Oral vs intravenous paracetamol for lower third molar extractions under general anaesthesia: is oral administration inferior?

BACKGROUND

Paracetamol formulations provide effective analgesia after surgery [Duggan ST, Scott LJ. Intravenous paracetamol (acetominophen). Drugs 2009; 69: 101-13; Toms L, McQuay HJ, Derry S, Moore RA. Single dose oral paracetamol (acetaminophen) for postoperative pain in adults. Cochrane Database Syst Rev 2008: CD004602]. I.V. paracetamol is superior to oral for pain rescue (Jarde O, Boccard E. Parenteral versus oral route increases paracetamol efficacy. Clin Drug Invest 1997; 14: 474-81). By randomized, double-blinded trial, we aimed to determine whether preoperative oral paracetamol provides inferior postoperative analgesia to preoperative i.v. paracetamol.

METHODS

One hundred and thirty participants received either oral paracetamol and i.v. placebo (Group OP), or oral placebo and i.v. paracetamol (Perfalgan™) (Group IP). Oral preparations were given at least 45 min before surgery; i.v. preparations after induction of anaesthesia. Pain was assessed by a 100 mm visual analogue scale (VAS) 1 h from the end of surgery. Rescue analgesia was given on request.

RESULTS

A total of 128 patients completed the study. There were no significant differences in baseline characteristics or intraoperative variables between the groups. The study was designed to reveal whether OP is inferior to IP, with an inferiority margin of 20%. The number of patients reporting satisfactory analgesia at 1 h with VAS ≤ 30 mm were 15 (OP) and 17 (IP), respectively. The secondary outcome measure of the mean (standard deviation) VAS (mm) for the whole of each group was 52 (22) for OP and 47 (22) for IP. Analysis of confidence intervals indicates that oral paracetamol is not inferior to i.v. paracetamol. The median survival (90% CI) to rescue analgesia request was 54.3 (51.2-57.4) min in Group OP and 57.3 (55.4-59.2) min in Group IP; there was no significant difference in this measure.

CONCLUSIONS

In this study of lower third molar extraction, oral paracetamol is not inferior to i.v. for postoperative analgesia. ISRCTN Registration http://www.controlled-trials.com/ISRCTN77607163.

Assessment of the bone status of Nigerian women by ultrasound and biochemical markers

Ultrasound analysis of the calcaneus and serum markers of bone turnover were used to examine the bone status of healthy Nigerian women who reside in an area of the world where dietary calcium intake is generally low and estrogen replacement therapy is not widely available. A total of 218 women (108 premenopausal and 110 postmenopausal) between the ages of 16 and 95 years were enrolled in the study. Broadband ultrasound attenuation (BUA) and speed of sound velocity (SOS) were measured and used to calculate the stiffness index (SI) of the calcaneus. In this cross-sectional study, the Nigerian women exhibited a marked age-dependent decline in SI that was defined by the regression equation SI = 105.9 - 6.62E-3 x Age2. SI was significantly correlated with age (r = -0.41, P < 0.001) and with serum NTx concentrations (r = -0.26, P < 0.001), but not with serum levels of bone-specific alkaline phosphatase (BSAP). Years since menopause was also significantly correlated with SI (r = 0.40, P < 0.001). A significant increase in serum NTx concentration occurred at least a decade before a significant decline in SI was evident. In the total study group, 24% of the women had T-scores indicative of osteopenia and 9% had T-scores indicative of osteoporosis, based on US reference data. Although the reported current incidence of fracture is low in women in sub-Saharan West Africa, these data show that after menopause Nigerian women have a decline in bone quality and increase in bone turnover similar to North American Caucasian women.