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Pharm + Thera > Anti-histamines and Gastrointestinal Drugs > Flashcards

Anti-histamines and Gastrointestinal Drugs Flashcards

1
Q

Where are histamine secreting cells found

A

most tissues; highest levels in respitory and GI tract.

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2
Q

Mast cells + what it treats

A

Mediates type 1 anaphylactic, immediate hypersensitivity allergic reactions involving IgE

treats things like: hay fever, red, hot swollen and itchy skin, hives, bronchospasm; or generalized causing anaphylactic shock

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3
Q

What is histamines role in the GI tract

A

To regulate gastic acid secretion, released by ECL cells.

-H2 receptors on acid-secreting cells

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4
Q

Role of Histamine in peripheral nervous system

A

-predominantly H1 receptors
-Itch + pain
-stimulation of somatic sensory cortex

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5
Q

Histamine in the CNS

A

-can act as a neurotransmitter or modulator

its effect: promotes wakefulness through H1 receptors

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6
Q

What histamine receptors are there

A

H1 + H2

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7
Q

What is its subtype and what do H1 receptors do

A

Gg: activation od phospholipase C, Calcium mobilization
-brain (excitatory)

-Blood vessels (endothelial cells- release NO, cause dilation of arterial smooth muscle)

-Other smooth muscle contraction

-heart= Increased blood flow

ANTAGONIST: used as treatment for allergic response, vertigo, insomnia

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8
Q

Cardiovasual role H1

A

Vasodilation of blood receptors
increases vascular permeability
-constricts smooth muscle
-increase heart rate

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9
Q

What is its subtype and what do H2 receptors do

A

Gs: activation of adenylyl cyclase

Brain (unknown)

-Blood vessels (minor dilation through smooth muscle)

-GI tract (minor increase in rate)

-Heart (minor increase in rate)

ANTAGONIST: used to reduce acid secretion by stomach exocrine glands

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10
Q

What is epinephrine and what does it do

A

It is a: physiological antagonist

-increases cAMP levels which inhibits Mast cell degranulation

-opposes actions of histamine in smooth muscle: Beta-adrenergic recepts induce bronchial dilation, caso constriction.

-Treatment for anaphylaxis
prevents/reverses cardiac collapse:increases Bp and heart contractility

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11
Q

What are the first generation of H1 receptor antagonists

A

Diphenydramine (benadryl) = most potent oal antihisamine

Dimenhydrinate (Dramamine): less drowsy, allergy/cold medications, reduces mucus secretions

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12
Q

what do the first generation of H1 receptor antagonists help with

A

-allergic rhinitis
-hay fever
-itching
-contract dermatitis
-insect bites
-conjunctivitis
-nausea +motion sickness
-NOT indicated for asthma

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13
Q

side effects from 1st generation of H1 antagonists

A

Antihistamine effects: sedation/sleep induction (from blocking H1)

Antimuscarinic effects-through nonspecific actions on muscarinic receptors
-Sedation (CNS effect): prominent.. tolerance is problem
-Drying of secretioins, urinary retention
-anti-parkinsons through muscarinic antagonism (CNS effect)

Other side effects:
-Topical local anesthetic (block NA+ channel)
-Anti-emetic (some anti-serotonin effects)

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14
Q

Drug interactions of First gen H1 antagonists

A

Other sedatives, anticholinergics, tricyclic antidepressants

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15
Q

What are the second generation H1 antagonist and how are they different + what do they do

A

Loratidine (Claritin) and Fexofenidine (allegra)

-Do not cross BBB
Side effects: not sedating, no anti-muscarinic effects

Clinical uses: non-drowsy allergy relief, not effective in motion sickness

Both have good oral bioavailability

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16
Q

What is the parietal cell responsible for

A

gastric acid secretion. Stimulated by Acetylcholine (M3 receptors) and H2 receptors

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17
Q

Where are parietal cells located

A

Corpus (body) of the stomach.
-parietal cells
-secrete acid

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18
Q

What do ECL, D, and G cells do (in gastric glands)

A

ECL: histamine releasing- STIMULATES acid secretion

D cells: somatostatin releasing; INHIBITS acid secretion

G cells: Gastrin releasing- STIMULATES acid secretion by parietal cells

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19
Q

what are some causes of peptic ulcer disease in order from most to least common

A

-H. pylori infection
-NSAIDS, aspirin
-stress ulcerations
-Zollinger-Ellison syndrome

20
Q

What is Helicobacter pylori, who found it, and what is its epidemiology, what does it need to survive, and what are its disease mechanisms

A

a basteria; eradication prevents ulcer recurrence. Discovered by Barry Marshall

-Rought of transmission unclear

-primarily childhood acquired (inversely with SES)

-survives in narrow pH range (needs acidic environment)

-Increased gastric acid secretion

-increased pepsinogen secretion

-decreased mucin secretion

21
Q

How to get rid of H pylori

A

-antibiotics
-reduce acid
(proton pump inhibitor, Omeprazole)
(H2 receptor antagonist, Cimetidine)

22
Q

Omeprazole; dynamics + cokinetics

A

-proton pump inhibitor (PPI)

-irreversible inhibitor (covalently modifies a chain)

Adverse effects: headache, diarrhea occur infrequently

Pro-drug: requires CYP450 to become active and thus inhibits CYP metabolism of other substrates.. drug interactions

23
Q

what does phase 1 drug metabolism do

A

-cytochrome p450 enzymes
-oxidize drugs
-different subtypes
-70% of all drug metabolism

