were referred between April 2013 and October 2015 to the palliative care team of the 899-bed Cancer Hospital at the Nippon Medical School Hospital in Japan. The medical records of each patient were retrospectively reviewed, and patient characteristics were recorded.ResultsWe obtained data on 183 patients during the study period. Thirty-eight (20.8 %) patients were treated with pregabalin. Thirty-three (86.8 %) out of 38 patients were prescribed pregabalin for neuropathic cancer-related pain. The incidence of bony metastases was significantly higher in patients administered pregabalin than in those not taking the drug (non-pregabalin group 32.4 % vs pregabalin group 57.9 %). Pregabalin was ultimately discontinued in all patients, with the main reason being oral feeding difficulties (81.6 %). After the discontinuation of pregabalin, the amount of opioid drugs administered was increased in 56.5 % of patients with oral feeding difficulties.ConclusionOur results demonstrated that the amount of opioid drugs administered was increased in more than 50 % of patients following the discontinuation of pregabalin, and was repeatedly increased for some patients. A new administration route is required for cancer patients unable to take oral medication.Trial registration UMIN000022507. May 28, 2016 retrospectively registered.

Objectives As commercially available pregabalin preparations are limited to oral administration, it is impossible to use it as an adjuvant analgesic for neuropathic cancer‐related pain in terminally ill cancer patients with oral feeding difficulties. The objective of this study was to develop a pregabalin suppository to be available at hospitals. Methods Pregabalin suppositories were prepared using bases comprising six different compositions of Witepsol H‐15, Witepsol S‐55, and Witepsol E‐75. The suppository release test and stability test were performed in vitro. The pharmacokinetics and pharmacodynamics of the suppositories were assessed in rats. Key findings In the in vitro releasing test, the pregabalin suppositories with H‐15, H‐15 : S‐55 = 1 : 1, H‐15 : S‐55 = 2 : 1, H‐15 : S‐55 = 1 : 2 released approximately 100% of the pregabalin within 180 min. Among these pregabalin suppositories, only the suppository with H‐15 : S‐55 = 2 : 1 demonstrated an equivalent AUC0−∞ with the oral administration group. Consistent with the results of the pharmacokinetic study, the pregabalin suppository with H‐15 : S‐55 = 2 : 1 exhibited antinociceptive effects. In addition, the pregabalin suppository with H‐15 : S‐55 = 2 : 1 was stable for 12 weeks when refrigerated with light shielding. Conclusions The pregabalin suppositories prepared in this study may be applicable for pain control for terminally cancer ill patients with oral feeding difficulties.

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