PubMed Health⌕ Search

Biomedical subjects

B J Pleuvry

Publications and source records attributed to B J Pleuvry.

At least 55 records · Page 3Linked to original sources
PubMed1982

Double-blind comparison of the respiratory and sedative effects of codeine phosphate and (+/-)-glaucine phosphate in human volunteers.

1 Two antitussive agents (+/-)-glaucine phosphate and codeine phosphate have been compared with placebo with respect to ventilation, ventilatory response to carbon dioxide, pulse, blood pressure, digit symbol substitution, sedation score and the Zahlen-Verbindung test performance in ten healthy volunteers (22-36 years). The study was double-blind and the two doses of each antitussive agent and the placebo were administered as a syrup. 2 Both codeine phosphate and (+/-)-glaucine phosphate displaced the ventilatory response to carbon dioxide to the right. 3 The effect of codeine phosphate on the ventilatory response to carbon dioxide was not dose dependent: 30 mg produced greater effects than the 60 mg dose. 4 Only the highest dose of (+/-)-glaucine phosphate (60 mg) caused respiratory depression and this was associated with sedation and decreased performance in the digit symbol substitution test. 5 Neither antitussive agent had significant effects upon pulse or blood pressure and codeine phosphate had no detectable sedative activity.

Adult↗
PubMed1982

Ventilatory and cardiovascular effects of BHT 933 in volunteers.

In 12 healthy volunteers BHT 933 in doses of 5 and 10 mg had minimal effects on ventilation, a small fall in total volume occurred with the highest dose. BHT 933 (5 mg) reduced both systolic and diastolic blood pressure, but had little effect on autonomic reactivity tests, whereas the 10 mg dose reduced the response to these tests. Both doses of BHT 933 caused marked sedation. It is concluded that 5 mg BHT 933 orally presents the most suitable profile of activity for further studies into its usefulness as an anti-tussive and antihypertensive.

Adult↗
PubMed1981

Antagonism of the respiratory effects of alfentanil and fentanyl by naloxone in the conscious rabbit.

The ability of naloxone to antagonize the respiratory effects of alfentanil, a new short-acting analgesic, was studied in the rabbit. The results were compared with naloxone antagonism of fentanyl. Minute volume and respiratory frequency, and pH, PCO2 and standard bicarbonate of arterialized venous blood were measured. Naloxone was more effective as an antagonist to alfentanil than as an antagonist to fentanyl.

Alfentanil↗
PubMed1981

Comparison of the respiratory effects of ICI 35 868 and thiopentone in the rabbit.

The effects of thiopentone and ICI 35 868 on minute volume, respiratory frequency, tidal volume and arterialized venous PCO2, pH and standard bicarbonate have been compared in the rabbit. ICI 35 868 has two to three times the potency of thiopentone, but equivalent anaesthetic doses cause similar decreases in minute volume. ICI 35 868 decreased tidal volume to a greater extent than thiopentone. Whilst the time courses of the two drugs were similar in most respects, thiopentone produced a more prolonged increase in PCO2. This was accompanied by an increase in standard bicarbonate which was not seen in rabbits treated with ICI 35 868.

Anesthesia, Intravenous↗
PubMed1980

Respiratory effects of a new opiate analgesic, R 39209, in the rabbit: comparison with fentanyl.

The respiratory effects of R 39209, a new short-acting analgesic, were studied and compared with those of fentanyl, in the rabbit. Minute volume, respiratory frequency and pH, PCO2 and standard bicarbonate of arterialized venous blood were measured. R 39209 had an earlier peak effect and shorter duration of action then fentanyl, but otherwise the respiratory effects of the two-drugs were similar. Fentanyl was between 2 and 3.5 times more potent than R 39209. Repeated doses of R 39209 produced reproducible peak effects even when only 10 min was allowed between administrations.

Alfentanil↗
PubMed1980

Effect of droperidol on dopamine-induced increase in effective renal plasma flow in dogs.

The interaction between small doses of dopamine and droperidol on effective renal plasma flow was studied in dogs. Small doses of dopamine are known to produce renal vasodilatation by a dopaminergic mechanism and droperidol, a selective dopamine antagonist used in neuroleptanaesthesia, may attenuate this response. Effective renal plasma flow was measured non-invasively using 125I-hippuran. A 20-min infusion of dopamine 2 microgram kg-1 min-1 significantly enhanced effective renal plasma flow (mean increase of 16%; P < 0.05) in anaesthetized dogs. This effect was abolished (mean decrease 6.6%) by droperidol 0.2 mg kg-1 administered at the commencement of anaesthesia. It is concluded that droperidol reduces the renal vasodilatation induced by dopamine in anaesthetized dogs.

Animals↗
PubMed1980

Respiratory and psychological effects of oral temazepam in volunteers.

In a double-blind comparison with placebo the time-course of the effects of temazepam 40 mg and 20 mg on breathing, arterial pressure, oral temperature, cognitive function, psychomotor performance and subjective observations have been examined in 12 healthy volunteers. Temazepam 40 mg caused significant displacement of the ventilatory response to carbon dioxide 1 h after administration and a decrease in oral temperature 2 h after administration. Deficits in cognitive function were still apparent 1.5 and 2.5 h after administration and psychomotor performance did not equal control at 3.5 h. However, most subjects felt normal 2.5-3 h afterwards. Temazepam 20 mg had significant effects on cognitive function and psychomotor performance only during the 1st hour after administration.

Administration, Oral↗
PubMed1980

A sex difference in the effects of oral codeine and promethazine on the ventilatory response to carbon dioxide in human volunteers.

