The teaching and organisation of clinical pharmacology in European medical schools (W.H.O. Working Group on Clinical Pharmacology)

A World Health Organisation (European Regional Office) working party has been established to review the progress of clinical pharmacology in European countries. As part of this review a questionnaire on the teaching of clinical pharmacology was sent to the Deans of all 350 medical schools in the region. Very few replies were received from U.S.S.R., Greece and Portugal and these countries' returns were not analysed further. The overall compliance rate (excluding these countries) was 82% with a figure of 84% from Western Europe and 74% from Eastern Europe. An average time of 96 h (range 0-320) was devoted to pharmacology teaching in the medical curriculum in Western Europe with 124 (0-240) h in Eastern Europe. In contrast 28 h (0-210) was devoted to clinical pharmacology teaching in Western Europe and 27 h (0-90) in Eastern Europe. On average in Western Europe each medical school had 2 individuals trained in clinical pharmacology with 1.3 posts in the subject and the figures for Eastern Europe were 2.3 and 1.1 respectively. However these figures hide a wide variance in the teaching of clinical pharmacology. Particularly in Western Europe there are a number of medical schools in Italy, Spain and the Federal Republic of Germany (FRG) where clinical pharmacology is not taught and there is a dearth of individuals trained in the subject. Every effort to encourage clinical pharmacology and its teaching should be made, particularly in these countries.

EEG and SEMG monitoring during induction and maintenance of anesthesia with propofol

Propofol has been used as IV induction (2 mg/kg) and maintenance agent (150 micrograms/kg/min and 100 micrograms/kg/min after 30 min), combined with N2O/O2 in 16 premedicated (atropine 0.5 mg, Thalamonal 2 ml IM) and mechanically ventilated patients, having ear surgery or arthroscopy. Cranial biopotentials were analysed by 2 different techniques: 1. The Anesthesia and Brain Activity Monitor (ABM Datex) providing the zero crossing frequency (ZXF) as a value for the mean frequency of the EEG signal during a considered time interval, the mean integrated voltage (MIV) as a mean value of the amplitude of the same EEG signal and the spontaneous electromyography of the frontal muscle (SEMG). 2. The EEG trend monitor (rough signal, spectral analysis (S.A.), procentual display). The EEG changes, recorded during propofol anesthesia, are comparable with both techniques. Induction is characterised by a decrease in ZXF, caused by a procentual increase in the low frequency bands (the delta band represents more than 80% of the total power). During the perfusion period an increase in the power of the alpha band (10% to 40%) and a decrease in the delta band is noticed. The ZXF regains its original value. At the end of the procedure the ZXF increases (beta band to more than 30%). A correlation was looked for between the EEG changes and the propofol blood concentrations. The higher the propofol blood concentrations, the more pronounced the low frequency bands. The appearance of beta waves or a ZXF greater than 10 Hz indicates pending arrousal.

The dissolution rate and bioavailability of hydrochlorothiazide in pellet formulations

The influence of non-active ingredients in the manufacture of pellets on in-vitro dissolution rate and on bioavailability of hydrochlorothiazide has been studied. Pellets were formulated using either microcrystalline cellulose or microcrystalline cellulose-carboxymethylcellulose sodium blends as matrix, and hydrochlorothiazide as the active ingredient. In-vitro drug release from the different pellet formulations was retarded in comparison to a conventional tablet formulation and was dependent on the nature of the non-active ingredient and, for the microcrystalline cellulose-carboxymethylcellulose sodium blend, of the dissolution medium. In-vivo bioavailability of both pellet formulations was low compared with that of the conventional tablet and the plasma concentration-time profiles did not suggest slow release.

8-Methoxypsoralen plasma levels and phototoxic effect

In 8 normal volunteers, the minimal phototoxic dose was determined at 15 min intervals up to 60 min and thereafter every 30 min up to 4 h; 8-methoxypsoralen (8-MOP) was administered as a solution and small additional doses were given during the course of the experiment, so that a more or less predictable and stable plasma concentration was obtained and maintained for about 2 h. Three of the subjects absorbed 8-MOP very rapidly, already reaching plasma concentrations above 200 ng/ml after 15 min; in the other 5, absorption was slower and comparable levels were achieved only after 30 to 90 min. In the fastest absorbers, there was a 15 to 30 min lag between reaching a high plasma level and a low MPD. In the other cases, such a delay was not seen. This suggests that the time to reach peak concentration in the skin is not influenced by changes in absorption rate: simulations based on the classical plasma concentration equations for a two-compartmental model also show this. Afterwards, the skin sensitivity decreased in most cases parallel to the plasma concentrations.

The production in high yield of N'-(4-[11C]methyl)-imipramine

A method for the routine production in high yield of N'-(4-[11C]methyl)-imipramine is presented. The label is incorporated by reaction of C-11 methyl iodide (11CH3I) upon desipramine in dimethylsulfoxide. Quaternization of the tertiary amine by 11CH3I is minimized by using an excess of desipramine. The reaction proceeds at room temperature for 10 min and the product is isolated by means of high-performance liquid chromatography (HPLC). The entire production takes only 40 min and results in a radiochemical yield of 60%. About 60 mCi of labeled product are available for medical application; the specific activity, at the time of use, is 50 mCi/mumole. The product was characterized by chromatographic and spectrometric methods.

