Cyclopropane Norepinephrine

SNRIs are chemically unrelated to each other. Venlafaxine was discovered in the process of evaluating chemicals that inhibit binding of imipramine. Venlafaxine s in vivo effects are similar to those of imipramine but with a more favorable adverse-effect profile. All SNRIs bind the serotonin (SERT) and norepinephrine (NET) transporters, as do the TCAs. However, unlike the TCAs, the SNRIs do not have much affinity for other receptors. Venlafaxine and desvenlafaxine are bicyclic compounds, whereas duloxetine is a three-ring structure unrelated to the TCAs. Milnacipran contains a cyclopropane ring and is provided as a racemic mixture. 

E. Chloral hydrate overdose and cyclopropane and halogenated or aromatic hydrocarbon solvents and anesthetics may enhance myocardial sensitivity to arrhythmogenic effects of norepinephrine. 

Patients anaesthetised with inhalational anaesthetics (particularly cyclopropane and halothane, and to a lesser extent desflurane, enflurane, ether, isoflurane, methoxyflurane, and sevoflurane) can develop cardiac arrhythmias if they are given adrenaline (epinephrine) or noradrenaline (norepinephrine), unless the dosages are very low. Children appear to be less susceptible to this interaction. file addition of adrenaline to intrathecal tetracaine enhances the sedative effects of propofol. 

Two studies report on the interaction of A -THC with anesthetics. The minimum alveolar anesthetic (MAC) requirements for cyclopropane in rats and halothane in dogs were significantly decreased by pretreatment with A -THC. Analgesia, sedation and prolonged barbiturate sleeping time after acute A -THC injection may reflect the potential additive anes-thetic-like action of the drug. Alternatively, drvigs that deplete norepinephrine in the CNS decrease halothane MAC . 

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