HEENT Flashcards
(40 cards)
adrenergic receptor review
-4 major sympathetic receptors
-Alpha1
-Alpha2
-Beta1
-Beta2
-Response of organ depends on:
-Specificity of the agonist/antagonist at a given receptor
-The absolute number of receptors in that organ or organ system
-Ratio of receptors (which is prominent)
effects of stimulating adrenergic receptors
-Alpha1 – is the Primary receptor for HEENT indications
-Stimulation causes:
-Smooth muscle contraction
-Vasoconstriction (can help control blood flow)
-Decrease in mucous membrane secretion
-Beta1 – cardiac stimulation
-Beta2 – smooth muscle relaxation
sympathomimetics: hemorrhage
-Alpha1
-Epinephrine (Epi) - causes superficial vasoconstriction – controls capillary bleeding
-Ex: nasal surgery
-synergistic with lidocaine
symphatomimetics
- Adrenergic agonists
-Mixed acting - Combine w/ receptor and produce a response AND cause NE release or block it’s reuptake
-Ex: pseudoephedrine
-Ex: phenylpropanolamine (currently off the market)
-Alpha 1 agonist
-Ex: phenylephrine
-weak on beta activation -> not really heart symptoms but can increase
sympathomimetics: local anesthetics
-Alpha1
-Epi – causes local vasoconstriction – decrease s blood flow which slows absorption and localizes affect of anesthetic -> good for surgery
-synergetic with lidocaine
sympathomimetics: nasal decongestants
-Alpha agonists
-Applied locally or orally
-Constricts swollen (edematous) vessels/tissue
-Relieves mucosal congestion
sympathomimetics: anaphylaxis (acute allergic rxn)
-Epi:
-Alpha1 – relieves swelling
-Beta2 – relaxes constricted bronchial smooth muscle
-Beta1 – some cardiac stimulation – use with caution
sympathomimetics: hypotension
-hypotensive crisis
-alpha agonists:
-Increases blood pressure via vasoconstriction
-Caution:
-Ischemia in extremities, organs
-w/ prolonged administration
-Withdraw – taper off agent slowly to prevent recurrence
sympathomimetics for HEENT indications
-Nasal preparations
-Ophthalmic preparations
-Oral preparations
nasal preparations
-Topical – used as a vasoconstrictor
-1. Oxymetazolone (C) (afrin, dristan) – given BID (q12h!) -> spray and inhale at same time (adults)
-used for nasal surgery vasoconstriction
-dont use long term
-bloody nose, shaving cut
-2. Phenylephrine (C) (neo-synephrine) – given q4-6h -> more for kids
-Sprays
-Preferred in adults
-Better coverage of nasal mucosa
-Easier self administration
-Drops
-Preferred in children
-Nostrils are smaller – easily administered by adults
-Use lowest strength in children – not for <2yo
-Systemic absorption is minimal
-Slightly more w/ drops due to swallowing excess
nasal preparations: ADRs
-Local irritation (burning, stinging, sneezing, dryness)
-Rhinitis medicamentosa (rebound)!! -> comes back worse
-Do not use for > 3-4 days
-Receptor desensitization
-Contraindicated with MAO-Is
-Increase in heart rate
nasal preparations: rhinitis medicamentosa
-Can be caused by both oxymetazolone and phenylephrine
-Patient uses for >3-4 days, desensitization of receptors – does not get relief
-Starts with bid then tid then qid t-hen 5xd, 6xd, and so on
-Rebound can be worse than original congestion
ophthalmic preparation
-need to be more sterile
-itchy, red eyes
-Oxymetazolone (Ocuclear)
-Phenylephrine (Relief)
-Tetrahydrozaline (Visine)
-Naphazoline (Clear eyes, Naphcon)
ophthalmic preparations: cautions
-Contact lens – drops need to be compatible
-Narrow angle glaucoma – Contraindicated -> increase IOP
-Greater chance of systemic absorption with eye drops
-Due to relatively high concentration of medication contained in solution
-Drug absorbed directly into the tear duct
-To avoid / lessen the absorption, instruct patients to press on the tear duct when instilling the eye drop
systemic preparations: oral
-Related to amphetamine
-Examples:
-Pseudoephedrine (isomer of ephedrine) (sudafed) - better
-Ephedrine (Ma Huang)- Appetite suppressant
-Phenylpropanolamine (off the market)
-Excellent decongestant
-Used in appetite suppressants – i.e. dexatrim
-Phenylephrine - Also available as an injection -> not as good
systemic: oral preparations: single vs combo agents
-Available as single agents:
-Pseudoephedrine (Sudafed)
-Phenylephrine (Sudafed PE)
-And combo agents w/:
-Anti-histamine (with brompheniramine in Dimetapp)
-acetaminophen
-Ibuprofen
-Anti-tussive
** Combo of all of the above: “complete cold” formulas
-be careful over med overlaps -> overdose
systemic oral preparations: ADRs
-Binding to alpha receptors
-Systemic effects:
-Increased HR, BP, Palpitations
-Agitation - irritability
-Restlessness
-Insomnia
-Nervousness
-Appetite suppression
-Euphoria
-CNS stimulation – prominent aspect of amphetamines (indirect acting)
-Tolerance to stimulant properties – leading to drug dependence, esp. w/ amphetamines
antihistamines: histamine: where is it found
-Produced primarily by mast cells, basophils
-Abundant in skin, GI, resp tract
-GI – paracrine cells in fundus (lining) stimulates gastric secretion by parietal cells.
-CNS – neurotransmitter
-Formed by decarboxylation of histadine
-Released from mast cells by IgE (cromolyn NA blocks this action)
-Mast cell degranulation can be caused by: bacterial toxin, and drugs (morphine and tubocurarine) – get flushing, vasodilation when these are given
histamine: physiologic effects
-Primitive reflex, protective mechanism
-Vasodilation = decrease BP (relaxation of arteriolar smooth muscle and venules) = Hypotension
-Increase vasc permeability = edema (promotes fluid and plasma out of blood into extracellular spaces)
-Heart (tachycardia & increased contractility )- due to BP drop due to vasodilation
-Bronchoconstriction – in lungs (body trying to decrease the amount of allergens entering the lungs – protective)
antihistamines: histamine receptors
-H1, H2, H3
H1 receptor
-Mediates allergic rxns
-Dermatitis, rhinitis, conjunctivitis
-Activation in skin and mucous membranes causes vasodilation, increased vascular permeability, erythema, congestion, edema, inflammation
-Mucocutaneous nerves – pruritis, cough
-Histamine in circulation – decrease BP, anaphylactic shock
-ex. diphenhydramine
H2 receptor effects
-GI acid secretions – primarily
-Allergic rxns:
-H1 and H2 blockers may be used in combo for some allergic rxns (diphenhydramine + famotidine!)
-H2 receptors in heart:
-increase HR and increase contractility
antihistamines
-The H1 receptor antagonists block the actions of histamine by competitive inhibition at the receptor site.
-Most are capable of crossing the BBB and entering the CNS causing sedation.
-These antihistamines have many other effects NOT due to the histamine receptor.
-Their chemical structure is similar to other endogenous agents and so they are capable of combining with other receptors in the body to produce a variety of side effects.
-Some effects may be desirable (we can utilize their effect) and others undesirable
-H1 and H2 are synergistic
effects of antihistamines
-Treatment of allergic reactions, seasonal and allergic rhinitis
-Treatment of symptoms due to infections
-Treatment of motion sickness
-Anti-nausea & anti-emetic - central CTZ inhibition (phenothiazines)
-Treatment of insomnia (due to sedative side effects)
