Neostigmine-anticholinesterases(carbamates),skeletal muscle relaxant drug and its pharmacology

NEOSTIGMINE-

A cholinesterase inhibitor used in the treatment of myasthenia gravis and to reverse the effects of muscle relaxants such as gallamine and tubocurarine.

Neostigmine, unlike physostigmine, does not cross the blood-brain barrier. 

Pharmacology:

Indication-Neostigmine is used for the symptomatic treatment of myasthenia gravis by improving muscle tone.

Pharmacodynamic-Neostigmine is a cholinesterase inhibitor used in the treatment of myasthenia gravis and to reverse the effects of muscle relaxants such as gallamine and tubocurarine. Neostigmine, unlike physostigmine, does not cross the blood-brain barrier. By inhibiting acetylcholinesterase, more acetylcholine is available in the synapse, therefore, more of it can bind to the fewer receptors present in myasthenia gravis and can better trigger muscular contraction. 

Absorption-Neostigmine bromide is poorly absorbed from the gastrointestinal tract following oral administration

Protein binding-Protein binding to human serum albumin ranges from 15 to 25 percent.

Metabolism-Neostigmine undergoes hydrolysis by cholinesterase and is also metabolized by microsomal enzymes in the liver.

Half life- The half-life ranged from 42 to 60 minutes with a mean half-life of 52 minutes.

Drur Drug interactions:

Acetylcholine+Neostigmine=The risk or severity of adverse effects can be increased when Neostigmine is combined with Acetylcholine.

Fludrocortisone+Neostgmine=The risk or severity of adverse effects can be increased when Fludrocortisone is combined with Neostigmine.

Nadolol+Neostgmine= Neostigmine may increase the bradycardic activities of Nadolol.

Procyclidine+Neostgmine=The therapeutic efficacy of Procyclidine can be decreased when used in combination with Neostigmine.

Succinylcholine+Neostigmine=The serum concentration of Succinylcholine can be increased when it is combined with Neostigmine.

Therapeutic Uses:

>Treating myasthenia gravis. 

>Neostigmine is a cholinesterase inhibitor. It works by improving the transmission of nerve impulses in muscles so that the muscles are better able to work.

Side effects:

>Increased watering of mouthConstipation

>decreased sexual ability

>difficult urination

>dry mouth

>enlarged pupils

REFERENCE:-Tripathi K D"Essential of medical pharmacology",7th edition ,page no.105,107,108,109,350,354.