Histamine and serotonine

Autacoids definition

Substances having autocrine local effects

Autacoids effect type

Autocrine local effects

Basis of autacoid classification

Chemical structure

Types of autacoids based on structure

Peptide autacoids amine autacoids lipid autacoids

Example of peptide autacoid Angiotensin

Angiotensin is a peptide autacoid

Example of peptide autacoid Bradykinin

Bradykinin is a peptide autacoid

Example of amine autacoid Histamine

Histamine is an amine autacoid

Example of amine autacoid 5-HT

5-HT serotonin is an amine autacoid

Example of lipid autacoid Prostaglandins

Prostaglandins are lipid autacoids

Example of lipid autacoid Leukotrienes

Leukotrienes are lipid autacoids

Example of lipid autacoid Thromboxane

Thromboxane is a lipid autacoid

H1 receptor location

CNS and bronchus

H1 receptor action Allergy

Produces allergic response

H1 receptor action RAS

Stimulates reticular activating system

H1 receptor action wakefulness

Promotes wakefulness

H1 receptor blockers

First and second generation antihistamines

H2 receptor location

Stomach

H2 receptor action

Secretion of gastric acid

H2 receptor blocker Ranitidine

Ranitidine blocks H2 receptors

H2 receptor blocker Cimetidine

Cimetidine blocks H2 receptors

H3 receptor location

Presynaptic

H3 receptor action

Acts as presynaptic brake

H3 receptor drug type

H3 inverse agonist

H3 inverse agonist example

Tiprolisant Pitolisant

Clinical use of Pitolisant

Used in narcolepsy

H4 receptor location

WBC

H4 receptor action

Chemotaxis

First generation H1 blockers BBB

Cross blood brain barrier

Sedation with first generation antihistamines

Causes sedation

Anticholinergic action of first generation antihistamines

Present

Side effects of first generation antihistamines

Anticholinergic side effects occur

Uses of first generation antihistamines

Allergy and motion sickness

Property of first generation antihistamines

Prophylaxis of motion sickness

Anti-parkinsonism effect of first generation antihistamines

Useful in drug-induced parkinsonism

Anti dystonia effect of first generation antihistamines

Useful in acute muscular dystonia

Common cold treatment property of first generation antihistamines

Anticholinergic action

Diphenhydramine class

First generation antihistamine

Promethazine special feature

Maximum anticholinergic action

Dimenhydrinate class

First generation antihistamine

Pheniramine class

First generation antihistamine

Chlorpheniramine class

First generation antihistamine

Cyclizine class

First generation antihistamine

Cinnarizine class

First generation antihistamine

Second generation antihistamines BBB

Do not cross blood brain barrier

Sedation with second generation antihistamines

No sedation

Anticholinergic action of second generation antihistamines

Absent

Use of second generation antihistamines

Useful only for allergy

Astemizole status

Not used due to QT prolongation

Terfenadine status

Not used due to QT prolongation

Fexofenadine relation to Terfenadine

Active metabolite of terfenadine

Loratidine class

Second generation antihistamine

Des-loratidine class

Second generation antihistamine

Cetirizine class

Second generation antihistamine

Levocetirizine class

Second generation antihistamine

Azelastine route

Topical antihistamine

Olopatadine route

Topical antihistamine

Third generation antihistamines definition

Metabolite or isomer of second generation drugs

Example of third generation antihistamine Fexofenadine

Fexofenadine is a third generation antihistamine

Example of third generation antihistamine Desloratidine

Desloratidine is a third generation antihistamine

Example of third generation antihistamine Levocetirizine

Levocetirizine is a third generation antihistamine

CAT drugs meaning

Cisapride Astemizole Terfenadine

Reason for withdrawal of CAT drugs

QT prolongation

Metabolism of CAT drugs

CYP3A4 metabolism

CYP3A4 inhibitor Ciprofloxacin

Increases QT prolongation risk

CYP3A4 inhibitor Ketoconazole

Increases QT prolongation risk

CYP3A4 inhibitor Erythromycin

Increases QT prolongation risk

Effect of combining CAT drugs with enzyme inhibitors

QT prolongation

5-HT full form

Serotonin

5-HT1A receptor location

Presynaptic

5-HT1A receptor action

Presynaptic brake

5-HT1A receptor drug type

Agonist

5-HT1A agonist Buspirone

Used for anxiety

5-HT1B/1D receptor location

Blood vessels of brain

5-HT1B/1D receptor action

Vasoconstriction

5-HT1B/1D drug type

Agonist

Ergotamine use

Acute severe migraine

Sumatriptan class

Triptan used in migraine

Naratriptan class

Triptan used in migraine

Eletriptan class

Triptan used in migraine

Rizatriptan class

Triptan used in migraine

5-HT2A/2C receptor location

Brain

5-HT2A/2C drug type

Blockers

Clozapine use

Atypical antipsychotic

Olanzapine use

Atypical antipsychotic

5-HT2C receptor drug type

Agonist

Lorcaserin use

Obesity

5-HT3 receptor location

CTZ

5-HT3 receptor action

Emesis

5-HT3 drug type

Blockers

Ondansetron use

DOC for chemotherapy induced vomiting

Granisetron use

Used for vomiting due to chemotherapy

Tropisetron use

Used for radiotherapy induced vomiting

Dolasetron use

Used for post-operative vomiting

Palonosetron class

5-HT3 blocker

5-HT4 receptor location

GIT

5-HT4 receptor action

Prokinetic

5-HT4 drug type

Agonist

Cisapride use

GERD

Mosapride use

GERD

Prucalopride use

GERD