Additive analgesic effect of codeine and paracetamol can be detected in strong, but not moderate, pain after Caesarean section. Baseline pain-intensity is a determinant of assay-sensitivity in a postoperative analgesic trial. [The efficacy of paracetamol (Tylenol) and acetyl salicylic acid (Aspirin) in treating postoperative pain]. Analgesic efficacy and safety of intravenous paracetamol (acetaminophen) administered as a 2 g starting dose following third molar surgery. [Analgesic and opioid-sparing effects of intravenous paracetamol in the early period after aortocoronary bypass surgery]. Clinical equivalence of IV paracetamol compared to IV dipyrone for postoperative analgesia after surgery for breast cancer. Intravenous paracetamol improves the quality of postoperative analgesia but does not decrease narcotic requirements. Analgesic effect of i.v. paracetamol: possible ceiling effect of paracetamol in postoperative pain. Assessing analgesia in single and repeated administrations of propacetamol for postoperative pain: comparison with morphine after dental surgery. [Effect of nonsteroidal anti-inflammatory drugs and paracetamol on hemodynamic changes during postoperative analgesia in children].
A randomized, double-blind, placebo-controlled single oral dose study was done in order to examine whether codeine has an additive analgesic effect to that of paracetamol for moderate and strong postoperative pain after abdominal surgery. The maximum recommended single dose of paracetamol 1000 mg (Paracet) was compared with a combination of a submaximal dose of paracetamol 800 mg plus codeine 60 mg (Paralgin forte) and placebo for pain relief after Caesarean section in 125 patients.
                Visual analogue pain intensity score (VAS 0-100 mm) and categorical pain relief score were recorded for 6 hours after the study drug intake. The main efficacy variables analyzed were: pain intensity difference and summed pain intensity differences during the first 3 and 6 h after study drug intake, total pain relief during the first 3 and 6 h, global evaluation score at the end of the observation period, and time to rescue analgesic.
                Because of protocol violations, 17 patients were excluded from the analysis of effects. Among the 108 patients included in the analysis of analgesic effect, 49 patients had moderate baseline pain (VAS between 40 and 60 mm on a 100 mm scale), and 59 patients had strong baseline pain (VAS more than 60 mm). In patients with strong baseline pain, statistically highly significant differences were documented in efficacy variables between the active drugs and placebo and between the two active drugs. However, in patients with moderate baseline pain, no differences were found between the study drugs in any of the analgesic efficacy variables.
                This study thus confirms that codeine has additive analgesic effect to paracetamol in pain after surgery. Our results show the importance of initial pain intensity in postoperative assessment of analgesic drugs. Assay-sensitivity and test power are increased by selecting patients with sufficiently high initial pain intensity and by comparing groups of patients with identical surgery and similar demographic variables. In a randomized, double-center, double-blind, parallel group study the analgesic effect of a single dose of paracetamol (1000 mg) and acetyl salicylic acid (1000 mg) was compared with placebo in patients with moderate to severe postoperative pain following the surgical removal of a wisdom tooth. The most important finding was the statistically significantly shorter period until the onset of the action of paracetamol as against acetyl salicylic acid. The recommended dose for intravenous (IV) paracetamol injection in adults is 1g, however pharmacokinetic and pharmacodynamic findings suggest that a better analgesia could be obtained with a 2 g starting dose.
                A single-centre, randomised, double-blind, placebo-controlled, 3-parallel group study was performed to demonstrate the analgesic efficacy and safety of IV paracetamol 2 g. Following third molar surgery, patients reporting moderate to severe pain received a single 15-min infusion of either IV paracetamol 2 g, IV paracetamol 1g or placebo. Efficacy and safety were evaluated over 8 h. Laboratory tests were performed before and 48 h after drug administration.
                Two hundred and ninety seven patients (132 = IV paracetamol 2g; 132 = IV paracetamol 1g; 33 = placebo) were randomised and completed the study. The summed pain relief over 6h (TOTPAR6) was significantly superior with IV paracetamol 2 g as compared to IV paracetamol 1g and placebo (p < 0.0001). Pain relief scores of IV paracetamol 2g were significantly superior to IV paracetamol 1g and to placebo from T30' to T8h (p < 0.0001). Median duration of analgesia was significantly longer following IV paracetamol 2 g compared to IV paracetamol 1g and placebo (p < 0.0001). Adverse events occurred with the same frequency in the 3 treatment groups. No clinically significant changes from baseline were observed for vital signs or laboratory tests.
