STUDIES OF DRUGS GIVEN BEFORE ANAESTHESIA XIX: THE OPIATES

Using Ridit analysis, a comparison was made of the overall effectsof what are generally considered to be equianalgesic doses ofsixteen opiates, with respect to their desired and toxic effectswhen given as premedication to a standard population. Four mixturesof opiates, the non-opiate diazepam and saline were also includedin the analysis. Results with all individual drugs have beenpreviously reported in detail. Under the conditions of thisstudy, pethidine 100 mg, papaveretum 20 mg and even morphine10 mg are too toxic to warrant their present popularity. Moreattention should be paid to the use of levorphanol 2 mg, diamorphine5 mg, methadone 10 mg and oxycodone 10 mg for premedication.These findings may be modified by the concomitant use of atropineor hyoscine. Papaveretum-hyoscine fully justifies its popularity,but its greater efficacy can be explained by its high morphinecontent and the action of hyoscine. Under appropriate conditionsdiazepam may be superior to any of the opiates for use in premedication.     

Antagonism of mivacurium block with edrophonium from various degrees of spontaneous recovery

Seventy adult patients received mivacurium 0.15 mg kg^–1during anaesthesia with thiopentone, nitrous oxide and 0.5%halothane. Neuromuscular block was monitored using mechanomyographyand train-of-four stimulation. Edrophonium 0.75 mg kg^–1was administered 5 or 10 min after mivacurium, or when the firstresponse in the TOF (T1) had recovered to 5, 10, 25 or 50% ofcontrol in groups of 10 patients each. A control group was allowedto recover spontaneously. The mean time taken from administrationof mivacurium to attaining a TOF ratio of 0.7 was between 19.3and 24.9 min in the groups given edrophonium, regardless ofthe time of administration, compared with 26.7 min in the spontaneousrecovery group. The differences, however, were not significantamong the groups showing little advantage in antagonizing mivacuriumblock.     

STUDIES OF DRUGS GIVEN BEFORE ANAESTHESIA XVII: THE NATURAL AND SEMI-SYNTHETIC OPIATES

The sedative and toxic properties of morphine, and five semi-syntheticopiates (diamorphine, dihydromorphinone, dihydrocodeine, oxymorphoneand oxycodone) have been determined by giving them, in a double-blindtrial, as pre-anaesthetic medication to a standard female population.Diamorphine and dihydromorphinone produced the best sedationwhilst dihydrocodeine was least efficient in this respect. Dihydromorphinoneand oxymorphone were markedly more toxic than the others, whilstdihydrocodeine was the least toxic drug in this group.     

STUDIES OF DRUGS GIVEN BEFORE ANAESTHESIA XIII: PENTAZOCINE AND OTHER OPIATE ANTAGONISTS

The non-addicting analgesic pentazocine (Fortral) was comparedwith the established opiate antagonists nalorphine and levallorphanwhen used in pre-operative medication in female patients. Theparent compounds phenazocine, morphine, levorphanol, and pethidinewere employed in a similar way for control purposes. In addition,the commercial preparation Pethilorfan which contains pethidineand levallorphan in a ratio of 80:1 was studied. In each comparisonthe antagonist was found to be a more effective sedative thanwas the corresponding opiate, but there was a high incidenceof dizziness and psychotomimetic effects. The latter were notmarked with low (20–40 mg) doses of pentazocine. Emeticsequelae were considered both pre- and post-operatively andthe antagonists were all less toxic than the addicting opiates,though all were worse than saline.     

STUDIES OF DRUGS GIVEN BEFORE ANAESTHESIA XI: DIAMORPHINE (HEROIN) AND MORPHINE

The pre-operative effects, influence on the course of methohexitoneanaesthesia and influence on postoperative complications ofpremedication with diamorphine 5 mg and 7.5 mg were comparedwith those following morphine 10 mg and 15 mg. The sedativeaction of diamorphine occurred earlier than that of morphineand its soporific effect was slightly more marked. Diamorphinewas found to have a shorter duration of action and this mayaccount for the higher incidence of excitatory phenomenon andmore rapid recovery from anaesthesia associated with its use.Emetic sequelae following diamorphine 5 mg and morphine 10 mgdid not differ significantly, but the increased incidence atthe higher dose was less in the case of diamorphine.     

