Intravenous Administration of Vitamin C in the Treatment of Herpes Zoster-Associated Pain: Two Case Reports and Literature Review

Does the vitamin C level affect postoperative analgesia in patients who undergo orthognathic surgery?

Vitamin C has a critical role in pain management because of its antioxidative, neuroprotective, and anti-nociceptive properties. Oxidative stress caused by surgery increases the requirement for vitamin C. The aim of this study was to evaluate the change in vitamin C level and its effect on postoperative pain in patients undergoing orthognathic surgery. Thirty patients were included in the study. The relationships between the postoperative plasma vitamin C level, duration of surgery, postoperative analgesic consumption, and pain scores (visual analogue scale) were analysed. The difference between the mean pre- and postoperative vitamin C levels was found to be statistically significant (7.5 ± 2.9 mg/l vs 4.9 ± 2.3 mg/l, respectively; P = 0.001). There was no significant relationship between the duration of surgery and the vitamin C level decrease (P > 0.05). There was an inverse correlation between the postoperative vitamin C level and the amount of analgesic requested via patient-controlled analgesia (r = -0.699, P < 0.001). The findings suggest that, in patients who undergo orthognathic surgery, plasma vitamin C levels decrease significantly (34.6%), and an increase in the duration of surgery is not associated with any decrease in the vitamin C levels. A low postoperative plasma vitamin C level was found to be associated with greater postoperative analgesic consumption. In patients with preoperative plasma vitamin C levels ≤ 42 µmol/l, perioperative vitamin C administration may be considered for postoperative pain management.

Risk Factors for Poor Pain Control in Zoster-Associated Pain: A Retrospective Study

INTRODUCTION

The objective was to investigate the risk factors for poor pain control in patients with herpes zoster (HZ)-associated neuropathic pain treated with drugs combined with nerve block therapy. Neuropathic pain commonly follows HZ. Nerve block therapy is the most commonly used clinical treatment for such pain, combining anti-inflammation and analgesia to prevent peripheral sensitization of nerve.

METHODS

Using clinical practice data from a cohort study at our research center, we established a multivariate logistic regression model to investigate potential risk factors for poor control of zoster-associated pain (ZAP) treated with drugs plus nerve block therapy, including demographic characteristics, complications, laboratory tests, and characteristics of HZ attacks.

RESULTS

Of the 429 patients with ZAP who received drugs plus nerve block therapy, 95 (22.14%) had poor pain control after treatment. The risk of poor pain control was closely related to presence of cancer (odds ratio (OR) 4.173, 95% confidence interval (CI) 1.342-12.970), numerical rating scale score on admission (OR 1.929, 95% CI 1.528-2.434), and red blood cell count (OR 0.560, 95% CI 0.328-0.954). Area under the receiver operator characteristic curve was 0.730. Goodness of fit (Hosmer-Lemeshow) was 0.874.

CONCLUSIONS

The risk of poor pain control in patients with ZAP increased as a result of certain patient characteristics and complications, especially severe pain before treatment and cancer.