Autoacoids And Autacoid Antagonists Flashcards by Gopu Premrajan

Pupillary sphincter is interacted by _______________

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Radial muscle of the eye is innervated by

Autonomic system (PNS/CNS)

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What compounds are autacoids?

histamine
serotonin
eicosanoids

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All histamine receptors are _________ protein linked and have ___________ activity

G protein; constitutive activity (the receptors still have some activity even in the absence of agonists)

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Where can Histamine 1 (H1) receptors be found?

What kind of G protein does it have?

endothelium
smooth muscle cells
nerve endings

-Gq protein (PLC)

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Where can H2 receptors be found and what type of G protein are the coupled with?

gastric mucosa
cardiac muscle cells
some immune cells

-Gs (adenylyl cyclase)

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Which H receptor is found in the gastric mucosa?

MUCOSA not smooth muscle

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H2 receptors cause vasodilation by _______________ while H1 receptors cause vasodilation by ______

Acting on vascular smooth muscle and uses cAMP;

Acting on endothelial cells and cause production of NO

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What is the effect of H2 receptors on the heart

↑ contractility and ↑ pacemaker rate

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Which histamine receptors are found on the heart?

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Histamine induced edema results form the action of histamine on ________ receptors in blood vessels

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What is the effect on ____ (histamine) receptor on bronchial and GI smooth muscle?

H1; CONTRACTION

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What is the effect of the activation of H2 receptors on gastric parietal cells?

Powerful stimulant of gastric acid secretion

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What are the three classes of drugs that are histamine antagonists

physiological antagonists
release inhibitors
receptor antagonists

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__________ in a physiological antagonist to histamine

Epinephrine

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___________ and ________ are release inhibitors which are histamine antagonists

Cromolyn; nedocromil

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Is the MOA of cromolyn and nedocromil and what kind of drugs are they?

They are release inhibitors that act as histamine antagonists

Reduce immunologic mast cell degranulation

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_______ agonists appear to be bale to ↓ histamine release

β2

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What are two types of H1 receptor antagonists and what is a key difference?

1st generation: sedative effects and anti muscarinic effects

2nd generation: less sedating effect because they have P glycoproteins and less liposoluble

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________ generation of H1 receptor antagonists have less sedative effects because of: (2)

2nd generation

less liposoluble
P glycoproteins

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Examples of first generation H1 receptor antagonist (7)

chlorpheniramine
cyclizine
diphenhydramine
dimenhydrinate
hydroxyzine
meclizine
promethazine

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What 3 drugs are 2nd generation H1 receptor antagonists

fexofenadine
loratadine
cetirizine

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H1 blockers are now know to be _______________ because the H1 receptors have constitutive activity

Inverse agonists

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H1 receptor antagonists are useful for treating __________ but NOT for __________

Allergic conditions;

NOT useful in treating bronchial asthma because histamine is not the only mediator in that condition

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Which class of drugs is useful for treating motion sickness and nausea? MOA?

- 1st generation H1 receptor antagonists - block central H1 and M1 (emesis) receptors - second generation is not as full because cant enter CNS as well and dont have the ability to block M1 receptor

What kind of drug is diphenhydramine and what can it be used for?

- 1st generation H1 receptor antagonist | - treat insomnia, allergic reactions

What four drugs are H2 receptor antagonists?

- cimetidine - ranitidine - famotidine - nizatidine -tidine

What is the main clinical use of cimetidine and other similar drugs?

Inhibits gastric acid secretion (competitively blocks H2 receptors on parietal cells)

Clinical uses for H2 receptor antagonists:

- peptic ulcers - acute stress ulcers - GERD

H2 receptor antagonists are very safe drugs except for _________ especially in patients with ________

Cimetidine; | Elderly patients or those who have renal or hepatic dysfunction

What are some adverse effects of cimetidine?

- Confusion, hallucinations, and agitation when given IV to elderly patients or those with renal/hepatic dysfunction - inhibits P450 - had antiadrogenic effects: gynecomastia, ↓ sperm count and galactorrhea in women

All of sertonin receptors are G protein coupled except _________ which is __________

5 HT3; ligand gated ion channel

______ is the only monoamine NT receptor that functions as a ligand gated ion channel

5-HT3 receptor

What are the two serotonin receptor agonists class of drugs?

5HT 1D/1B | 5 HT4

What is the suffix for 5HT 1D/1B receptor agonists?

- -triptan

5 HT 1D/1B receptor agonists are contraindicated in ________

Patients with coronary artery disease or angina because they can cause coronary vasospasm

Triptans are the first line therapy for ________________

TREATMENT of acute severe migraine attacks

What drug is useful in the prophylaxis for migraines?

Propranolol (β blocker)

What is the MOA of 5- HT1D/1B receptor agonists in treating migraines?

