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Biomedical subjects

J K Lilburn

Publications and source records attributed to J K Lilburn.

10 recordsLinked to original sources
PubMed1979

Comparison of the actions of diazepam and lorazepam.

Diazepam and lorazepam differ in potency and in the time-course of their action. As a sedative, diazepam 10 mg is equivalent to lorazepam 2-2.5 mg. Diazepam is better absorbed after oral than after i.m. administrations but this does not apply to lorazepam. The clinical effect and amnesia begin more rapidly with diazepam, but last longer following lorazepam. Lorazepam is more effective than diazepam in blocking the emergence sequelae from ketamine. Lorazepam i.v. is followed by a lesser frequency of venous thrombosis.

Amnesia↗
PubMed1978

Plasma lorazepam levels. A study following single dose administration of 2 and 4 mg by different routes.

Plasma lorazepam levels were studied following single doses of 2 mg and 4 mg in patients and volunteers. There was a slightly more rapid uptake of drug following deep intramuscular injection than when taken by mouth. Plasma levels declined rapidly following intravenous injection (t1/2 of approximately 2-3 hours). Two hours after giving the drug the plasma levels were similar irrespective of the route of administration. The second phase decline was very slow and one third of the peak concentration was still in the blood at 24 hours.

Administration, Oral↗
PubMed1978

Attempts to attenuate the cardiostimulatory effects of ketamine.

In an attempt to attenuate the cardiostimulatory effects of ketamine, a number of drugs were given individually, or in combination, to fit adults undergoing body surface operations, either before or aftera ketamine induction of 1 mg kg-1 followed by an infusion of 1 mg ml-1. Of these, practolol, phentolamine, practolol-phentolamine, phentolamine-practolol, promethazine, hexamethonium, procainamide and verapamil were unacceptable. Labetalol, in doses of 0.5 mg kg-1 and 1.0 mg kg-1, proved to be the most promising drug and is worthy of further study.

Adult↗
PubMed1978

Attempted reduction of the cardiostimulatory effects of ketamine by labetalol.

Labetalol, a new antihypertensive agent with alpha and beta-adrenoceptor blocking properties was given to five series of patients anaesthetised with a ketamine infusion. in an attempt to reduce the cardiostimulatory effects of ketamine. It proved very effective in controlling the chronotrophic action of ketamine but was unreliable in controlling the rise in blood pressure. In doses of 1.0 mg kg-1 given with tubocurarine, it was not without side effects.

Adolescent↗
PubMed1978

Ketamine sequelae. Evaluation of the ability of various premedicants to attenuate its psychic actions.

The ability of a number of drugs to abolish the emergence delirium and unpleasant dreams which follow anaesthesia induced with 2 mg/kg ketamine was studied. These included three benzodiazepines, droperidol and 'neurolept' combinations and four commonly-used premedicants. When given intravenously 10 min before induction of anaesthesia flunitrazepam and lorazepam gave best results. In a subsequent study, these two benzodiazepines and diazepam were given intravenously 30-40 min before induction of anaesthesia. There was no doubt that 4 mg lorazepam gave the greatest protection and is worthy of further study in this respect.

Analgesics, Opioid↗
PubMed1978

Ketamine infusions. Observations on technique, dosage and cardiovascular effects.

A continuous infusion of ketamine, following an initial dose of 1 mg/kg, has been used as sole anaesthetic in over 200 adult patients. The pre-operative use of 4 mg lorazepam has made this acceptable with respect to emergence sequelae and dreams. The technique can be used with neuromuscular blocking drugs and controlled ventilation with air, but here pancuronium is best avoided because of excessive tachycardia and hypertension. Hypertonus was the main problem encountered in the non-relaxant cases. The amount of ketamine required for anaesthesia has been analysed in detail and recommendations on dosage are given. The cardiovascular effects have also been analysed in detail. There is a need for a similar investigation to be carried out in circumstances where inhalation agents are not available and where there is a shortage of anaesthetists.

Administration, Oral↗
PubMed1977

Studies of drugs given before anaesthesia XXVI: lorazepam.

Lorazepam has been studied as preanaesthetic medication given by mouth, i.m. and i.v. Sediation and side-effects and the incidence of anterograde amnesia in patients having a standard operation under methohexitone-nitrous oxide-oxygen anaesthesia were assessed. In a preliminary study of three i.m. (2-, 4- and 8-mg) and six oral (1-,2-,2.5-,4-,5- and 8-mg) doses, the optimum dose was found to be 4 mg for patients with an average weight of 60 kg. This dose was studied in detail when given by all three routes and compared with the commercially available 2.5- and 5-mg tablets. Even when given i.v., there was a delay of 30-40 min in the onset of maximum sedative effect and drowsiness persisted for at least 4 h. Although the onset of action by i.m. injection was slightly faster than when the drug was given by mouth this advantage was more than offset by the high frequencies of pain at the site of injection and restlessness which persisted for 20-40 min. Oral lorazepam in doses of 2.5-5.0 mg was a reliable, effective sedative which could be recommended for routine preanaesthetic medication, provided rapid recovery was not essential. Its soporific effect was accompanied by an appreciable incidence of anterograde amnesia.

Administration, Oral↗
PubMed1977

Estimation of plasma lorazepam by gas-liquid chromatography and a benzene extraction.

Plasma lorazepam can be easily and reliably estimated using a simple single stage benzene extraction and gas-lizuid chromatography with flunitrazepam as the internal standard. Reproducible results within the clinical range of plasma levels were obtained. This method permits the extraction and chromatographing of 40 samples in approximately 7 1/2 hours.

Anti-Anxiety Agents↗