Acute pain management: unmet needs and new advances in pain management

Effect of ADRA2A gene polymorphisms on the anesthetic and analgesic effects of dexmedetomidine in Chinese Han women with cesarean section

It is well known that differences in drug reactions among individuals are widespread, and therefore the study of genetic polymorphisms of drug targets has become a research hotspot. Dexmedetomidine is clinically effective by acting on α2 adrenergic receptor and the impact of the adrenoceptor α2A gene (ADRA2A) polymorphisms on the anesthetic and analgesic effects of dexmedetomidine is related to the clinical application of dexmedetomidine. The present study aimed to analyze the effects of the rs1800035, rs201376588 and rs775887911 locus single-nucleotide polymorphisms of the ADRA2A on the anesthetic and analgesic effects of dexmedetomidine in Chinese Han women. A total of 434 Chinese women undergoing cesarean section were enrolled in this study. A 3-ml fasting venous blood sample was collected from all subjects for genomic DNA extraction and genotype detection. The pre-anesthetic and post-anesthetic pain threshold (PTh), pain tolerance threshold (PTTh), mean arterial pressure, heart rate, blood oxygen saturation, cortisol (Cor) content, blood glucose (Glu) content, opioid usage, patient-controlled analgesia pressing times, surgical satisfaction and postoperative adverse reactions were recorded. The visual analogue scale (VAS) and Ramsay sedation score were evaluated. PTh and PTTh in the wild-type women were higher than those in the women with mutations (P<0.05). The postoperative VAS scores of wild-type women were lower than those of mutants (P<0.05). The Ramsay sedation scores of wild-type patients at 12 h after the operation were significantly higher than in those with mutations (P<0.05). The levels of Cor and Glu in women with mutations were significantly higher than those of wild-type women at 12, 24 and 48 h after surgery (P<0.05). The satisfaction with surgery of wild-type patients was higher than that of patients with mutations (P<0.05). Gene mutations of rs1800035, rs201376588 and rs775887911 loci in the ADRA2A gene reduced the anesthetic and analgesic effect during and after cesarean section in Chinese Han women. Postoperative analgesia of mothers with mutations may require higher doses of analgesics.

Acute Pain Management

Acute pain management is improving steadily over the past few years, but training and professional education are still lacking in many professions. Untreated or undertreated acute pain could have detrimental effects on the patient in terms of comfort and recovery from trauma or surgery. Acute undertreated pain can decrease a patient's vascular perfusion, increase oxygen demand, suppress the immune system, and possibly risk increased incidence of venous thrombosis. Although acute postoperative pain needs to be managed aggressively, patients are most vulnerable during this period for developing adverse effects, and therefore, patient assessment and careful drug therapy evaluation are necessary processes in therapeutic planning. Acute pain management requires careful and thorough initial assessment and follow-up reassessment in addition to frequent dosage adjustments, and managing analgesic induced side effects. Analgesic selection and dosing must be based on the patient's past and recent analgesic exposure. There is no single acute pain management regimen that is suitable for all patients. Analgesics must be tailored to the individual patient.

The efficacy of preoperative versus postoperative rofecoxib for preventing acute postoperative dental pain: a prospective randomized crossover study using bilateral symmetrical oral surgery

BACKGROUND

Previous data have demonstrated that rofecoxib has good analgesic efficacy for acute postoperative dental pain. However, up to half of these patients require rescue analgesics within the first 24 hours. As the timing of analgesic interventions may be an important factor in pain control, the present study tested the hypothesis that rofecoxib administered preoperatively would improve the analgesic efficacy and reduce rescue analgesic requirements within the first 24 hours compared with postoperative administration.

METHODS

This was a double-blind, randomized, crossover study where 45 patients had each of their identical impacted mandibular third molars removed under local anesthesia on 2 separate occasions. Patients acted as their own control; one side was pretreated with rofecoxib 50 mg, 2 hours before surgery, followed by placebo 15 minutes after surgery, and the contralateral side was pretreated with placebo 2 hours before surgery and posttreated with rofecoxib 50 mg 15 minutes after surgery. The difference in postoperative pain between 2 sides was assessed by 4 primary end-points: pain intensity as measured by a 100-mm visual analogue scale hourly for 12 hours, time to rescue analgesic, postoperative analgesic consumption, and patient's global assessment.

RESULTS

Patients reported significantly lower pain scores (P = 0.04), longer time to rescue analgesic (P = 0.02), lesser postoperative analgesic consumption (P = 0.008), and better global assessment (P = 0.01) in the pretreated compared with the posttreated sides. There were significantly more patients in the pretreated group who did not required rescue analgesic within the first 24 hours (80% vs. 58%, P = 0.01), and the pain scores were extremely low in both groups during the 12 hours postoperative period (9.8 +/- 5.0 mm vs. 14.3 +/- 7.4 mm).

CONCLUSION

Rofecoxib is an excellent analgesic for preventing postoperative dental pain and when given 2 hours preoperatively rendered most patients relatively pain free, requiring no rescue analgesics on the first postoperative day.

Preoperative oral rofecoxib reduces postoperative pain and tramadol consumption in patients after abdominal hysterectomy

We designed this study to determine whether the administration of a preoperative dose of rofecoxib to patients undergoing abdominal hysterectomy would decrease patient-controlled analgesia (PCA) tramadol use or enhance analgesia. Sixty patients were randomized to receive either oral placebo or rofecoxib 50 mg 1 h before surgery. All patients received a standard anesthetic protocol. Intraoperative blood loss was determined. At the end of surgery, all patients received tramadol IV via a PCA-device. Pain scores, sedation scores, mean arterial blood pressure, heart rate, and peripheral oxygen saturation were assessed at 1, 2, 4, 6, 8, 12, and 24 h after surgery. Total and incremental tramadol consumption at the same times was recorded from the PCA-device. Antiemetic requirements and adverse effects were noted during the first postoperative 24 h. Duration of hospital stay was also recorded. The pain scores were significantly lower in the rofecoxib group compared with the placebo group at 6 times during the first 12 postoperative h (P < 0.05). The total consumption of tramadol (627 +/- 69 mg versus 535 +/- 45 mg; P < 0.05) and the incremental doses at 1, 2, 4, 6, 8, and 12 h after surgery were significantly more in the placebo group than in the rofecoxib group. There were no differences between groups in intraoperative blood loss, sedation scores, hemodynamic variables, peripheral oxygen saturation, antiemetic requirements, or adverse effects after surgery. The length of hospital stay was also similar in the groups. We conclude that the preoperative administration of oral rofecoxib provided a significant analgesic benefit and decreased the opioid requirements in patients undergoing abdominal hysterectomy.

IMPLICATIONS

This study was designed to determine whether the administration of a preoperative dose of rofecoxib to patients undergoing abdominal hysterectomy would decrease patient-controlled analgesia tramadol use or enhance analgesia. We conclude that the preoperative administration of oral rofecoxib provided a significant analgesic benefit and decreased the opioid requirements in patients undergoing abdominal hysterectomy.