Intravenous anaesthetic agents

It is a new intravenous anaesthetic agent with poor analgesic property. It has a briefer duration of action than thiopentone. It produces little cardiovascular and respiratory depression. A single intravenous dose produces loss of consciousness within 10 seconds and a state of anaesthesia. 

The ideal intravenous anaesthetic agent Mechanism(s) of intravenous anaesthesia Pharmacokinetics and metabolism Rapidly acting intravenous anaesthetics Non-barbiturate intravenous anaesthetics Slower-acting intravenous anaesthetics Other drugs INTRODUCTION... 

Table 4.2 Physical and pharmacological properties of the ideal intravenous anaesthetic agent...

The most commonly used barbiturates are thiopentone [5-ethyl-5-(l-methylbutyl)-2-thiobarbituric acid], methohexitone [l-methyl-5-allyl-5-(l-methyl-2-pentynyl) barbituric acid], and thiamylal [5-allyl-5-(l-methylbutyl)-2-thio-barbituric acid]. Thiamylal is slightly more Table 4.3 Incidence of life-threatening hypersensitivity reactions to intravenous anaesthetic agents... 

Table 4.5 Main properties of intravenous anaesthetic agents...

Thiopentone, given as a bolus, causes a reduction in arterial blood pressure, direct myocardial depression, vasodilatation (including venodilatation), and an increase in heart rate. In common with other intravenous anaesthetic agents, these effects are due to both a direct... 

If a (3-adrenoceptor antagonist is administered prior to sufficient ol-radrenoceptor blockade, a hypertensive episode may be precipitated with cardiac failure and pulmonary oedema. Most intravenous anaesthetic agents have been used safely, but ketamine is contraindicated. Sodium nitroprusside can be used to achieve arteriolar dilation. Esmolol, a pi-selective antagonist with very short duration of action, is administered intravenously to prevent cardiac arrhythmias intra-operatively. After tumour removal, volume administration should be aggressive to maintain haemodynamic stability, and a noradrenaline infusion may be required. 

Kitayama M, Hirota K, Kudo M, Kudo T, Ishihara H, Matsuki A. Inhibitory effects of intravenous anaesthetic agents on K (+)-evoked glutamate release from rat cerebrocortical slices. Involvement of voltage sensitive Ca (2+) channels and GABA (A) receptors. Naunyn Schmiedebergs Arch Pharmacol. 2002 366 246-253. 

INTRAVENOUS ANAESTHETICS (e.g. thiopentone sodium, propofol) BETA-BLOCKERS Risk of severe hypotensive episodes during induction of anaesthesia (including patients taking timolol eye drops) Most intravenous anaesthetic agents are myocardial depressants and vasodilators, and additive 1 BP may occur Monitor BP closely, especially during induction of anaesthesia... 

Note. For a review of the pharmacokinetics of intravenous anaesthetic agents see P. Duvaldestin, Clin. Pharmacokinet., 1981,6,61-82. 

Pharmacokinetic studies of intravenous anaesthetic agents provide useful information for comparative purposes. Following the intravenous injection of a... 

Dundee JW (1976) Hypersensitivity to intravenous anaesthetic agents. Br J Anaesth 48 57-58... 

Fisher M (1977) Hypersensitivity to intravenous anaesthetic agents. Br J Anaesth 49 87-88 Frand UI, Chang SS, Williams MH Jr (1972a) Heroin-induced pulmonary edema. Sequential studies of pulmonary function. Ann Intern Med 77 29-35 Frand UI, Chang SS, Williams MH Jr (1972 b) Methadone-induced pulmonary edema. Ann Intern Med 76 975-979... 

Watkins J., Udnoon, S., Appleyard, T. N. and Thornton, J. A. (1976) Identification and quantitation of hypersensitivity reactions to intravenous anaesthetic agents. Brit. J. Anaesth., 48, 457. 

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