The exact site of mechanisms of action of inhalation anesthetics is not certain but possible sites are macroscopic (CNS-brain), microscopic (axons and synapses) and molecular (pre- and postsynaptic membranes). Hence, the possible mechanisms of action of inhalation anesthetics is varied: a) Multiple receptor sites b) Motor inhibition at spinal cord level c) Many neurotransmitters are […]
The phencyclidine derivatives Ketamine anesthetic is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist. It produces “dissociative anesthesia”, characterized by evidence on the EEG of dissociation between the thalamo-cortical and limbic systems and a cataleptic state in which the eyes remain open with a slow nystagmic gaze. The patient becomes noncommunicative with an apparent wakefulness state. It
Some of the Ketamine effects discussed here. Ketamine does not increase the intraocular pressure (lOP) in routine analgesic doses. Even after the IM injection of 8 mg/kg, ketamine doses not raise lOP. However, in an: other study, in children anaesthetized with halothane, ketamine demonstrated a dose-dependent effect on lOP. A dose of 6 mg/kg IM
For the phenobarbital metabolism the binding of thiopentone in human serum is about 85% and remarkably constant over the concentration range between 4 and 80 micrograms/mL. The higher percentage of protein binding occurs at lower plasma concentrations of thiopental In phenobarbital metabolism . The percentage binding increases with increasing pH from approximate 75% at pH
There are several uses of barbiturates . Thiopental sodium is used as (1) the sole anesthetic agent for brief (15 minute) procedures, (2) for induction of anesthesia prior to administration of other anesthetic agents, (3) to supplement regional anesthesia, (4) to provide hypnosis during balanced anesthesia with other agents for analgesia or muscle relaxation, (5)
Propofol exhibits dose-dependent effects on memory. Infusions of propofol amnesia for conscious sedation produce concentrations below those required for consistent amnesia. In the study by Matsuki et al. Propofol and midazolam did not differ in amnesic effects to non-invasive stimuli. However, for invasive stimuli, midazolam showed a stronger amnesic effect at the moderate sedation level,
Pain with propofol injection occurs in majority of patients. Propofol injection pain can be reduced by the following methods explained here. Propofol causes pain or discomfort on injection in 28% to 90% of awake patients. A number of techniques have been tried for minimizing propofol injection pain with variable results. The propofol injection pain decreases
Etomidate shortens the onset time of the neuromuscular block with vecuronium. This etomidate drug interactions enhances the bradycardia induced by vecuronium. Miller’s anesthesia says the following about etomidate drug interactions – The specific endocrine effects manifested by etomidate are a dose-dependent reversible inhibition of the enzyme 11β-hydroxylase, which converts 11-deoxycortisol to cortisol, and a relatively minor
The ideal neuromuscular blocker drugs (NMB) would be rapid in onset, have a predictable offset, be nontoxic, lack deleterious cardiovascular or autonomic effects, undergo a defined means of metabolism and excretion preferably independent of end-organ function, and be inexpensive. Many of these characteristics are found in clinically available drugs like cisatracurium. To briefly review, neuromuscular
Oral transmucosal etomidate produces dose-related increases in sedation and clinically significant serum concentrations. Animal studies documented etomidate as highly permeable through the buccal mucosa with rapid onset and offset suggesting that oral transmucosal etomidate might be useful when brief mild to moderate sedation with rapid recovery is desirable. Oral transmucosal etomidate exhibited linear pharmacokinetics with
