Wrist Acupoint Injection of Granisetron Outperforms IV Route Against Postoperative Nausea in Trial

Injecting the anti-nausea drug granisetron into a traditional acupuncture point on the wrist cut the rate of moderate-to-severe postoperative nausea by more than half compared with giving the same dose intravenously, according to a randomized controlled trial conducted at West China Second University Hospital of Sichuan University in Chengdu. The study, published in Frontiers in Pharmacology, enrolled 244 women undergoing elective gynecologic laparoscopic surgery under general anesthesia and found that only 14.8 percent of patients who received the drug at the PC6 acupoint experienced moderate-to-severe nausea within 24 hours of surgery, versus 32.8 percent of those who received it through a standard intravenous line. Postoperative nausea and vomiting remains one of the most common and stubborn complications of surgery, affecting roughly 20 to 30 percent of general surgical patients and climbing as high as 80 percent in high-risk groups such as women, nonsmokers, and people with a history of motion sickness or previous postoperative nausea and vomiting.

Beyond the obvious discomfort, the condition can lead to dehydration, electrolyte imbalances, and even wound separation, prolonging recovery and degrading quality of life in the crucial hours after an operation. Although modern anesthetic techniques and a growing arsenal of antiemetic drugs have improved matters, moderate-to-severe nausea in particular remains inadequately controlled, and concerns about drug side effects have fueled interest in complementary approaches. The PC6 acupoint, known in traditional Chinese medicine as Neiguan, sits on the volar side of the forearm about three finger-widths above the wrist crease, between the tendons of the palmaris longus and flexor carpi radialis muscles.

Both traditional practice and modern clinical research have linked stimulation of this point to relief of nausea, and the Fourth Consensus Guidelines for the Management of Postoperative Nausea and Vomiting recognize PC6 stimulation as a complementary and alternative therapy. Conventional stimulation methods such as acupuncture needles, manual massage, or transcutaneous electrical nerve stimulation can be time-consuming and labor-intensive, however, which has driven interest in acupoint injection, a technique in which a medicinal solution is delivered directly into the acupoint, theoretically combining the effects of the meridian, the point itself, and the pharmacological agent. The trial was designed as a prospective, single-center, randomized controlled study with an exploratory superiority framework.

Between July and December 2024, the researchers screened 264 patients and randomized 244 women aged 18 to 50 with American Society of Anesthesiologists physical status I or II into four equal groups of 61. All patients received 5 mg of intravenous dexamethasone during anesthesia induction as a fixed antiemetic backbone, consistent with guideline recommendations. At the end of surgery, before patients emerged from anesthesia, the PC6 granisetron group received 2 mg of granisetron injected into the PC6 acupoint on the non-dominant forearm; the intravenous granisetron group received the same 2 mg dose through the existing IV line over 30 seconds; the PC6 saline group received 2 mL of normal saline injected at the acupoint using an identical technique as a sham control; and the control group received no additional prophylaxis.

Four control patients who inadvertently received a protocol-violating 10 mg dexamethasone dose were excluded, leaving 57 analyzable patients in that arm. The injection procedure was standardized in detail. After disinfecting a 5-centimeter circle of skin with iodophor, a trained anesthesiologist inserted a 25-gauge needle perpendicularly to a depth of approximately 2 centimeters, aspirated gently to confirm no blood return, and injected the solution slowly over 10 to 15 seconds.

The site was compressed with a sterile cotton swab for at least one minute and no massage was applied. Because all interventions took place while patients were still fully anesthetized, participants could not perceive the injection site or route, preserving blinding. Outcome assessors were also blinded to group assignment, and the randomization sequence was concealed in sequentially numbered, opaque envelopes.

Follow-up evaluations for nausea and vomiting were conducted at 2, 6, 12, and 24 hours after surgery using a 0 to 10 visual analog scale, with a score of 4 or higher defining moderate-to-severe nausea. The primary comparison favored the acupoint route decisively. Beyond the headline 24-hour figures, the separation between the PC6 granisetron group and the intravenous group emerged from 2 hours after surgery onward: at the 0-to-6-hour window, moderate-to-severe nausea occurred in 4.9 percent of the acupoint group versus 16.4 percent of the intravenous group, and at 0 to 12 hours the figures were 9.8 percent versus 26.2 percent.

