Physostigmine is a reversible cholinesterase inhibitor derived from natural sources, primarily used to treat conditions like glaucoma, myasthenia gravis, and severe anticholinergic toxicity. It increases acetylcholine levels, affecting both nicotinic and muscarinic receptors, and can cross the blood-brain barrier, making it useful for cognitive disorders like Alzheimer's. However, it carries serious side effects, including the risk of overdose leading to respiratory failure and cardiac arrest.

1. By:- “Rishabh Sharma”
Bsc. Clinical Research“Year-2nd
Semester-3rd
TOPIC:- PHYSOSTIGMINE

2. Physostigmine is a
highly toxic
parasympathomimetic
alkaloid, specifically, a
reversible cholinesterase
inhibitor.

3. It occurs naturally in
the Calabar bean
and the Manchineel
tree
However, before its
discovery by Sir
Robert Christison in
1846, it was more
prevalent as a poison.

4. A cholinesterase
inhibitor that is rapidly
absorbed through
membranes. It can be
applied topically to the
conjunctiva.

5. It can also cross the blood-
brain barrier and is used
when central nervous system
effects are desired, as in the
treatment of severe
anticholinergic toxicity.

10. For the treatment of
glaucoma, Myasthenia
Gravis and in the
treatment of severe
anticholinergic toxicity.

11. Recently, it has begun to be
used in the treatment
of orthostatic hypotension
.Another use of
physostigmine is to reverse
the effects of barbiturates

12. Physostigmine is a
parasympathomimetic,
specifically, a reversible
cholinesterase inhibitor which
effectively increases the
concentration of acetylcholine.

13. It is also used to reverse
neuromuscular blocking.
Physostigmine also has other
proposed uses: it could reverse
undesired side effects
of benzodiazepines

14. Its mechanism is to prevent the
hydrolysis of acetylcholine by
acetylcholinesterase at the
transmitted sites of
acetylcholine.

15. More recently, physostigmine
has been useful for the treatment
of cholinergic disorders and
myasthenia gravis. It is also used
improve the memory of
Alzheimer's patients due to its
potent anticholinesterase
activity.

16. Physostigmine is used to treat
glaucoma. It is also used to
treat the central nervous system
effects of atropine overdose and
other anticholinergic drug
overdoses..

17. “Physostigmine indirectly
stimulates both nicotinic
and muscarinic receptors.”

18. Physostigmine inhibits
acetylcholinesterase, the enzyme
responsible for the breakdown of used
acetylcholine. By interfering with the
metabolism of acetylcholine,

19. Duration of Action: 30-60 min
Mechanism of Action-
Indirect acting
parasympathomimetic

20. 1) increased sweating
2) loss of bladder control,
3) muscle weakness,
4) nausea, vomiting, diarrhoea,
stomach cramps
5) shortness of breath, tightness
in chest, or wheezing,.

21. 6)slow or irregular heartbeat,
7)unusual tiredness or
weakness,
8)watering of mouth,
9)blurred vision or and eye pain.

22. Side effects may include
1) Nausea,
2) Vomiting,
3) Diarrhea,
4) anorexia, 5)dizziness,
headache, stomach pain,
sweating, dyspepsia, and
seizures.

23. Death can occur rapidly
following overdose as a
result of respiratory
arrest and paralysis of the
heart.

24. It causes a contraction of the
pupil and stimulates the
fibers of the ciliary muscle. It
is useful in
treating “mydriasis”.

25. “ESSENTIALS OF MEDICAL
PHARMACOLOGY:- KD TRIPATHI”
https://reference.medscape.com/drug/physostigm
ine-343743#10
https://en.wikipedia.org/wiki/Physostigmine