Interdisciplinary teaching. A survey of CNM participation in medical education in the United States.

Nurse-midwives have participated informally in the education of medical students and residents for many years, yet little is known about their formal involvement in medical education. A two-part survey was conducted to investigate the extent and characteristics of nurse-midwifery participation in medical education in the United States. The initial questionnaire was sent to every department of obstetrics and gynecology chair listed in the directory of the Association of Professors of Gynecology and Obstetrics and addressed the use of certified nurse-midwives (CNMs) as educators within their respective departments. A subsequent questionnaire was distributed to CNMs participating in medical education and addressed their demographic characteristics, roles within the medical school faculty, and attitudes regarding work in medical education. More than one half (54%) of U.S. allopathic medical schools are formally using CNMs as educators, with the strongest involvement reported in the West and Northeast. Nearly as many CNM respondents are participating in the education of family medicine residents (57%) as in obstetrics and gynecology (59%). Most CNMs (93%) involved in medical education are also involved in nurse-midwifery education. Eighty percent of CNM respondents perceived congruency between educating student physicians and their philosophy of nurse-midwifery practice.

The effect of an antacid and food on the absorption of cimetidine and ranitidine.

The effect of varying doses of a liquid antacid preparation containing magnesium hydroxide, aluminum hydroxide and simethicone on the absorption of the H2-receptor antagonists, cimetidine and ranitidine, was determined in 2 groups of 11 volunteers; one group fasted and one group fed a standardized breakfast. The antacid alone caused a significant decrease in the AUC of cimetidine (24%). Similarly, concomitant antacid caused a 59% decrease in the AUC of ranitidine. There were no effects on any of the other pharmacokinetic parameters examined. The absorption of both drugs was similar in fasted and fed volunteers, but in the fed volunteers the antacid did not produce the decrease in AUC seen in the fasted volunteers. These data suggest that H2-receptor antagonists should not be taken at the same time as antacids.

Studies on the mechanisms of action of activated charcoal on theophylline pharmacokinetics.

Oral administration of repeated doses of activated charcoal to volunteers and dogs significantly increased the systemic clearance of intravenously administered theophylline and decreased its elimination half-life. This effect is most likely to be due to theophylline entering the gut and being adsorbed onto the charcoal. The mechanism by which intravenously administered theophylline enters the gut has been examined. Its biliary excretion after intravenous administration to patients with T-tube biliary drainage accounted for 0.28% of the dose and a similarly small biliary excretion was found in dogs. In the latter total biliary diversion had no effect on the clearance or half-life of theophylline after intravenous administration. In two dogs the theophylline content of jejunal aspirate was comparable with that of simultaneously withdrawn venous plasma samples. These results suggest that the presence of charcoal in the gut represents a sink adsorbing theophylline entering the lumen by diffusion across the intestinal wall, and by this mechanism it increases clearance of the drug even after intravenous administration.

The effects of age and chronic liver disease on the elimination of temazepam.

The pharmacokinetics of the newer 1, 4 benzodiazepine temazepam were evaluated in 16 healthy subjects aged 18-92 years and in 15 cirrhotic patients, to ascertain the effect of ageing and liver disease. The data were analysed both by classic two compartment and by non-compartmental methods. The mean elimination half-life in the control subjects was 15.5 h, considerably longer than previous estimates. No correlation was found between age and pharmacokinetic parameters. The cirrhotic group showed no statistically significant difference in the pharmacokinetic parameters nor in the urinary recovery of the dose from the control group. Temazepam plasma protein binding was assessed in a second group of 9 cirrhotics of similar severity to the main group and in matched controls. When these binding data were applied to the mean clearance data, a modest although not statistically significant, reduction in free drug clearance was observed in the cirrhotic group. This study adds further support to the observation that drugs which undergo ether glucuronidation have normal elimination patterns in patients with liver disease. Temazepam may prove to be a useful hypnotic sedative in patients with liver disease.

Decreased oral warfarin clearance after ranitidine and cimetidine.

Oxidative metabolism inhibition of a number of drugs by cimetidine has been attributed to its imidazole ring, a hypothesis that has been supported by reports that ranitidine does not affect drug metabolism despite being five times as potent as cimetidine as an H2-receptor antagonist. In five healthy subjects ranitidine at 150 mg twice daily induced a 27% fall in apparent oral warfarin clearance. In the same subjects cimetidine at 1 gm/day induced a 36% decrease in warfarin clearance. In two of the subjects the experiment was repeated after giving 750 mg ranitidine per day and in two other subjects after 200 mg cimetidine twice daily. In both instances there was a stepwise fall in warfarin clearance with increasing doses. The data indicate that interference with drug metabolism by H2-receptor antagonists is not confined to cimetidine but that on a molar basis ranitidine and cimetidine are roughly equivalent in inhibiting warfarin clearance and that the effects are related to dose.

Use of single doses and rapid sampling to detect interactions with cimetidine.

In this study the well-established interaction between cimetidine and theophylline has been demonstrated using only a single dose of cimetidine. Eleven healthy subjects were given a 30 min infusion of theophylline on two separate occasions and plasma levels were monitored at frequent intervals. During one of the studies, a single 400 mg oral dose of cimetidine was given after collection of the 3 h sample. After normalisation of the control and test curves, a deflection was apparent in the test theophylline elimination curve in 9 out of 11 subjects. This method may provide a rapid screening method to detect such interactions.

Ranitidine does not affect chlormethiazole or indocyanine green disposition.

Cimetidine has been shown to inhibit hepatic mixed-function oxidase activity and to lower hepatic blood flow. It is not known whether these effects are related to its H2-receptor antagonism or to its intrinsic structure. Ranitidine is a more potent H2-receptor antagonist and differs structurally from cimetidine. In our study, ranitidine, 150 mg twice daily, had no effect on oral or systemic clearance of chlormethiazole, a sedative with a high clearance, and no effect on indocyanine green elimination.

High-performance liquid chromatographic determination of clomiphene using post-column on-line photolysis and fluorescence detection.

A method has been developed for the extraction and quantitation of the ovulatory stimulant drug clomiphene from plasma. The cis- and trans-isomers were separated by normal-phase chromatography using chloroform-methanol as the mobile phase. After eluting from the column, the clomiphene was passed through a PTFE photolysis coil irradiated by a powerful UV lamp, resulting in conversion of the isomers to highly fluorescent species. The derivatised material was then detected using a fluorescence spectrometer. Use of this method enables a substantial improvement of sensitivity over UV detection and has permitted the measurement of plasma clomiphene levels in patients receiving clomiphene therapy.