HISTAMINE (autacoids)

histamine is produced by _____________________________

mast cells
basophils
parietal cells
CNS

name the precursor of histamine

histidine (H)

name the enzyme responsible for converting histidine to histamine

histidine decarboxylase

what histamine receptor is located in the:

• Vascular smooth muscles (blood vessels)

• Extravascular smooth muscles (e.g., bronchial smooth muscles)

• Sensory nerve endings (skin)

Histamine 1 receptor

what are the effects of h1 receptor in the ff locations:

Vascular smooth muscles (blood vessels): __________
Extravascular smooth muscles (e.g., bronchial smooth muscles): _________
Sensory nerve endings (skin): ____________

vasodilation
bronchoconstriction
itchiness/pruritis

what histamine receptor is located in the parietal cells (smooth)

H2 receptor

what histamine receptor is located in mast cells and basophils

H2 receptor

what are the effects of h2 receptor in the ff locations:

parietal cells (smooth): ___________

mast cells and basophils: ______________

increased HCl production (gastric acid)- peaks at night
increased histamine

what histamine receptor is located in the CNS

h3 receptor

what are the effects of h3 receptor:

inhibitory effect (decreased histamine)

what receptor has an effect of INCREASED HISTAMINE

h2 receptor

what receptor has an effect of DECREASED HISTAMINE

h3 receptor

what histamine receptor is located in neutrophils

h4 receptor

what are the effects of h4 receptor:

chemotaxis

a drug under histamine agonists that measures bronchial hyperactivity, and is also used for pulmonary challenge test

histamine

a drug under histamine agonists that determines adequacy of HCl secretion

histamine

a drug that is both a h1 agonist and h3 antagonist

betahistine (Serc)

a drug under histamine agonists that is used for management of vertigo and Meniere’s disease

betahistine (Serc)

is an accumulation of fluid in the endolymph (inner ear); aka Swimmer’s disease

Meniere’s disease

what are the 2 types of histamine antagonists:

Physiological / functional antagonism
Pharmacologic antagonism

a type of histamine antagonism in which consist of two drugs acting on different receptors

Physiological / functional antagonism

what type of histamine antagonism do histamine and adrenaline (epinephrine) belong to?

Physiological / functional antagonism

a type of histamine antagonism in which consist of two drugs acting on same receptors

Pharmacologic antagonism

what type of histamine antagonism do antihistamines belong to?

Pharmacologic antagonism

H1 antagonists or h1 blocker are (HYDROPHILIC / LIPOPHILIC)

lipophilic (can cross BBB)

h1 antagonist have (CENTRAL / PERIPHERAL) anticholinergic effects

central

other uses of h1 antagonists:
________________
________________
________________

sleeping aid
extrapyramidal symptoms
acute dystonic crisis

the generation of antihistamines that are known to be TRUE SEDATING

1st generation

name all chemical groups under 1st gen AH (EEPAPP)

ethanolamines
ethylenediamines
piperazines
alkylamines
phenothiazine
piperidine

drugs under this chemical group are the most sedating and the most effective of the 1st gen AH

ethanolamines

an ethanolamine that is used for management for dystonia

diphenhydramine (benadryl)

what generation and chemical group do the following AH belong to?

diphenhydramine (Benadryl®)
dimehydrinate
carbinoxamine
doxylamine

1st gen - ethanolamines

drugs under this chemical group are used for GI upset and have mild sedating effects

ethylenediamines

what generation and chemical group do the following AH belong to?

pyrilamine
tripelenamine

1st gen - ethylenediamines

drugs under this chemical group are either a prodrug or is used as treatment of motion sickness

piperazines

the drug under piperazine which is a prodrug and has its active constituent of: cetirizine

hydroxyzine (iterax)

the drug under piperazine that is used as treatment of motion sickness

meclizine (Bonamine)

what generation and chemical group do the following AH belong to?

meclizine (Bonamine®)
cyclizine
hydroxyzine (Iterax®)

1st gen - piperazines

drugs under this chemical group are components of cold medicines

alkylamines

what generation and chemical group do the following AH belong to?

chlorpheniramine
brompheniramine

1st gen - alkylamines

drugs under this chemical group are adjunct with anesthetics and increases pre-operative sedation

phenothiazine

the phenothiazine that is used as adjunct with anesthetics and increases pre-operative sedation

promethazine (phenergan)

what generation and chemical group do the following AH belong to?

promethazine (phenergan)

1st gen - phenothiazine

drugs under this chemical group are the DOC for serotonin syndrome (seizures, hyperthermia)

piperidine

the piperidine drug that is DOC for serotonin syndome (seizures, hyperthermia)

cyproheptadine

name the chemical groups under second generation AH

piperazine
piperidine

drugs under this chemical group are known to be less sedating

piperazine

what generation and chemical group do the following AH belong to?

cetirizine
levocetirizine

2nd gen - piperazine

drugs under this chemical group are known to be true non-sedating

piperidine

what generation and chemical group do the following AH belong to?

loratadine
desloratadine
fexofenadine,
terfenadine

2nd gen - piperidine

(H1 / H2) (AGONISTS / ANTAGONISTS) are used for hyperacidity

h2 antagonists

h2 antagonists is for treatment of ___________ disease

peptic ulcer disease (PID)

h2 antagonists are used in the management of acute ____________________ - to be taken at (MORNING / NIGHT)

acute GI ulcer bleeding

night

h2 antagonists are used as adjunct in treatment of _______ reactions

allergic reactions

the only h2 antagonist that can cause gynecomastia in males and hirsutism in females

cimetidine (H-bloc)

name all h2 antagonists (CFRN - HTZA)

cimetidine (H-bloc)
famotidine (Tagamet)
ranitidine (Zantac)
nizatidine (Axid)

the h2 antagonist that is the prototype, the least potent

cimetidine (H-bloc)

the h2 antagonist that is the most potent

famotidine (Tagamet)

the h2 antagonist that is the most bioavailable (has almost 100% oral bioavailability)

nizatidine (Axid)