ADINA INSTITTUE OF PHARMACEUTICAL SCIENCES SAGAR BY IMRAN KHAN

1. ADINA INSTITUTE OF PHARMACEUTICAL SCIENCES SAGAR
INDIA
ASSO.PROF.IMRAN KHAN
imrankhanaips@gmail.com

2. used to treat symptoms of allergies. These drugs help treat conditions
caused by too much histamine, a chemical created by your body’s immune
system. Antihistamines are most commonly used by people who have
allergic reactions to pollen and other allergens. They are also used to treat
a variety of other conditions such as stomach problems, colds, anxiety and
more.

3. H1-ANTIHISTAMINES –
1. Diphenhydramine (ALKYLAMINE)
(ETHNOLAMINE)
2. DIPHENHYDRAMINE HYDROCHLORIDE
4 . PIPERAZINE
3.PHENOTHIAZINE(PROMEYHAZINE)

4.  1. CIMETIDINE
 2.RANTIDINE-
 3.FAMOTIDINE -

9. MOA- Diphenhydramine is a first-generation histamine H1 receptor
antagonist (H1 antihistamine) that is widely available as a non-
prescription, over-the-counter (OTC) medication. As an OTC
medication, diphenhydramine is typically formulated as tablets and
creams indicated for use in treating sneezing, runny nose, itchy/watery
eyes, itching of nose or throat, insomnia, pruritis, urticaria, insect
bites/stings, allergic rashes, and nausea

10. 
MOA Dimenhydrinate is a theocrats salt that separates into diphenhydramine
and 8-chlorotheophylline. While the exact mechanism of action is unknown,
diphenhydramine is theorized to reduce disturbances to equilibrium through ant
muscarinic effects or histamine H1 antagonism
USES Diphenhydramine is an antihistamine used to relieve symptoms of
allergy, hay fever, and the common cold.

11. Doxylamine is a first-generation antihistamine used as a short-
term sedative and hypnotic (sleep aid) or in combination
formulations to provide night-time allergy and cold relief. It
provides a calmative effect in preparations containing the
analgesics paracetamol (acetaminophen) and codeine. It is
prescribed in combination with vitamin B6(pyridoxine) to
prevent morning sickness in pregnant women.

12. Clemastine:
Clemastine is used to relieve hay fever and allergy symptoms,
including sneezing; runny nose; and red, itchy, tearing eyes.
Prescription strength clementine is also used to relieve the
itching and swelling of hives.
Antihistamines competitively bind to histamine receptor
sites, thus reducing the neurotransmitter's effects. Effects of
histamine (which are countered by antihistamines) include:

13. Promethazine is a an antagonist of histamine H1, post-synaptic
mesolimbic dopamine, alpha adrenergic, muscarinic, and NMDA
receptors. The antihistamine action is used to treat allergic
reactions.7 Antagonism of muscarinic and NMDA receptors
contribute to its use as a sleep aid, as well as for anxiety and tension
Antagonism of histamine H1, muscarinic, and dopamine receptors
in the medullary vomiting center make promethazine useful in the
treatment of nausea and vomiting

14. 
is an antihistamine used to treat motion sickness and the
feeling like the world is spinning (vertigo) Common side
effects include sleepiness and dry mouth.

15. 
The mechanism of action of cimetidine as an antacid is as
a histamine H2 receptor antagonist. It has been found to bind to the
H2 receptor with a Kd of 42 nM. Cimetidine is reported to be
a competitive and reversible inhibitor of several CYP450 enzymes,
Cimetidine is used to inhibit stomach acid production and is used in
the treatment of heartburn and peptic ulcers. Reported side
effectsof cimetidine
include diarrhea, rashes, dizziness, fatigue, constipation,
and muscle pain, all of which are usually mild and transient

16. 
After a meal, the hormone gastrin, produced by cells in the
lining of the stomach, stimulates the release of histamine,
which then binds to histamineH2 receptors, leading to the
secretion of gastric acid. Ranitidine reduces the secretion of
gastric acid by reversible binding to histamine (H2)
receptors,

17. 
Activation of H2 receptors located on parietal cells
stimulates the proton pump to secrete acid. Famotidine
(H2 antagonist) blocks the action of histamine in the parietal
cells, ultimately blocking acid secretion in the stomach.
Relief of heartburn, acid indigestion, and sour stomach
Treatment for gastric and duodenal ulcers
Treatment for pathologic gastrointestinal hypersecretory
conditions such as Zollinger–Ellison syndrome and multiple
endocrine adenomas
Treatment for gastroesophagea reflux disease (GERD)
Treatment for esophagitis

18. ADINA INSTITUTE OF PHARMACEUTICAL SCIENCES
SAGAR MP INDIA
BY –ASSO.PROF. IMRAN KHAN