Peritoneal pharmacokinetics of gentamicin in man

The peritoneal pharmacokinetics of gentamicin were investigated in patients on continuous ambulatory peritoneal dialysis. Gentamicin was added to the dialyzate, and gentamicin concentrations were measured repeatedly in serum and dialyzate. After administration of a single dose of gentamicin, equilibrium between serum and dialyzate levels is achieved within 24 hours; dialyzate levels of gentamicin are lower and mass transfer coefficients higher in patients with peritonitis. With chronic intraperitoneal gentamicin treatment for peritonitis, steady state serum levels around 4 to 5 mg/l are achieved and otovestibular toxicity should be feared.

The progress of patients in the European Working Party on Hypertension in the Elderly trial

792 hypertensive patients above the age of 60 have entered the double-blind multicentre trial of the European Working Party on High blood pressure in the Elderly (EWPHE). Half were treated with hydrochlorothiazide and triamterene and half were given placebo and a second capsule was given and if necessary up to 2 g of methyldopa/day. The measurements in a sample of 157 patients suggested 80-86% compliance rate. A significant blood pressure difference of 25/10 mm Hg was obtained between the groups and maintained during five years of follow-up. The increase in serum creatinine found in the actively treated group was related to the decrease in sitting systolic blood pressure. Changes in serum uric acid correlated with changes in serum creatinine both in the placebo and in the actively treated group. Fasting blood glucose changed significantly in the active treatment group. The balance between this decreased risk on the basis of the blood pressure reduction and the increase produced by the rise in blood glucose and the other treatment effects remains to be determined. The trial continues and more patients are being admitted.

Antihypertensive therapy in patients above age 60 with systolic hypertension. A progress report of the European Working Party on High Blood Pressure in the Elderly (EWPHE)

1. Although systolic blood pressure elevation is responsible for increased incidence of cardiovascular accidents in old people, the preventive benefit of lowering systolic hypertension in elderly has not been confirmed. 2. A double blind study comparing the effects of a placebo and of an active regimen (hydrochlorothiazide-triamterene with or without methyldopa) in people over 60 years with isolated systolic hypertension has been undertaken by the European Working Party on High blood pressure in the Elderly (EWPHE). 3. The actively treated group shows a lowered sitting blood pressure (-15/6 mm Hg), a mild increase of serum creatine, serum uric acid and blood glucose and a mild decrease of serum potassium after two years of treatment when compared to the spontaneous changes observed in the placebo treated group. 4. The study is continuing to evaluate if the blood pressure reduction prevents or reduces the incidence of cardiovascular accidents, although some biochemical changes were provoked by the treatment.

The combined effect of theophylline and terbutaline in patients with chronic obstructive airway diseases

Using a double-blind, cross-over design the acute bronchodilating effect of 375 mg microcrystalline theophylline, 5 mg terbutaline, a combination of both drugs and placebo was studied in 11 patients suffering from moderate to severe chronic obstructive lung disease with partially reversible airway obstruction. Plasma concentrations both theophylline and terbutaline were measured. The bronchodilation produced by oral intake of 5 mg terbutaline and 375 mg theophylline was comparable. The maximal median value of terbutaline in plasma was 4.6 ng/ml 2 h after intake of medication, followed by a decline with a double peak in some patients. The maximal median increase of FEV1 was 37% 3 h after intake of medication. The maximal median plasma level of theophylline reached 12.5 ng/ml 30 min after intake of the medication. The median maximal increase of FEV1 was 24%. One hour after intake of medication and throughout the whole test period up to 7 h, the combination of 5 mg terbutaline and 375 mg theophylline produced a significantly greater bronchodilation than each drug alone. It is concluded that 375 mg microcrystalline theophylline produced a significantly greater bronchodilation than each drug alone. It is concluded that 375 mg microcrystalline theophylline and 5 mg terbutaline produces almost equal bronchodilating activity: a combination of both drugs, however, results in further bronchodilation.

Lidocaine plasma concentrations obtained with a standardized infusion in the awake and anaesthetized dog

Lidocaine was administered intravenously on several occasions to three healthy mongrel dogs. The lidocaine treatment consisted of an infusion of 0.8 mg/kg/min over 10 min, followed by an infusion of 0.085 mg/kg/min over 3 h. This lidocaine treatment was given once in the awake state and on two other occasions the infusion was started before or during the following anaesthetic regimen: atropine-meperidine premedication, thiopental induction and maintenance nitrous oxide-methoxyflurane anaesthesia. In most instances plasma levels were somewhat higher at the end of the loading infusion (greater than 5 micrograms/ml) than subsequently, but steady-state values were obtained soon after starting the 3-h infusion. There were no striking differences between the plasma profiles and half-lives found in the three series of experiments: mean plasma concentrations of lidocaine during steady state were between 3.5 and 5.0 micrograms/ml and the half-life of lidocaine was 1 to 2 h. Signs of intoxication were not seen in any of the dogs at any stage of the procedures. It is concluded that with the loading and maintenance doses used in this study steady-state values, probably within the therapeutic range, are obtained within a few minutes. The plasma concentrations are not influenced by the anaesthetic regimen used.

