Clinical Pharmacy. An over view on Autacoids.......

1. Autacoids
Presented by:
Imran Ahammad Chowdhury

2. What I’ll present?
• Definition ,classification & functions of autacoids
• Histamine & Serotonin
LET’S START……….

3. Autacoids
• The word autacoids comes from the Greek "Autos" (self)
and "Acos" (relief, i.e. drug).
• Endogenous compounds;
• Play an important role in the physiological and
pathological processes;
• Have very short t1/2;
• Have local action.
So, they are biological factors which act like local hormones,
have a brief duration, and act near the site of synthesis.
• e. g. eicosanoids, angiotensin, neurotensin, NO (nitric
oxide), kinins, histamine, serotonin, endothelins,
palmitoylethanolamide, etc.

4. Functions of Autacoids
• They take part in:
1. Inflammation
2. Allergic reactions
3. Anaphylactic reactions( not so much)
4. Neurotransmission
5. Gastric acid secretion
6. Neuroendocrine regulation
• In the central nervous system, they are responsible for
1. Wakefulness
2. Decreased Appetite
3. Regulation of drinking
4. Regulation of temperature
5. Secretion of ADH
6. Control of blood pressure
7. Perception of pain.

5. Classification of Autacoids
• 1) Decarboxylated amino acids
a) Histamine
b) Serotonin
• 2) Polypeptide
a) Angiotensin
b) Plasmakinin
c) Vasopressin
d) Vasoactive Intestinal Polypeptide
e) Substance P
f) Slow reacting substance of anaphylaxis
• 3) Eicosanoid
a) Leukotrienes
b) Thromboxanes
c) Prostaglandins

6. HISTAMINE
&
SERETONIN

7. HISTAMINE
• is an organic nitrogenous compound involved in local
immune responses; acts as a neurotransmitter.
• Receptor Types: H1, H2,and H3
• Histamine mediates its effects by interacting with
receptors.

8. Pharmalogical effects of Histamine
1)Histamine promotes( intestinal and Bronchiolar )
smooth muscle contraction which is an H1 receptor
mediated effect
2)Histamine significant increase in gastric acid and gastric
pepsin secretion which is an H2 receptor mediated
effect
3) Vasodilation of arterioles and precapillary sphincters
which is an H1and H2 receptor mediated effect
4) Increase the gastric acid secretion
5) Mainly contract the smooth muscle, especially in
bronchus

9. Histamine antagonists

10. H1 receptor antagonists
Therapeutic uses:
1) Allergic Reactions: allergic rhinitis , Atopic dermatitis, hay fever,
urticaria
2) Motion sickness: vestibular disturbances
3) Sedation and hypnotics. : These agents to be used has sleep-
aids, i.e. hypnotics.
Adverse effects:
• 1) Inhibition of CNS
• 2) Some first-generation H1 antagonists have strong antimuscarinic
actions (atropine-like effects)
• 3) others: Second-generation over dosage: may induce cardiac
arrhythmias

11. H2 receptor antangonists
Clinical use:
• Peptic Ulcer and Duodenal Disease
• Gastric Ulcer: reduce symptoms promote healing for benign gastric ulcers
• Gastro esophageal Reflux Disorder (erosive esophagitis)
Hypersecretory Disease:
• Zollinger-Ellison syndrome:
• acid hypersecretion -- caused by gastrin-secreting tumor
• Systemic mastocytosis and multiple endocrine adenomas:
Adverse effect:
Generally well tolerated
• Most common adverse effects: diarrhea , dizziness , somnolence ,
headache , rash, thrombocytopenia , neutropenia , aplastic anemia)
• Cemitidine- CNS effects (uncommon): elderly: confusion states

12. SEROTONIN

13. Serotonin
• Serotonin or 5-hydroxytryptamine (5-HT) is a
monoamine neurotransmitter. Biochemically derived
from tryptophan
• Primarily found in
-Gastrointestinal tract (GI tract),
-blood platelets,
-and the CNS of animals, including humans.
• It is popularly thought to be a contributor to feelings of
well-being and happiness.

14. Antagonists
Clozapine:
•Reduce incidence of EPS
•High affinity for
dopamine receptors
•Reduced negative
symptoms of schizophrenia
Risperidone:
• D2 receptor blocker
• Reduced negative
symptoms of schizophrenia
• Low incidence of EPS
Methysergide:
• Used for diarrhea &
malabsorption in patients
with carcinoid tumors
• Cyproheptadine:
• H1 blocker, Weak
anticholinergic and mild CNS
depressant
• Used for skin allergies,
cold urticaria
• Counteract the sexual
side effects of SSRI’s