Pulmonary drug delivery system M.pharm -2nd sem P'ceutics
Lecture 9 .Parasympathetic agents.b pharmacy second year
1. • By Manjusha SK
• Associate professor
Medicinal chemistry l
Lecture 9
Para-Sympathomimetic agents
2. Para-Sympathomimetic agents
Introduction –
Parasympathomimetic agents are the compounds which mimic the actions of acetyl choline
and causes nerve stimulation.
The acetyl choline is the major neurotransmitter.
These agents are further divided into two types,
1.Direct acting para-sympathomimetics : These drugs bind to the nicotinic or
muscarinic receptors and causes excitation of cholinergic system.
2.Indirect acting para-sympathomimetics : These drugs inhibit the hydrolysis of
acetylcholine and hence increases the life of acetylcholine.
So it causes increased concentration of ACh at the receptor site to produce excitation of
cholinergic system.
These agents are also known as anticholinesterases.
4. SAR OF PARA-SYMPATHOMIMETIC AGENTS (drugs) – A.Direct acting agents -
Acetylcholine is the basic drug for this directly acting para-sympathomimetic category.
5. Some directly acting drugs are as follows
1) Acetylcholine -
Mechanism of Action : Acetylcholine is an direct acting quarter-ammonium cholinergic drug that has the
muscarinic effects.
Uses :- It is used as a miotic to reduce post-operative rises in intra-ocular pressure associated
with cataract surgery.
- It has a tonic action on smooth muscles.
- It is used as a vasodilator.
2) Carbachol –
Synthesis -
6. 2) Carbachol –
Synthesis –
Mechanism of Action : It is a quaternary ammonium parasympathomimetic agent having both
muscarinic and nicotinic actions.
Uses – used in management of glaucoma
used to produce miosis in ocular surgery.
3) Bethanechol –
Structure - Mechanism of Action : It is an choline
ester and show muscarinic activity.
It has little nicotinic activity.
Uses – used in the stimulation of GI tract.
It has prolong effect than acetylcholine.
7. 4) Methacholine -
Structure -
Mechanism of action – It is also an quaternary ammo.parasymapathomimetic with muscarinic actions.
It get hydrolysed by acetyl cholinesterase so it has more prolonged actions.
Uses – used in treament of reynaud's syndrome and glaucoma.
It is also used for peripheral vascular disease.
(In Raynaud's disease, smaller arteries that supply
blood to your skin become narrow, limiting
blood flow to affected areas (vasospasm))
8. 5) Pilocarpine -
Structure –
Mechanism of action –Pilcocarpine is a direct acting tertiary amine and it has muscarinic
effects of acetylcholine.
Uses –It is used mainly in the treatment of glaucoma and in treatment of dry eye or-dry mouth.
It is used in the treatment of open angle glaucoma.
It has also been used as a diaphoretic in diagnostic tests for cystic fibrosis and leprosy.