1 Interactions between codeine and promethazine have been studied in male and female volunteers, measuring ventilation, end tidal PCO2, ventilatory response to CO2, pulse and blood pressure. 2 The effects of codeine on the above measurements have been compared in subjects who habitually smoke cigarettes and non smoking subjects. 3 Codeine displaced the ventilatory response to CO2 to the right and increased end tidal PCO2 in female subjects but not in males. 4 Promethazine plus codeine displaced the ventilatory response to CO2 to the right in male subjects but tended to reduce the response to codeine in females. 5 The slope of the ventilatory response to CO2 was significantly steeper in smokers and codeine caused significant reductions in slope in these subjects.

Adult↗
PubMed1980

The effects of nefopam on blood acid-base status in the rabbit: interactions with morphine in the mouse and rabbit.

Nefopam, a non-narcotic analgesic, had only minor effects upon the blood pH, PCO2 and standard bicarbonate of the conscious rabbit. In contrast morphine caused a dose-dependent increase in PCO2 and standard bicarbonate. When nefopam was administered in conjunction with morphine (2.5 mg kg-1 and 1 mg kg-1 i.v. respectively) the increase in PCO2 was greater than with morphine alone. Nefopam also increased the antinociceptive and respiratory frequency depressant effects of morphine in the mouse.

Acid-Base Equilibrium↗
PubMed1979

An in vitro study of the effects of calcium on the cardiovascular actions of thiopentone, althesin and ketamine in the rat.

The actions of three intravenous anaesthetics, Althesin, thiopentone and ketamine have been compared on the rat isolated atria and portal vein. Although the three anaesthetics had grossly similar actions on the two preparations. i.e. depression of atrial rate and depression of the amplitude of myogenic activity in the portal vein, there were enough differences to suggest that they produced their effects by different mechanisms. These differences were particularly obvious in interactions with noradrenaline and the effects of changes in calcium ion concentration on the concentration effect relationships for the agents on the atria and portal vein. Generally Althesin was unaffected by changes, but in qualitatively different ways.

Alfaxalone Alfadolone Mixture↗
PubMed1978

A study of the enhanced toxicity of doxapram in rodents treated with narcotic analgesics.

It has been shown in both mice and rats that the LD50 value for doxapram is reduced in rodents treated with narcotic analgesics. In both species the site of the toxic interaction appears to be the cardiovascular system. Doxapram alone, in sub-lethal doses, appears to cause conduction defects in the heart and this action of doxapram is increased in rodents treated with morphine. The enhancement of the toxicity of doxapram by morphine appears to involve an action in the central nervous system probably not related to respiratory depression.

Analgesics, Opioid↗
PubMed1978

A study of naloxone and doxapram as agents for the reversal of neuroleptanalgesic respiratory depression in the conscious rabbit.

The effectiveness of naloxone and doxapram in reversing the respiratory depressant actions of fentanyl and droperidol in the rabbit has been examined. Both drugs did not reverse fully the depression of respiratory frequency produced by the neuroleptanalgesic agents. Doxapram also failed to reverse fully the depression of minute volume produced by fentanyl and droperidol, although naloxone was adequate in this respect. However, analysis of arterialized venous blood showed that both naloxone and doxapram not only prevented the increase in PCO2 caused by fentanyl and droperidol, but caused also a significant decrease. A reduction in PCO2 was seen also when either naloxone or doxapram was given to untreated rabbits. With doxapram this appeared to be a result of pure respiratory stimulation. Naloxone also produced a reduction in standard bicarbonate.

Animals↗
PubMed1977

Interactions between morphine and doxapram in the rabbit and mouse.

Certain actions of doxapram, administered alone and in combination with morphine, have been examined in the rabbit and the mouse. Single doses of doxapram were capable of stimulating respiration in both species. There was an increase in tidal volume in the rabbit and an increase in respiratory rate in the mouse. In both species the duration of action of single doses of doxapram was less than 15 min. In morphine-treated rabbits and mice single doses of doxapram affected neither the time course nor the intensity of the respiratory depression. In the rabbit repeated doses of doxapram did not produce tachyphylaxis with respect to the effect on tidal and minute volumes, and effectively reversed the respiratory depressant actions of morphine. The usefulness of this action must be balanced against the enhanced toxicity of doxapram observed in morphine-treated mice.

Animals↗
PubMed1977

In vitro study of interactions between i.v. anaesthetics and neuromuscular blocking agents.

The interactions of four anaesthetic drugs (ketamine, propanidid, Althesin and methohexitone) with two neuromuscular blocking agents (suxamethonium and pancuronium) have been investigated. On the isolated rat phrenic nerve-diaphragm preparation, all the anaesthetic drugs examined potentiated suxamethonium more than they potentiated pancuronium. The anticholinesterase agent, ecothiopate, had no significant effect on the potentiation of suxamethonium caused by the anaesthetic drugs. At low concentrations the anaesthetic drugs increased the twitch tension elicited by stimulation of the phrenic nerve, whilst at high concentrations this potentiation was followed by blockade of neuromuscular transmission. With the exception of Althesin, all the anaesthetics decreased the sensitivity of the frog rectus preparation to acetylcholine. The possible sites and mechanisms of these interactions are discussed.

Acetylcholine↗
PubMed1977

A sex difference in the interaction between promethazine and morphine in the mouse.

The effects of promethazine on the antinociceptive and respiratory actions of morphine have been examined in the mouse. Moderate doses of promethazine (5 and 10 mg kg-1) potentiated morphine's action in male mice but inhibited it in female mice. Gonadectomy abolished the interaction between promethazine and morphine in both sexes, although the intensity and duration of morphine's activity was greatly enhanced in these mice. Replacement of oestradiol in ovariectomized mice restored morphine's activity to intact female control values. However, interactions between promethazine and morphine required progesterone, as well as oestradiol, replacement to obtain results approaching those obtained in intact female mice.

Animals↗