                The analgesic efficacy of a 2 g starting dose of IV paracetamol was superior over the recommended dose of 1g in terms of magnitude and duration of analgesic effect for postoperative pain following third molar surgery, with no significant difference between groups regarding safety. The study was to evaluate the analgesic and opioid-sparing effect of intravenous paracetamol injections in cardiosurgical patients in the early postoperative period. Adequate analgesia within the first 12-18 hours of the early postoperative period is very important for a good prognosis of the further course of pain syndrome and for the reduction of a risk for its progression to its chronic form. In early studies, propacetamol lowered morphine use after orthopedic and gynecological operations. The efficacy of paracetamol used in cardiac surgery has been little studied and the results of the studies are conflicting. The randomized, blind, placebo-controlled study included patients after aortocoronary bypass surgery, of them 22 patients received paracetamol and 23 had placebo. The test drug (perfalgan 100 ml or placebo) was intravenously injected 30 min before extubation and then every 6 hours within succeeding 18 hours. The intensity of the pain syndrome was rated by a 5-score verbal scale every 2 hours. With pain score of 2 or more, promedol was intramuscularly administered in a dose of 10 mg. Inspiratory volume was recorded before extubation and the first administration of a drug just after extubation and then every 2 hours. The baseline indices did not differ in both groups. Throughout the observation, the inspiratory volume was lower in the paracetamol group than in the placebo group; however, there was a statistically significant difference (p = 0.012) in the reduction in the manifestations of the pain syndrome (by 81%) only just after tracheal extubation. During this period, inspiratory volume values were higher in the paracetamol group; however, a statistically significant (39%) difference between the groups in the mean values was obtained only during and 2 hours after extubation. In the perfalgan group, the mean total use of promedol was 36% less than in the placebo-group, which was statistically significant (p = 0.019). The early postoperative use of paracetamol after myocardial revascularization reduces the intake of opioids and diminishes the intensity of the pain syndrome within the first hours after extubation, which promotes a higher thoracic excursion, as confirmed by a statistically significant increase in the maximum inspiratory capacity. To assess clinical efficacy of IV paracetamol 1 g and IV dipyrone 1 g on a 24-h dosing schedule in this randomised, double-blinded study of 40 ASA I-III (American Society of Anesthesiologists classification of physical status) patients undergoing surgery for breast cancer.
                General anaesthesia using remifentanil and propofol was performed for surgery. The patients were randomly allocated to two groups, receiving infusions of paracetamol 1 g/100 mL (Para Group) or of dipyrone 1 g/100 mL (Dipy Group) 30 min before arrival in the recovery area and every 6 h up to 24 h postoperatively. All patients had unrestricted access to opioid rescue medication via an IV patient-controlled analgesia (PCA) device.
                The primary variables for clinical equivalence were the differences between the mean values for pain scores at rest and pain scores on coughing over 30 h postoperatively. The equivalence margin was determined as +/-10 mm on the visual analogue scale (VAS).
                Regarding pain scores at rest, the 90% CI of the mean differences between the treatment groups over 30 h postoperatively was found to be within the predefined equivalence margin [+7.5/-6.2], and the CI values for pain scores on coughing [+7.3/-9.0] were similar. The two groups did not differ in cumulative opioid rescue consumption (Dipy-Group 14.8 +/- 17.7 mg vs. Para Group 12.1 +/- 8.8 mg, p = 0.54) nor in piritramide loading dose (Dipy Group 0.95 +/- 2.8 mg vs. Para Group 1.3 +/- 2.8 mg, p = 0.545). Five patients in the Dipy Group experienced hypotension in contrast to none in the Para Group (p = 0.047). There were no significant between-treatment differences for other adverse events, patient satisfaction scores (p = 0.4) or quality of recovery scores (p = 0.3).
                IV paracetamol 1 g is clinically equivalent to IV dipyrone 1 g for postoperative analgesia after surgery for breast cancer. Paracetamol, a centrally acting inhibitor of cyclooxygenase, has less gastrointestinal and platelet-inhibiting side effects and is clinically better tolerated than nonsteroidal anti-inflammatory drugs. Therefore, it will be ideally suited for postoperative pain relief. In this prospective, double-blind, randomized, placebo-controlled study, we evaluated the analgesic efficacy, opioid-sparing effect and effects on opioid-related adverse effects of intravenous (IV) paracetamol in combination with IV morphine after lumbar laminectomy and discectomy. Forty patients were divided into 2 groups (n=20 each) to receive either paracetamol 1 g (group 1) or 0.9% NaCl 100 ml (group 2) at the end of the operation and at 6-hour intervals over 24 hours. IV patient-controlled analgesia with morphine was used as a rescue analgesic in both groups. Pain was evaluated at rest and on movement at the 1st, 2nd, 4th, 6th, 12th, 18th, and 24th hours using a visual analog scale. Hemodynamic parameters, morphine usage, patient satisfaction, and probable side effects were also evaluated. Pain scores at rest and on movement at the 12th, 18th, and 24th hours were significantly lower in group 1 (P<0.001). Morphine consumption was not statistically significantly different between the groups (P>0.05). Vomiting in group 2 was significantly higher (P=0.027). Significantly more patients in the paracetamol group rated their pain management as excellent (45% vs. 5%). Although repeated IV paracetamol usage after lumbar laminectomy and discectomy did not demonstrate a significant opioid-sparing effect, it did decrease visual analog scale scores at certain evaluation times and incidence of vomiting and increase patient satisfaction. Despite the widespread use of paracetamol for many years, the analgesic serum concentrations of paracetamol are unknown. Therefore the correlation between serum paracetamol concentrations and the analgesic effect was studied.
