Neostigmine mechanisms

Anticholinesterase agents can be employed in the treatment of adynamic ileus and atony of the urinary bladder, both of which may result from surgery. Neostigmine is most commonly used, and it can be administered subcutaneously or intramuscularly in these conditions. Cholinesterase inhibitors are, of course, contraindicated if mechanical obstruction of the intestine or urinary tract is known to be present. 

In time and as the result of repeated administration of succinylcholine, depolarization no longer promotes the formation of the neuromuscular blockade (desensitization). The blockade is then changed in character and becomes antagonized by neostigmine through the operation of an ill-defined mechanism that is very distinct from competitive blockade. 

Neuromuscular paralysis This side effect most often results after direct intraperitoneal or intrapleural application of large doses of aminoglycosides. The mechanism responsible is a decrease in both the release of acetylcholine from prejunctional nerve endings and the sensitivity of the postsynaptic site. Patients with myasthenia gravis are particularly at risk. Prompt administration of calcium gluconate or neostigmine can reverse the block. 

Q9 To which category of drugs does neostigmine belong Your answer should include its mechanism of action. 

Neostigmine has a mechanism of action quite similar to that of physostigmine. It effectively inhibits cholinesterase a about 10 M concentration. Its activity docs not vary with pH. and at all ranges it exhibits similar cationic properties (Fig. 17-IS). Skeletal muscle is also slimulatcd by nco-itigmine. a property that physostigtnine docs not have. 

Although a mechanism to rationally explain their findings is not presented. Green et al have reported data substantiating their previous observations on the influence of cholinesterase inhibitors on the oral absorption of sulfonamides. These workers found that the four-hour plasma levels of sulfacetamide, sulfonilamide and sulfaguanidine were enhanced when the rats were pre-treated with neostigmine as compared to those plasma levels found in the controls. 

A) Decreased blood pressure caused by hexamethonium Increased blood pressure caused by nicotine Increased skeletal muscle strength caused by neostigmine Tachycardia caused by exercise Tachycardia caused by infusion of acetylcholine Which of the following best describes the mechanism of action of scopolamine ... 

Because OP/CM in.secticidcs have been used extensively since parathion was developed, their mechanism of action has been the subject of intense investigations. Most of these mechanistic studies focused on ChE inhibition and metabo-li.sm in insects, mammals, and plants. Regarding the mechanism of functional changes, two groups of anti-ChEs other than insecticidal anti-ChEs were also studied extensively— that is, CMs such as physostigmine and neostigmine because... 

The involvement of a cholinergic component in the mechanism of action of morphine was proposed even before acetylcholine (ACh) had been shown positively to be present in the central nervous system. Slaughter and Munsell [70] demonstrated that the antinociceptive action of morphine in the cat was potentiated by concurrent administration of neostigmine, an inhibitor of the enzyme cholinesterase, a Rnding later confirmed in man [71,72]. Since then, a number of investigations have attempted to implicate ACh in morphine analgesia [73]. 

Absolute [1] neostigmine is contraindicated in patients with known hypersensitivity to neostigmine methylsulfate, intestinal or urinary tract obstruction, and mechanical peritonitis. 

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