farmakologi tht
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farmakologiTRANSCRIPT
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FARMAKOLOGI THT
dr.Sufi desrini M.Sc
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Nasal Congestion
Nasal congestion is one of the most frequent symptoms in URT disorders, such as allergic rhinitis, rhinosinusitis, nonallergic rhinitis, and nasal polyposis
Nasal congestion is also common symptom in otitis media and asthma
Mucosal inflammation is the central pathophysiological mechanism that contribute congestion,incl increased venous engorgement, increased nasal secretion and edema
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Nasal Congestion (cont)
Inflammation can reduce the physical sie of the nasal passages
Inducing vasodilatation, increasing BF and increasing vascular
permeability
Engorgement of nasal venous sinusoids,
swelling of inferior & anterior turbinates and
obs of nasal airflow
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Figure 1. Allergic sensitization
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Figure 2. Early Phase of allergi inflammation
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Figure 3. Late phase of allergic inflammation
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Figure 4. Allergic cascade of symptoms of allergic rhinitis
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Pharmacotherapy
H1-antihistamines
Intranasal Glucocorticoids
Decongestans
Chromones (Amnivisnaga)
Anticholinergics
Antileukotrienes
Allergen-Spesific Immunotherapy
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H-1 Antihistamines
inverse agonists
Antihistamines stabilise the inactive form and shift the equilibrium in the opposite direction.Thus, the amount of histamine-induced stimulationof a cell or tissue depends on the balance betweenhistamine and H1 antihistamines.
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H-1 Antihistamines(Cont1)
Common H1- receptor antagonists
First generation Second generation*
Hydroxyzine Cetirizine
Diphenhydramine Loratadine
Chlorpheniramine Desloratadine
Promethazine Fexofenadine
Levocetirizine
*Two earlier developed agents, astemizoleand terfenadine, werewithdrawn in 1986 because of cardiac toxicity adverse effects.
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H-
onset of effect occurs within 1-3 hours;
Duration of action varies from several hours to 24 hours,
First-generation antihistamines and some ofthe second-generation agents are oxidativelymetabolisedby the hepatic cytochromeP450 system,the exceptions being levocetirizine, cetirizine, and fexofenadine.
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Levocetirizineand cetirizineare excretedlargely unchanged in urine and fexofenadineis excretedmainly in the faecesbut also the urine
Concomitant administration of probenicidreduces the totalbody and renal clearance of fexofenadine
The bioavailability of fexofenadinemay be altered by simultaneousconsumption of grapefruit juice (reduced rateand absorption of the drug by almost 30%).
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bahan kuliah THT\daftar obat rhinitis alergi.docx
bahan kuliah THT/daftar obat rhinitis alergi.docx -
Nasal Decongestant
Nasal decongestants are vasoconstrictivedrugs extremely useful as nonprescription medication. Both oral and topical dosage forms are often chosen as therapy in the common cold.
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Mechanism of action:
Nasal decongestants belong to the pharmacological class of sympathomimeticamines. Decongestant stimulates alpha-adrenergic agonist, by constriction of blood vessels, reducing its supply to the nose, decrease the amount of blood in sinusoid vessels and decrease mucosal edema.
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Types of nasal decongestant:
Internally or systemic decongestant: (e.g. pseudoephedrine, phenylpropanolamine (PPA) and phenylephrine ).
Topical decongestant: drops or sprays (e.g. xylometazoline , phenylephrine , oxymetazoline , naphazoline).
Inhaler: (1 -desoxyephedrine and propylhexedrine ).
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Systemic nasal decongestant:
Mechanism of action:
Potent direct acting alpha -adrenergic stimulator with weak beta -Adrenergic activity, causes vasoconstriction of the arterioles of the nasal mucosa and conjunctive, activates the dilator muscle of the pupil to causes contraction, and produce systemic arterial vasoconstriction.
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Side effect of systemic decongestant:
CNS effect: Nervousness, restlessness, headach and insomnia.
CV effect: increase blood pressure and increase heart rate.
Urinary sphincter constriction
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Examples of systemic decongestant:
PseudoephedrinePhenylpropanolamine (PPA)phenylephrine
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PhenylephrineHCLPseudoephedrine
For Symptomatically relief of nasal and
nasopharyngeal mucosal congestion and relief of redness of the eye due
to irritation.
Its symptomatically relief of nasal congestion due to
common cold, upper respiratory allergies and it
promotes nasal or sinus drainage.
Indication
CNS: nervousness, irritability, restlessness, headache.
CV: 9blood pressure and heart rate is irregular and palpitation.
GIT : nausea, vomiting.
Neuromuscular and skeletal: weakness, tremor.
CNS: nervousness, irritability, restlessness, headache and insomnia.
CV: 9blood pressure and heart rate is irregular and palpitation.
GIT : nausea, vomiting.
Neuromuscular and skeletal:weakness, tremor.
Side effect