The document discusses parasympathomimetic agents, including their mechanisms and therapeutic uses, such as treating atonic bladder and myasthenia gravis. It outlines various types of cholinergic drugs, including direct and indirect-acting agonists, and their side effects. Additionally, it describes the autoimmune nature of myasthenia gravis and its treatment options, including medication and surgical interventions.

1. PARASYMPATHOMIMETIC
AGENTS
Presented by Sonali Hiranwar
Mpharm 1st sem

2. CONTENTS
• INTRODUCTION
• CHOLINERGIC TRANSMISSION
• CHOLINERGIC RECEPTORS
• CLASSIFICATION OF DRUGS
• DISEASES

3. INTRODUCTION
• PARASYMPATHOMIMETICS OR CHOLINERGIC DRUGS ARE THOSE DRUGS
WHICH MIMIC THE ACTION OF STIMULATED PARASYMPATHETIC SYSTEM.
• ACTIONS OF PARASYMPATHOMIMETICS ARE
• EYES- MIOSIS [CONTRACTION OF PUPIL]
• LACRIMAL GLANDS- STIMULATE TEARS
• SALIVARY GLANDS-WATERY SECRETION
• HEART- DECREASE B.P.- DECREASE
• TRACHEA AND BRONCHI- CONTRACTION
• GIT-THE MUSCLE MOTILITY AND TONE
• BLOOD VESSEL- DILATION

10. DIRECT ACTING CHOLINERGIC AGONIST
.
• CHOLINERGIC AGONIST MIMIC THE EFFECT OF ACH BY BINDING
DIRECTLY TO CHOLINORECEPTORS
BETHANECHOL
IT IS STRUCTURALLY RELATED TO THE ACH IN WHICH ACETATE IS
REPLACED BY CARBAMATE AND CHOLINE IS METHYLATED. IT LACKS
NICOTINIC ACTIONS BUT DOES HAVE STRONG MUSCARINIC ACTIVITY.
ACTIONS- IT DIRECTLY STIMULATE MUSCARINIC RECEPTOR, CAUSING
INCREASED INTESTINAL MOTILITY AND TONE
TH. USE- IT IS USED TO STIMULATE ATONIC BLADDER; ALSO USED TO
TREAT NEUROGENIC ATONY AS WELL AS MEGACOLON

11. INDIRECT ACTING CHOLINRGIC AGONIST
• Reversible anticholinesterase
• ACETYLCHOLINESTERASE IS AN ENZYME THAT SPECIFICALLY CLEAVES
ACH TO ACETATE AND CHOLINE AND THUS TERMINATES ITS ACTIONS.
INHIBITION OF ACETYLCHOLINESTERASE INDIRECTLY PROVIDE A
CHOLINERGIC ACTIONS BY PROLONGING THE LIFETIME OF ACH. THIS
RESULTS ACCUMULATION OF ACH IN SYNAPTIC SPACE.
• EG- PHYSOSTIGMINE, NEOSTIGMIN

13. Phytostigmine
• PHYSOSTIGMINE IS AN NITROGENOUS CARBAMIC ACID ESTER FOUND
NATURALLY IN PLANTS. •
• ACTIONS- PHYSOSTIGMINE HAS A WIDE RANGE OF EFFECTS OVER
MUSCARINIC AND NICOTINIC SITES OF ANS. •
• IT CAN ENTER AND STIMULATE CHOLINERGIC SITES AT ANS. •
• TH. USE – INCREASE INTESTINAL AND BLADDER MOTILITY ; PLACED
TOPICALLY IN EYES, IT PRODUCE MIOSIS. IT IS USED TO TREAT GLAUCOMA.
IT IS ALSO USED IN THE TREATMENT OF OVERDOSE OF DRUGS WITH
ANTICHOLINERGIC ACTIONS LIKE ATROPINE ETC. •
• ADVERSE EFFECT – IF HIGH DOSES ARE USED, MAY LEAD TO CONVULSION,
BRADYCARDIC AND A FALL IN CARDIAC OUTPUT MAY ALSO OCCURS.
SOMETIME, PARALYSIS OF SKELETAL MUSCLES ALSO OCCURS.

14. Irreversible ANTICHOLINESTERASE
• A NUMBER OF SYNTHETIC ORGANOPHOSPHATE COMPOUNDS HAVE THE CAPACITY TO
BIND COVALENTLY TO ACETYLCHOLINESTERASE . THE RESULT IS A LONG LASTING
INCREASE IN ACH AT ALL SITES WHERE IT IS RELEASED. • EG- ECHOTHIOPHAT
• ECHOTHIOPHAT
• ECHOTHIOPHATE IS AN ORGANOPHOSPHATE COMPOUND HAVE THE CAPACITY TO BIND
VIA ITS PHOSPHATE GROUP TO –OH GROUP AT THE ACTIVE SITES OF
ACETYLCHOLINESTERASE. ONCE THIS OCCURS, ENZYME IS PERMANENTLY INACTIVATED
AND RESTORATION OF ACETYLCHOLINESTERASE ACTIVITY REQUIRES SYNTHESIS OF NEW
ENZYME MOLECULES. •
• ACTION- GENERALIZED CHOLINERGIC STIMULATION . •
• TH. USE- USED TO TREAT OPEN ANGLE GLAUCOMA ; POTENTIAL RISK OF CONTRACT
LIMITS USE OF GLAUCOMA. •
• ADVERSE EFFECT – PARALYSIS OF MOTOR FUNCTION [CAUSING BREATHING
DIFFICULTIES] AND CONVULSIONS; `

15. MYASTHENIA GRAVIS
• IT IS AN AUTOIMMUNE NEUROMUSCULAR DISORDER , IN WHICH WEAKNESS IS
CAUSED BY CIRCULATING ANTIBODIES.
• • ANTIBODIES BLOCK ACH RECEPTOR AT POST SYNAPTIC NEUROMUSCULAR
JUNCTION , INHIBITING THE STIMULATIVE EFFECT OF N.T. ACH.
• SIGNS AND SYMPTOMS
WEAKNESS IN ARMS, LEGS, NECK
• - CHANGE IN FACIAL EXPRESSION
• - DYSPHAGIA [ DIFFICULTY IN SWALLOWING ]
• - DOUBLE VISION
• - SHORTNESS OF BREATH
• - IMPAIRED SPEECH

16. CAUSES
• CAUSED BY DEFECT IN TRANSMISSION OF NERVE IMPULSE TO
MUSCLES , OCCURS WHEN NORMAL COMMUNICATION BETWEEN
NERVE AND MUSCLE IS INTRUPTED AT THE NEUROMUSCULAR
JUNCTION.
• IN MYASTHENIA GRAVIS , ANTIBODIES BLOCK ACH RECEPTOR AT POST
SYNAPTIC NEUROMUSCULAR JUNCTION , INHIBITING THE
STIMULATIVE EFFECT OF ACH.
• MYASTHENIA GRAVIS IS AN AUTO IMMUNE DISEASE BECAUSE THE
IMMUNE SYSTEM MISTAKENLY ATTACK ITSELF.

18. TREATMENT
• TREATMENT IS BY MEDICATION /SURGERY. –
• MEDICATION CONSISTS
• CHOLINESTERASE INHIBITOR TO MUSCLE FUNCTION
IMMUNOSUPPRESSANT DRUGS TO REDUCE AUTOIMMUNE PROCESS -
THYMECTOMY IS A SURGICAL METHOD TO TREAT MG.
• - FOR EMERGENCY TREATMENT, PLASMAPHERESIS OR IVIG CAN BE
USED AS TO REMOVE ANTIBODIES FROM THE BLOOD CIRCULATION