Randomized trial of two beta-mimetic drugs (ritodrine and fenoterol) in acute intra-partum tocolysis

The uterine inhibitory effect and potential maternal and fetal side effects of two beta-mimetic compounds, ritodrine hydrochloride and fenoterol hydrobromide, were compared in a randomized trial. The drugs were administered by intravenous infusion to 24 healthy term nulliparous women during effective first-stage labour; each of them received fenoterol (1, 2, or 4 microgram/min) or ritodrine (100, 200, or 400 microgram/min). There was no difference between the drugs in the intensity of the uterine inhibition. However, for a similar inhibitory effect, the duration of tocolysis was longer after ritodrine. During the intrapartum and neonatal periods, neither compound induced any change in the fetal parameters investigated, and their effects on maternal parameters were comparable.

Plasma theophylline level and effect on lung function after oral and rectal administration of aminophylline

Twelve patients with partly reversible, chronic airway obstruction, according to a double blind randomized cross-over design, received on three consecutive days oral aminophylline 500 mg, a 500 mg aminophylline suppository and a placebo. The effects on ventilatory function were studied and the plasma concentration of theophylline was measured. After rectal administration, the plasma concentration of theophylline rose to 5 to 10 microgram/ml, and after oral ingestion the plasma level in most patients exceeded 10 microgram/ml. Administration of the aminophylline suppository resulted in moderate improvement in ventilatory function, and although the improvement was less pronounced than after oral administration, the use of a suppository in the treatment of patients with chronic obstructive lung disease should not be rejected.

Effects of angiotensin antagonism at rest and during exercise in sodium-deplete man

Mean intra-arterial pressure (P-), heart rate (HR), cardiac index (CI), total peripheral resistance index (TPRI), and plasma renin activity (PRA), norepinephrine (PNE), and epinephrine (PE) were estimated in five normal male subjects placed on a low-sodium diet for the previous 7 days. Subjects were studied during rest in recumbency and during intravenous infusion of either glucose or saralasin in a) recumbent position, b) sitting position on the bicycle ergometer, and c) during submaximal graded exercise. At rest recumbent saralasin induced pressure changes that were closely related to logPRA. During exercise the increase in P- was significantly lower during saralasin as compared to glucose from 110 W on, related to a greater reduction in TPRI. The increase of PRA during exercise was about three times greater with saralasin as compared to glucose, but the rises in PNE and PE were similar in both series of tests. Angiotensin II may thus have a role in the maintenance of P- in the supine sodium-deplete normal subjects, and stimulation of the renin angiotensin system during physical exercise contributes to a minor extent to the increase in P- in these conditions.

Pharmacokinetics of drugs in rabbits with experimental acute renal failure

Serum protein binding and serum levels of antipyrine, phenytoin and phenylbutazone were measured in rabbits with acute renal failure induced by uranyl nitrate. The kinetics of antipyrine are not altered in the uraemic rabbit. Serum protein binding of phenytoin and phenylbutazone is decreased and the volume of distribution of total drug is increased. The volume of distribution of free phenytoin is unchanged, that of free phenylbutazone is decreased in acute renal failure. The half-lives of phenytoin and phenylbutazone are unchanged, but the serum clearance is increased in experimental acute renal failure. The intrinsic clearance of free drug, i.e. the ability of the liver enzymes to metabolize the drug, is not altered for antipyrine, is increased for phenytoin and is decreased for phenylbutazone. It is difficult to extrapolate these data obtained in rabbits with acute renal failure to humans in chronic renal failure.

Design of a study to evaluate drug therapy of serious ventricular rhythm disturbances after an acute myocardial infarction

A study was designed to investigate whether long-term use of aprindine can prevent sudden death from primary ventricular fibrillation. Patients with a proven recent myocardial infarction and malignant ventricular arrhythmias occurring late after the acute episode were asked to participate in a 1-yr, double-blind, randomized, placebo-controlled trial to suppress the rhythm disturbances observed on an ambulatory electrocardiogram. Particular care was taken to monitor drug adherence. Arrhythmia detection by ambulatory electrocardiography was used to assess drug efficacy; side-effects establish the maximum tollerated dose for each individual patient. Aprindine was therefore used under optimal circumstances. An interactive computer system served as a data base and provided the investigators and the monitoring committee with all the information required for a proper evaluation of the progress of the study.

Serum binding of quinidine in experimental acute renal failure

Quinidine serum binding is increased in some patients with acute renal failure, but in animals with renal failure conflicting results were published. Therefore, serum binding of quinidine, papaverine and phenylbutazone was studied by equilibrium dialysis in rabbits and rats with acute renal failure induced either by injection of uranyl nitrate or ligation of the ureters. From the results it appears that, in animals, quinidine binding changes are different according to the model used for induction of the renal failure, regardless of the species studied. After ligation of the ureters, lipoprotein concentration increases, but the meaning of this increase for increased serum quinidine binding is not clear.