Intravenous Nefopam Reduces Postherpetic Neuralgia during the Titration of Oral Medications.
BACKGROUND
The recently known analgesic action mechanisms of nefopam (NFP) are similar to those of anticonvulsants and antidepressants in neuropathic pain treatment. It is difficult to prescribe high doses of oral neuropathic drugs without titration due to adverse effects. Unfortunately, there are few available intravenous analgesics for the immediate management of acute flare-ups of the chronic neuropathic pain. The aim of this study was to determine the additional analgesic effects for neuropathic pain of NFP and its adverse effects during the titration of oral medications for neuropathic pain among inpatients with postherpetic neuralgia (PHN).


METHODS
Eighty inpatients with PHN were randomly divided into either the NFP or normal saline (NS) groups. Each patient received a 3-day intravenous continuous infusion of either NFP with a consecutive dose reduction of 60, 40, and 20 mg/d, or NS simultaneously while dose titrations of oral medications for neuropathic pain gradually increased every 3 days. The efficacy of additional NFP was evaluated by using the neuropathic pain symptom inventory (NPSI) score for 12 days. Adverse effects were also recorded.


RESULTS
The median NPSI score was significantly lower in the NFP group from days 1 to 6 of hospitalization. The representative alleviating symptoms of pain after using NFP were both spontaneous and evoked neuropathic pain. Reported common adverse effects were nausea, dizziness, and somnolence, in order of frequency.


CONCLUSIONS
An intravenous continuous infusion of NFP reduces spontaneous and evoked neuropathic pain with tolerable adverse effects during the titration of oral medications in inpatients with PHN.
Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Yangsan, Korea.
Young Chan
YC
Joo
Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Yangsan, Korea.
Eun Sung
ES
Ko
Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Yangsan, Korea.
Jae Geun
JG
Cho
Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Yangsan, Korea.
Young Min
YM
Ok
Department of Plastic Surgery, School of Medicine, Dongguk University, Gyeongju, Korea.
Gyu Yong
GY
Jung
Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Yangsan, Korea.
Kyung Hoon
KH
Kim
anticonvulsants; antidepressants; nefopam; postherpetic neuralgia; titration