Changes in milk composition associated with pethidine-PCEA usage after Caesarean section.

The effect of pethidine as patient-controlled epidural analgesia (PCEA) on specific biochemical components in breast milk in relation to the timing of secretory activation is not well investigated. The aim of this study was to compare biochemical timing of secretory activation between women who had a vaginal (V) or Caesarean birth with pethidine-PCEA (CBP). Several milk samples were collected daily from 36 mothers (17 V, 19 CBP) for the first 265 h post-partum. Protein and lactose concentrations and Na+ and K+ ion levels were measured. Samples were assigned to three time periods: 0-72, >72-165 and >165-265 h post-partum for statistical analyses. Data were analyzed using linear mixed effect models. In the first 72 h post-partum, the mean difference in lactose concentration was 5 gL-1 higher in group V (P < 0.05). From >72-165 h post-partum, protein and Na+ concentrations were lower in group V (P = 0.05, P = 0.02), and K+ levels were higher in group V (P < 0.001). From >165-265 h post-partum, there were no significant differences between the groups. Biochemically, secretory activation had occurred by 72 h post-partum in both groups. There were greater variations in measured biochemical components observed within group CBP initially. However, by 165 h post-partum, there were no differences in the biochemical components between the groups. This suggests that effects of pethidine-PCEA are diminished by 72 h post-partum and undetected by 165 h.

A phase I pharmacokinetic and bioavailability study of a sublingual fentanyl wafer in healthy volunteers.

BACKGROUND: The sublingual administration of opioids is a simple and noninvasive method that provides rapid analgesia. In this phase I study we investigated the pharmacokinetics and bioavailability of a fentanyl wafer in healthy volunteers. The principal study objective was to investigate the pharmacokinetic profile of a new sublingual fentanyl wafer and to establish its absolute bioavailability. METHODS: Twenty-four healthy volunteers, mean age 23 years, were randomly assigned to receive the equivalent of fentanyl 100 µg by both the sublingual and IV routes. Blood samples were collected in sterile polypropylene tubes for 24 hours after each fentanyl administration. The pharmacokinetic parameters were determined by model-independent pharmacokinetic analyses of the plasma fentanyl concentration-time profiles. RESULTS: The mean absolute bioavailability of the sublingual fentanyl wafer was 78.9% (90% confidence interval [CI] 51.1% to 121.7%). The first detectable plasma fentanyl concentration time ranged from 2 to 10 minutes in all volunteers, and the mean (±SD) time to peak plasma concentration at 0.91 (±0.73) hours after administration. CONCLUSION: Sublingual administration of fentanyl as a wafer product resulted in rapidly detectable plasma fentanyl concentrations. The absolute bioavailability of 78.9% indicated a high systemic availability of fentanyl and suggests that further development of this wafer is justified.

Neuroanesthesia for the pregnant woman.

Neuroanesthesia for the pregnant patient is required infrequently, and evidence-based recommendations for neuroanesthetic management are sparse. We present a framework for a practical approach to anesthesia of the pregnant patient with subarachnoid or intracerebral hemorrhage, intracranial tumor, traumatic brain injury, spinal tumor, or spinal injury. The importance of a team-approach is emphasized. The anesthesiologist may have to anesthetize the pregnant patient for neurosurgery well before delivery, for cesarean delivery at the time of the neurosurgical procedure, or for delivery after neurosurgery. These scenarios are discussed along with fetal safety and anesthetic considerations for interventional neuroradiology.

The clinical applications of intranasal opioids.

Opioids are widely used in all fields of pain management and may be delivered by a number of routes of administration. The intranasal administration of opioid is a convenient route of transmucosal drug delivery that has received limited attention. Potential advantages compared with parenteral or oral administration include avoidance of painful injection, avoidance of risks associated with intravenous access, rapid onset and titration to effect, good bioavailability, and high levels of acceptability and familiarity to patients. These features also lend themselves to the benefits of patient-controlled delivery systems and commercially available devices are described. In this paper we briefly consider the relevant pharmacology of intranasal drug delivery; opioid drugs and formulations; and delivery devices used clinically for intranasal administration. We review the clinical applications of intranasal opioid analgesia. These have included use for in-hospital pain management in adult and paediatric populations, in the emergency department, perioperatively and in burns units. Out-of-hospital use has included palliative care and paramedic use during retrieval and transfer to hospital. Many small trials suggest that intranasal opioids play a useful role in pain management, but large clinical trials are needed to better define advantages, safety and acceptability.