24
Q

What is the warning on Omeprazole

A

Do NOT take with Plavix (clopidogrel)

why: Omeprazole occupies the cytochrome p450 enzyme needed to activate clopidogrel

Result: Increased risk of heart attack

25
Q

Cimetidine Dynamics and cokinetics

A

-Competitive H2 receptor antagonist
-selectively inhibits H2 receptors

Metabolized by: CYP450 (CYP inhibitor: can deplay metabolism of other CYP substrates)

Excreted by: kidney (reduce does in kidney failure)

26
Q

Ranitidine

A

Recall 2020
-competitive H2 receptor antagonist
-selectively inhibits H2 receptors
-top choice: same mechanism as cimetidine, less CYP inhibition

27
Q

What do NSAIDS do to elicit mucosal injury

A

Block COX-1

28
Q

Misoprostol Pharmadynamics

A

-synthetic PGE (agonist for PGE receptor Ep3/4)
-Protects gastric mucosa
-stimulates bicarbonate and mucus secretion
-reduces acid secretion
-only used for prevention of NSAID- induced ulcers

29
Q

Misoprostol pharmacokinetics and adverse effects

A

orally active
-rapidly absorbed and metabolized

-short half life

Adverse effects: can cause diarrhea, cramping, uterine contracting. CANNOT use with pregnant women, controversial for labor induction and for abortion

30
Q

What are the inputs and outputs for nausea in the medulla

A

inputs: CNS, visceral afferents, metabolic

Outputs: ONLY TWO vomiting center, chemoreceptor trigger zone

31
Q

Drugs/toxins associated with nausea/vomiting

A

-chemotherapeutic agents
-dopaminergic agents
-ethanol

32
Q

Treatment for severe nausea/vomiting

A

Serotonin subtype 5-HT3; Ondansetron (Zofran) is a 5-HT3 receptor antagonist

33
Q

What is Ondansetron uses

A

prophylaxis of chemotherapy and radiation-induced nausea and vomiting
- post-operative nausea and vomiting

34
Q

Side effects of ondansetron 5-HT3 inhibitor

A

GI effects
-diarrhea
-constipation

CNS effects
-headache
-fever
-lightheadedness
-dizziness, drowsiness
-blurred vision

Rash

Muscle spasm

35
Q

Cannabinoid CB1 receptor and 5-HT3 receptor

A

CB1 opposes 5-HT3

-THC is effective as anti-neasea agent following chemotherapy

36
Q

treatment for motion sickness (vertigo)

A

antagonists of H1 and mACh

Anticholinerics: Scopolamine: m1 AChR antagonist applied as a patch for prevention. Side effects for antichlinergic= urinary retention, constipation, vision disturbances

antihistamines: specific for H1 receptor + must cross BB
-dimenhydrinate, meclizine= long lasting. Promethazine= more sedation
side effects: drowsiness, anticholinergic effects

BEST AS PREVENTATIVES

37
Q

Drugs for neasea and vomiting

A

ondansetron, THC (dronabinol), dimenhydrinate

38
Q

Diphenhydramine’s Major indication, mechanism, adverse effects, and PK +notes

A

MI: allergy, motion, sickness, sedation

Mechanism: H1 receptor antagonist

Adverse effects: Tolerance to sedating effect prevents usefulness as insomnia treatment

Pk notes: t 1/2 9hrs; interactions with other sedating drugs and anticholinergic

39
Q

Dimenhydramine Major indication, mechanism, adverse effects, and PK +notes

A

Mi: motion sickness (vertigo) prevention

Mechanism: H1 receptor antagonist

Adverse effects: less sedating than dephenhydramine

Pk notes: t1/2 9 hours; prominent dry mouth anti-cholinergic

40
Q

Loratidine
Major indication, mechanism, adverse effects, and PK +notes

A

MI: allergy

Mechanism: H1 receptor agonist

Adverse effects: no sedation, not effective for motion sickness

Pk+notes: doesn’t cross BBB;short and long acting forms

41
Q

Cimetidine

Major indication, mechanism, adverse effects, and PK +notes

A

MI: peptic ulcer, GERD

Mechanism: H2 receptor antagonist

Adverse Effects: headache, diarrhea

Pk notes: CYP metabolism can inhibit metabolism of other drugs; and reduce dose kidney failure

42
Q

Epinephrine

Major indication, mechanism, adverse effects, and PK +notes

A

MI: anaphylaxis

Mechanism: BAR agonist, physiological antagonist of histamine

Adverse effects: tachycardia, hypertension

PK+ notes: emergency treatment IM injection

43
Q

Misoprostol

Major indication, mechanism, adverse effects, and PK +notes

A

MI: GI protechtant- prevention of gastric ulcers

Mechanism: PGE receptor agonist

Adverse effects: Diarrhea, abdominal pain

PK+notes: Short half-life; contraindicated in pregnancy

44
Q

Ondansetron

Major indication, mechanism, adverse effects, and PK +notes

A

MI: Nausea/vomiting

Mechanism: 5-HT3 receptor antagonist

Adverse effects: GI effects, CNS effects, rash

PK+notes: Effective for preventative of chemotherapy-induced or postoperative neasea

45
Q

endocrine disrupting chemicals with their impacts on health

A

-little evidence to prove exposures cause health impacts but…

-declines in male/female fertility
-abnormalities in M/F reproductive organs
-increases in thyroid cancer; relationship to other cancers
-increases

Pharm + Thera (6 decks)

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