Autacoids Flashcards
What are the 4 autacoids
Histamine
Serotonin
Prostaglandins
Peptides
What drugs inhibit histamine release
Cromolyn sodium
Catecholamines
Phosphodiesterase inhibitors
Glucocorticoids
Major H1 Mediated Effects on Vessels and Smooth Muscle
Contraction of smooth muscles of: GI, bronchioles, uterus, Large blood vessels
Vasodilation followed by contraction leading to increased permeability, edema, hypotension and hypovolemic shock
Other H1 Mediated Effects
Stimulation of exocrine secretion
Positive inotropic effect
CNS stimulation, inhibition of appetite
Major H2 Mediated Effects
Gastric acid secretion
Positive inotropic effect and increased heart rate
H1 antagonists are __
Antihistamines
H1 Antagonists - First Generation Characteristics
Crosses BBB
Sedating
H1 Antagonists First Generation Drugs
Diphenydramine Promethazine Cyproheptadine Terfenadine Meclizine
H1 Antagonists Second Generation Characteristics
Non-sedating
Does not cross BBB
More receptor selectivity
What do some second generation antagonists exhibit
non-competitive antagonism
anti-inflammatory effects by stabilizing mast cells
Second generation drugs
Piperidines (Terfenadine, astemizole, loratadine)
Ketotifen (noncompetitive H1 agntagonist)
Do first or second generation drugs have a longer duration of action
Second generation (12-24 hrs)
**First generation is 3-12 hrs
H1 Antagonists are readily absorbed ___
Orally
H1 Antagonists are metabolized by ___ and excreted by ___
Metabolized by the liver and excreted in the urine
Which H1 drug is used as an antiemetic, antitussive and sedative
Diphenhydramine
Which H1 drug is available as opthalmic for treatment of allergic conjunctivitis and orally as adjunctive for asthma prevention
Ketotifen
Side effects of H1 Antagonists
Anticholinergic effect
GI irritation
Alpha adrenergic block (phenothiazines)
Which two H1 Antagonists are associated with Cardiac Arrhythmias
Terfenadine and Astemizole
What are the H2 Antagonist drugs
Cimetidine
Ranitidine
Famotidine
Nizatidine
Do H2 Antagonists cross the BBB
NO
Cimetidine effects
Immunomodulatory
Inhibits suppressor T cells
Enhances cell mediated immunity
Ranitidine and Nizatidine effects
Cholinergic activity by inhibiting acetyl cholinesterase –> stimulates GI motility
Uses for H2 Antagonists
Peptic Ulcer
Gastric erosive disease
Gastroesophageal reflux disease
Duodenal ulcer
Cimetidine is used in the treatment of equine ____
Melanoma
Ranitidine or Nizatidine can be used as a ___
Prokinetic
Cisapride Mechanism of Action
5-HT4 receptor agonist in enteric neurons
Cisapride is a ___ and acts on ___
Prokinetic
Small and Large intestine
Fluoxetine Mechanism of Action
Selective Serotonin reuptake inhibitor - antidepressant
Increases serotonin levels in the brain
Fluoxetine Clinical Uses
Canine separation anxiety
Behavioral disorders in dogs and cats
Inappropriate elimination in cats
Side effects of Fluoxetine
Nausea
Anorexia
Irritability
Sleeping disturbances
Cyproheptadine Mechanism of Action
Blocks H1 Receptors, serotonin receptors
Inhibition of serotonin inhibits ACTH
Uses for cyproheptadine
Antihistamine
Appetite stimulant in small animals
Serotonin Syndrome in dogs and cats
Ondansetron Mechanism of Action
5-HT3 Receptor Antagonist (central and peripheral)
Use for Ondansetron
Prevention and treatment of anticancer chemotherapy induced nausea and vomiting
Metoclopramide Mechanism of Action
5-HT3 Receptor Antagonist
D1 and D2 receptor antagonist
Uses of Metoclopramide
Antiemetic
Prokinetic
Mirtazapine Mechanism of Action
Enhances noradrenergic and serotonergic activity by antagonizing central presynaptic alpha2 adrenergic inhibitory autoreceptors and heteroceptors
Potent antagonist of 5-HT2 and 5-HT3 receptors
Mirtazapine uses
Antidepressant
Antiemetic
Serotonin Antagonists
Cyproheptadine
Ondansetron
Metoclopramide
Mirtazapine
Neurokinin Antagonist
Maropitant Citrate
Maropitant Citrate Mechanism of Action
Blocks Neurokinin 1 receptors preventing substance P from binding –> antiemetic (pain, stress, anxiety, psychologic stress/vomiting)
Maropitant Citrate Uses
Only used in dogs over 16 wks
Tablet or injection for prevention of acute vomiting due to motion sickness
Where is renin secreted from and what does it do
Juxtaglomerular apparatus
Converts angiotensinogen to angiotensin 1
What stimulates the release of renin
Hypotension, decreased renal blood flow, low Na or Cl, sympathetic stimulation (B1 adrenergic)
What inhibits renin secretion
Angiotensin 2, ADH, Hypertension, Increased Na reabsorption, B1 Adrenergic blockers
What does Angiotensin 2 do
Potent Vasocontrictor, Stimulates aldosterone secretion, inhibits renin
Angiotensin 2 Antagonists
ACE Inhibitors
Angiotensin 2 Receptor Antagonists - Losartan
Prostaglandins
Misoprostol
Fluprostenol
Bimatoprost
Misoprostol Mechanism of Action
Causes GI cytoprotection and decreases acid secretion
Misoprostol use
Given orally as an anti ulcer drug
Fluprostenol Mechanism of Action
Causes luteolysis
Stimulates motility of the smooth muscles of repro. tract
Fluprostenol use
Reproduction
Bimatoprost Mechanism of Action
PG agonist - increases uveoscleral outflow by stimulating FP receptors in the eye
Bimatoprost use
Topically on eye in treatment of open-angle glaucoma or ocular hypertension
Prostaglandin Inhibitors
Cyclooxygenase Inhibitors - NSAIDS
Phospholipase A2 Inhibitors - Corticosteroids
Leukotrienes Inhibitors
Zafirlukast, Zileuton
Zafirlukast Mechanism of Action
Leukotriene receptor antagonists
Zafirlukast use
Prevention of bronchoconstriction in bronchial asthma in cats
Zileuton Mechanism of Action
5-Lipoxygenase inhibitor (leukotriene formation inhibition)
Zileuton use
Prevention of bronchoconstriction in bronchial asthma
What is Oclacitinib
Janus Kinase Inhibitor
Oclacitinib Mechanism of Action
Inhibits pruritogenic and pro-inflammatory cytokines by inhibiting JAK1 and JAK3 without inhibiting cytokines involved with hematopoiesis (JAK2)
Oclacitinib use
Control of pruritis associated with allergic dermatitis and atopic dermatitis (dogs over 12 months)