The acupoint group also fared significantly better than the sham PC6 saline group and the control group, in which 43.9 percent of patients experienced moderate-to-severe nausea within 24 hours. Notably, the intravenous granisetron group differed from the control group only within the first 2 hours, whereas the benefit of acupoint injection persisted across the entire 24-hour observation period, suggesting a more sustained anti-nausea effect. The secondary outcomes told a more nuanced story.

Overall nausea incidence and vomiting frequency both fell in the active treatment groups compared with control, but the difference between the two granisetron routes was not statistically significant for vomiting, rescue medication use, time to hospital discharge, or 24-hour morphine-equivalent analgesic consumption. Three patients in each of the three intervention groups required rescue antiemetics, compared with six in the control group, a difference that did not reach significance. In a subgroup analysis restricted to the 179 patients, about three-quarters of the cohort, with an Apfel risk score of 3 or 4, indicating the highest baseline risk of postoperative nausea and vomiting, the acupoint group again showed significantly lower rates of moderate-to-severe nausea than all three other groups, with a P value below 0.01.

The sham saline arm proved important for interpretation. Moderate-to-severe nausea occurred in 29.5 percent of the PC6 saline group, numerically nearly double the 14.8 percent rate in the PC6 granisetron group, but the confidence interval for this comparison, a relative risk of 0.50 spanning 0.24 to 1.02, crossed the null value and the exact P value was 0.058. The authors are explicit that the trial was powered only for the primary comparison against intravenous granisetron and was underpowered for the saline comparison, so they do not claim a statistically significant incremental benefit of the drug over saline at the acupoint.

Instead, they describe a possible drug-acupoint synergistic trend that larger confirmatory trials should test. On safety, no complications such as swelling, pain, infection, or skin damage at the injection site were observed in any participant within 24 hours. The findings arrive against a backdrop of persistently high nausea rates even under standard dual prophylaxis.

The 32.8 percent incidence of moderate-to-severe nausea in the intravenous granisetron plus dexamethasone group is consistent with two large cohort studies of Chinese patients that reported postoperative nausea and vomiting rates of 31.7 to 48.7 percent despite combined 5-HT3 receptor antagonist and dexamethasone regimens. Gynecological laparoscopic surgery is inherently associated with high risk, which helps explain the elevated figures, and baseline characteristics including age, body mass index, fasting time, anesthesia and surgery durations, blood loss, fluid intake, and analgesic consumption were well balanced across the four groups, strengthening the internal validity of the comparison. The authors caution that several limitations temper the conclusions.

The study was conducted at a single center and included only female patients undergoing gynecological laparoscopic surgery, so generalizability to other populations and surgical contexts remains untested, and the results may not apply to patients with inherently low baseline risk. The biological mechanism by which acupoint injection might outperform systemic delivery, interpretable through traditional Chinese medicine theory as a potentiation of drug efficacy at a transport point, has yet to be elucidated from a modern biomedical perspective. The team calls for multicenter randomized controlled trials with larger and more diverse cohorts before PC6 acupoint injection of granisetron can be advocated for routine clinical use, whether in gynecological laparoscopic surgery or beyond.

For now, the trial stands as an intriguing signal that where, and not just whether, an antiemetic is delivered may shape how well it protects patients from one of surgery's most unwelcome aftereffects.

Subject of Research: PC6 acupoint injection versus intravenous granisetron for preventing postoperative nausea after gynecological laparoscopic surgery

Article Title: PC6 injection enhanced the preventive effect against postoperative nausea of granisetron compared with intravenous injection in gynecological laparoscopic patients: a randomized controlled study

Article References: Song, J., Tang, J., Gu, J., Tian, W., & Zhou, J. (2026). PC6 injection enhanced the preventive effect against postoperative nausea of granisetron compared with intravenous injection in gynecological laparoscopic patients: a randomized controlled study. Frontiers in Pharmacology, 17, Article 1840347. https://doi.org/10.3389/fphar.2026.1840347

Image Credits: AI Generated

DOI: 10.3389/fphar.2026.1840347

Keywords: postoperative nausea and vomiting, granisetron, PC6 acupoint, acupoint injection, randomized controlled trial, gynecological laparoscopic surgery, anesthesiology, antiemetics, Neiguan, dexamethasone, complementary medicine, clinical trial