Drugs affecting the autonomic nervous system ( Carbachol and Pilocarpine)
Carbachol
Structure:
The acetate is replace by ester of carbamate so, it is not hydrolysis by acetylcholinesterase
Activity:
It has nicotinic actions because choline is not methylated and it has lacks activity on muscarinic affinity.
Pharmacological action:
1- Carbachol can release epinephrine from the adrenal medulla via nicotinic action.
2- Carbachol stimulates pupil constriction in a process called miosis.
Uses:
1- systemic : Carbachol cannot be used systemically because it is high potency and non-selective.
2- local: glucoma and high intraocular pressure.
Side effect:
The carbachol does not have any side effects because it is used topically as an eye drop, as the side effects are due to the use of carbachol as a systemic and not a topical one.
Carbachol and pilocarpine are cholinergic agonists
Pilocarpine:
Structure:
Has tertiary amine so, it is not hydrolysis by acetylcholinesterase
Activity:
Has strong muscarinic activity , also it is uncharged and penetrate the central nervous system.
Pharmacological action:
1- systemically: stimulates the secretion of tears , sweat and saliva .
2- locally: Pilocarpine stimulates pupil constriction in a process called miosis.
Uses:
1- systemically: Xerostomia (dry mouth) and Sjögren’s syndrome ( lack of saliva and tears )
2- locally: glucoma and high intraocular pressure ( same as Carbachol )
Side effect:
1- Pilocarpine can penetrate the central nervous system which can in turn cause disturbances in the central nervous system.
2- Pilocarpine can cause an increase in the production of tears, sweat, and saliva.