Articles: anesthetics.
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Acta Anaesthesiol Scand · Oct 1988
Alterations in the pharmacokinetic properties of amide local anaesthetics following local anaesthetic induced convulsions.
The comparative pharmacokinetic properties of lidocaine, bupivacaine, etidocaine and mepivacaine were investigated in convulsing and non-convulsing dogs. The same dose of a given local anaesthetic was administered as either a 30-s intravenous (IV) bolus to produce convulsions or as a 15-min IV infusion producing no convulsions. Derived pharmacokinetic data were found to be different in convulsing and non-convulsing animals. ⋯ Overall, the most profound effects of convulsions on pharmacokinetic data were seen with mepivacaine. Convulsions were associated with increases in heart rate ranging from 117% (lidocaine, P less than 0.05) to 129% (mepivacaine, P less than 0.05), increases in cardiac output ranging from 78% (mepivacaine) to 232% (bupivacaine, P less than 0.05) and increases in mean arterial pressure ranging from 45% (lidocaine, P less than 0.05) to 80% (bupivacaine, P less than 0.05). The results suggest that when local anaesthetic-induced seizures occur in man, it cannot be assumed that these drugs will be distributed and eliminated as predicted by intravenous infusion of non-toxic doses.
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J Am Podiatr Med Assoc · Oct 1988
Randomized Controlled Trial Comparative Study Clinical TrialDigital perfusion with tibial nerve block. A comparative study of eight local anesthetics.
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Acta Anaesthesiol Scand · Oct 1988
Comparative StudyPrimary evaluation of the local anaesthetic properties of the amino amide agent ropivacaine (LEA 103).
The local anaesthestic properties of 1-propyl-2',6'-pipecoloxylidide, a congener of mepivacaine and bupivacaine, and its enantiomers were compared in animals. The (S)-enantiomer (ropivacaine, LEA 103) produced a longer duration of sciatic nerve block and infiltration anaesthesia than the racemate and the (R)-form. Ropivacaine and bupivacaine were equally potent in terms of block of evoked action potential in vitro and minimum effective concentration in vivo. ⋯ Ropivacaine was less toxic (i.v. and s.c. LD50-values) than bupivacaine but more toxic than lidocaine, and produced only weak local irritation. Due to a combination of interesting local anaesthetic properties and relative safety including cardiotoxic potential, we consider ropivacaine a candidate for further studies.
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Anaesthesia was induced with propofol 2.5 mg kg-1 followed by suxamethonium 1.5 mg kg-1 in six young healthy females undergoing laparoscopy. ECG was monitored continuously. ⋯ The bradycardia may be prevented by premedication with atropine. In contrast to thiopentone, propofol apparently lacks central vagolytic activity and may exert a central vagotonic effect which can exaggerate the muscarinic effects of suxamethonium.
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The effects of methohexitone, ketamine, Althesin and droperidol on the peripheral vagal transmission to the heart were studied in decerebrate cats by evaluating the influences of the drugs on the heart rate responses to vagal electrostimulation and the injection of acetylcholine i.v. The sites of the peripheral vagal transmission (vagal ganglia and sino-atrial pacemaker cells) were reached by the application of the drugs to the pericardial space. The bradycardia in response to vagal electrostimulation was attenuated by Althesin (2.1 x 10(-4)-3.3 x 10(-3) mol litre-1; expressed as the concentration of alphaxalone), ketamine (2.9 x 10(-4)-4.6 x 10(-3) mol litre-1) and droperidol (2.6 x 10(-5)-6.6 x 10(-4) mol litre-1) in a concentration-dependent manner, but not influenced by methohexitone (2.8 x 10(-4)-4.4 x 10(-3) mol litre-1). The bradycardia-attenuating effects were probably caused by an atropine-like action since the heart rate responses to the injection of acetylcholine i.v. were also attenuated by the same three drugs.