Effects of dexmedetomidine nasal spray combined with thoracic paravertebral block on sleep and pain in herpes zoster neuralgia: a randomized controlled trial

Herpes zoster neuralgia(HZN) is a common challenging problem, and there is a growing need to develop safe and effective treatments. Sleep disorders is commonly associated with HZN because pain intensity of HZN conditions is often worse at night. Evidence indicates that dexmedetomidine nasal spray is effective in alleviating pain and improving sleep quality in perioperative patients; however, no randomized controlled trials have evaluated its use in HZN. In this randomized, controlled, single-blind trial, a total of 103 patients were screened, and 70 patients were equally randomized to the dexmedetomidine(DEX) group and the control group. The DEX group received dexmedetomidine nasal spray at 1.0 ~ 1.5 µg·kg− 1 for three consecutive nights and the control group did not receive any nasal spray drugs. Both groups received a similar regimen of oral medication and a once-daily ultrasound-guided thoracic paravertebral block. Sleep parameters were monitored using smart wearable devices. The primary outcome was total sleep time during treatment. The group-by-time interaction for total sleep time was not statistically significant (F (2,140) = 2.36, P = 0.099). However, a significant main effect of group was observed (F (1,70) = 9.03, P = 0.004), indicating that participants in the DEX group had a significantly longer average total sleep time compared with the control group.The improvement in deep sleep time in the DEX group increased with treatment duration (least squares mean difference after 1 days = − 8.86 min [95% CI, − 23.53 to 5.82]; P = 0.236); after 2 days = 15.34 min [95% CI 0.67 to 30.02] ; P = 0.041; after 3 days = 20.26 min [95% CI 5.58 to 34.93]; P = 0.007). The number of nighttime awakenings was significantly lower in the DEX group at all time points (P < 0.001). Both the pain visual analogue scale score (F (1,70) = 10.90, P = 0.002) and the insomnia severity index score (mean difference = 1.86 [95% CI 0.44 to 3.28]; P = 0.011) were significantly lower in the DEX group compared with the control group. There were no statistical differences in the incidence of adverse events, including dizziness, nausea, drowsiness, hypotension, or the need for rescue medication. Dexmedetomidine nasal spray effectively and safely improved sleep quality and alleviated pain in patients with truncal herpes zoster neuralgia. These findings need to be validated in multicenter studies in diverse populations to ensure generalizability.