                Sixty-four women undergoing laparoscopic sterilization were included in a double-blind, placebo-controlled, randomized study. Patients were given i.v. propacetamol 40 mg kg(-1) (group H), 20 mg kg(-1) (group I), 10 mg kg(-1) (group L) or placebo after surgery. Alfentanil was available via patient-controlled analgesia (PCA) during the 4-h postoperative study period. The patients' self-reported pain was registered on the visual analog scale (VAS). A pharmacokinetic model was fitted to the paracetamol data.
                One to 3 h after injection of propacetamol the alfentanil consumption was significantly (P = 0.01-0.04) higher in the placebo group compared with groups H, I, and L receiving propacetamol. There were no significant differences between the amounts of alfentanil consumed in groups H, I, and L. Initial VAS-scores were moderate (5.4-6.2), and declined significantly (P < 0.0001) over time, with no difference between groups. Paracetamol followed an open two-compartment model with i.v. administration and first order elimination. The estimated concentrations immediately (t = 0) after injection were 56 mg l(-1) (H), 28 mg l(-1) (I) and 14 mg l(-1) (L).
                We showed a significant opioid-sparing effect of paracetamol in the immediate postoperative period. Pharmacokinetic data were in accordance with other studies. Our results suggest that a ceiling effect of paracetamol may be present at i.v. doses of 5 mg kg(-1), i.e. a serum concentration of 14 mg l(-1), which is a lower dose than previously suggested.
                Copyright Acta Anaesthesiologica Scandinavica 47 (2003) We conducted this double-blinded, randomized study to assess the analgesic effect of repeated administrations of paracetamol, administered as propacetamol, an injectable prodrug formulation of paracetamol, and to compare this with the analgesic effects of morphine. Patients experiencing moderate to severe pain after elective surgical removal of bone-impacted third-molar teeth under general anesthesia were randomly assigned to receive IV propacetamol 2 g (n = 31), IM morphine 10 mg (n = 30), or placebo (n = 34). Five hours later, the treatments were readministered at half of the previous dosages. Standard measures of analgesia were collected repeatedly for 10 h. Propacetamol and morphine were significantly more effective than placebo in all primary measures of analgesia over 5 h after the first administration and globally over 10 h (first and second administrations). After the first dose, 21 of the 34 patients in the placebo group required rescue medication, compared with 6 of the 31 in the propacetamol group (P < 0.0009) and 4 of the 30 in the morphine group (P < 0.0001). No statistically or clinically significant differences were found between propacetamol and morphine for any sum or peak measures of analgesia. No serious adverse events were reported; adverse events were significantly less frequent in the propacetamol group than in the morphine group (P < 0.027). Propacetamol administered IV in repeated doses (2 g followed by 1 g) has a significant analgesic effect that is indistinguishable from that of morphine administered IM (10 mg followed by 5 mg) after dental surgery, with better tolerability.
                After moderately painful surgical procedures, IV paracetamol, administered as propacetamol, may be an asset in the control of acute postoperative pain. The purpose of the present study was to comparatively assess the adequacy of postoperative analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs) and paracetamol in children undergone "minor" surgical interventions. For postoperative analgesia in children, the authors used paracetamol in a single dose of 25-30 mg/kg, diclofenac in a dose of 1.5-2.0 mg/kg, which were rectally administered as suppositories, as well as diclofenac in the same dose as intramuscular injections (Group 1). A comparison was made with postoperative analgesia using analgin and promedole (Group 2 (control)). Group 1 comprised 63 patients and Group 2 included 26 patients with identical diseases (inguinal hernias, varicocele, phimosis). Functional parameters were recorded in patients in the lying position before, 30 min, 1, 2, and 3 hours after surgery. The efficiency of postoperative analgesia was evaluated, by using central hemodynamic parameters that many investigators consider to be one of the major criteria for the adequacy of anesthesia. Comparison of postoperative data has revealed a difference between the groups, which suggests that the use of NSAIDs and paracetamol for preventive and postoperative analgesia in children substantially improves the postoperative period and promotes a rapid rehabilitation in patients. Comparative analysis of the efficiency of postoperative analgesia of the above agents has indicated that diclofenac and paracetamol have a sufficient analgesic activity and at the same time do not show the adverse reactions unique to narcotic analgesics.
A single dose of paracetamol provides effective analgesia for about half of patients with acute postoperative pain, for a period of about four hours, and is associated with few, mainly mild, adverse events.