Drug injecting in patients in New Zealand Methadone Maintenance Treatment programs: An anonymous survey

Introduction and Aims. To investigate the prevalence and nature of injecting behaviour among patients on Methadone Maintenance Treatment (MMT) programs. Design and Methods. A self‐reported questionnaire was handed to 423 patients enrolled in MMT across six clinics in the lower North Island of New Zealand. Results. A total of 151 patients responded, giving a 35.6% response rate. One hundred and twenty (79.5%) respondents reported they had injected methadone while enrolled in MMT, 84 (55.6%) had injected methadone in the last year and of those 43 (35.8%) had injected methadone in the last week. Reasons given for injecting of methadone included: rapid onset of effect, needle fixation and euphoria. Time on the methadone programme was negatively associated with ever injecting methadone [odds ratio (95% CI) 0.92 (0.85–0.99), P = 0.029] and injecting other substances [odds ratio (95% CI) 0.93(0.87–1.0), P = 0.046]. More frequent pharmacy‐observed consumption was associated with increased injecting of other substances [odds ratio (95% CI) 1.32 (1.09–1.59), P = 0.005] but not methadone. The time a person had been enrolled on the methadone programme was associated with decreased use of other substances [odds ratio (95% CI) 0.93 (0.87–1.0), P = 0.046]. Discussion and Conclusions. Many individuals on MMT continue to inject their methadone. In this sample, the frequency of injection of methadone did not correlate with prescribed dose or takeaway arrangements. The beneficial impact of time on the programme emphasises the importance of retention in treatment. It is suggested that these results also indicate a need for routine education concerning safe injecting.[Judson G, Bird R, O'Connor P, Bevin T, Loan R, Schroder M, McGrath R, Weatherall M, Moriarty H, Robinson G. Drug injecting in patients in New Zealand Methadone Maintenance Treatment programs: An anonymous survey. Drug Alcohol Rev 2009]     

STUDIES OF DRUGS GIVEN BEFORE ANAESTHESIA XVIII: THE SYNTHETIC OPIATES

The sedative and toxic properties of eleven synthetic analgesics(levorphanol, phenazocine, pentazocine, pethidine, anileridine,phenoperidine, fentanyl, methadone, dipipanone, dextromoramideand phenadoxone) have been determined by giving them, in a double-blindtrial, as pre-anaesthetic medication to a standard female population.Levorphanol produced the best sedation while phenoperidine,dipipanone and dextromoramide were also effective in calmingthe patient. Fentanyl was least efficient in this respect. Pethidineand fentanyl were the most toxic drugs while pentazocine anddipipanone showed least toxicity.     

Elevated Resting Energy Expenditure in Adolescents With Sickle Cell Anemia

Objective To assess the reliability of standard prediction equations in estimating resting energy expenditure (REE) values in adolescents with sickle cell anemia.Subjects/design Body composition and metabolic measurements were performed in 8 adolescents, aged 11 to 18 years, with homozygous sickle cell anemia. REE was measured by indirect calorimetry under standard conditions, and measurements were compared with 4 prediction formulas (Harris-Benedict, Schofield, Mayo Clinic, and Food and Agriculture Organization/World Health Organization/United Nations University). Fat-free mass was measured to assess REE per unit of actively metabolizing tissue. Fat-free mass was expressed as a mean of values obtained by densitometry, deuterium dilution, ⁴⁰K-counting, and total body electrical conductivity.Statistical analyses Repeated measures analysis of variance was performed to determine whether measured REE values and predicted values differed. The Fischer test was used to identify which predicted values differed significantly from the measured REE.Results All 4 prediction formulas significantly underestimated REE. Group mean values for the prediction formulas ranged from 83% to 89% of the measured value. REE averaged 47.7±10.0 kcal/kg fat-free mass per day, which is 30% to 50% higher than reported values in healthy adolescent populations.Conclusions These data suggest that REE is elevated in adolescents with sickle cell anemia. Standard equations used to predict REE are unreliable in these patients.Applications REE in patients with sickle cell anemia is best determined by indirect or direct measurement of energy expenditure. Clinically useful formulas to estimate REE should be developed for patients with conditions, including sickle cell anemia, where the metabolic rate may be altered.J Am Diet Assoc. 1999;99:195–199.