1. Can bind to the 5-HT 1D receptor on the nerve terminal which then inhibits the release of CGRP form the nerve terminal and thus preventing vasodilation 2. Can bind to the 5 HT 1B receptor on the blood vessel which causes vasoconstriction

Vasodilation/vasoconstriction is what causes migraines

Vasodilation

Where is 5HT 1D receptor located and what is the effect when triptans bind to it?

On the nerve terminal; | Prevents the release of CGRP and thus prevents vasodilation

___________ and ________ are 5HT4 receptor agonists

Metoclopramide; cisapride Both are prokinetic agents

Metoclopramide is a _________ agonist and is a prokinetic agent. How? (2 ways)

5 HT4 receptor; Prokinetic effect: facilitates gut motility 1. Facilitates release of Ach from enteric neurons → contractions 2. Counteracts the inhibitory effects dopamine has on cholinergic neurons

What are some adverse effects of metoclopramide?

- somnolence (drowsiness), nervousness and dystonic reactions - extrapyrmaidal effects and tardive dyskinesia (rare) because it blocks the dopamine effects

________ is no longer given as a prokinetic agent due to cardiac adverse effects due to _________

Cisapride; prolonged QT interval

Classes of drugs that are sertonin antagonists

- 5 HT2 receptor antagonists - 5 HT3 receptor antagonists - ergot alkaloids

Cyproheptadine is a _________________ that is used for _______________

5 HT2 receptor antagonist; | Allergic rhinitis, vasomotor rhinitis, and management of serotonin syndrome

Which drug also also potent H1 blocking actions?

Cyproheptadine (5 HT2 receptor antagonist) This is why it can be used to treat allergic rhinitis

__________ is a 5 HT3 receptor antagonist that is used for _________

Ondansetron; Anti emetic that is used for severe nausea and vomiting that occurs with chemotherapy

Ergot alkaloids are useful for treating migraine pain; specifically _________ and _________

(triptans are preferred) Ergotamine and dhihydroergotamine

What class and specific drugs would be used to treat hyperprolactinemia caused by a pituitary tumor?

Ergot alkaloids; | Bromocriptine and cabergoline

If oxytocin is ineffective in controlling postpartum hemorrhage, give ______ or ________

Ergonovine or methylergonovine IM Ergot alkaloids

Ergonovine given via IM can be used to treat ____________ but if given via IV, can be used for __________

Postpartum hemorrhage (if oxytocin is ineffective) Diagnosis of variant angina because it causes coronary spasm in patients with it

_____________ of variant angina can be done via what ergot alkaloid?

Diagnosis; | Ergonovine given via IV

What are some clinical uses that ergot alkaloids are used for?

- treatment of migraines (ergotamine and dihydroergotamine) - hyperprolactinemia (bromocriptine and cabergoline) - post partum hemorrhage ( ergonovine or methylergonovine) - diagnosis of variant angina (ergonovine)

What are adverse effects of ergot alkaloids and when is it contraindicated?

- vasospasm Contraindicated in: - pregnant women - patients with peripheral vascular disease, coronary artery disease, HTN, and impaired hepatic/renal function - don’t give with drugs that cause vasoconstriction

What are the main subgroups of eicosanoids and what is the main course of eicosanoids ?

Subgroups: - prostaglandins - prostacyclins - thromboxanes - leukotrienes Arachadonic acid is the main source

COX 1 is found in ___________ as a ________ and is involved in _______

Most cells; constitutive enzyme; normal homeostasis

COX 2 is found in __________

Inflammatory cells; induced by inflammatory stimuli

____________ and _______ are leukotrienes that are potent _________ and secreted in asthma and anaphylaxis

LTC4 and LTD4; | Bronchoconstrictors

The contractile effects of eicosanoids on smooth muscle are mediated by ______ while the relaxing effects are mediated by _______

Calcium; cAMP

____________ is an eicasanoid analog (_____ analog) that is used to prevent peptic ulcers in patients taking high doses of NSAIDS

Misoprostol; PGE1 analog Reasoning: NSAIDs block COX1 and thus prevent the formation of prostaglandins which are protective in the gastric mucosa and prevent erosion.

Which eicasanoid drug is a PGE2 analog?

Dinoprostone Ripens cervix near term and is an abortifacient

____________ is a ______ analog that is used to maintain patency of the ductus arteriosus and is also used for _______

Alprostadil; PGE1 analog Also used for impotence

Epoprostenol, a _____ analog is used for (2)

- severe pulmonary hypertension - prevent platelet aggregation in dialysis machines Analog of a prostacyclin

What is the use of latanoprost?

It is a PGF2α derivative used for glaucoma

What are the three classes of drugs that are eicosanoid antagonists?

- leukotrienes pathway inhibitors: 5-lypoxygenase inhibitors and LTD4 receptor antagonists - glucocorticoids - NSAIDs

Zileuton inhibits ______

5-lypoxygenase (enzyme)

What are the two antagonists against LTD4 RECEPTORS

- zafirlukast and montelukast

Glucocorticoids inhibits __________ and also inhibits the synthesis of _________

- PLA2 → no release of arachadonic acid | - synthesis of COX 2