HEENT Flashcards
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)
antihistamines: ADRs
-SEDATION
-Anticholinergic effects (blocks muscarinic receptor causing anti SLUDGE effects)
-Adrenergic blockade causing orthostatic hypotension (phenothiazines)
antihistamines for EENT indications: FIRST GENERATION
-Alkylamines:
-brompheniramine (Dimetapp) (B,D)
-chlorpheniramine (Chlortrimeton) (B,D)
-triprolidine (C) (in Histafed) - Cause the least amount of sedation (may even cause CNS stimulation)
-ethanolamonies:
-clemastine (Tavist)(B)
-diphenhydramine (Benadryl)(B) - VERY sedating, anticholinergic
-Piperazines:
-meclizine (Antivert)(B) – for dizziness, inner ear imbalances
-hydroxyzine (Vistaril, Atarax) - very sedating
-Phenothiazines:
-promethazine (Phenergan)(C) - very sedating, anticholinergic
-Piperidines:
-cyproheptadine (Periactin)(B) – used for GI effect – slowing peristalsis, anti-emetic
-better for urgent reactions- works quick
antihistamine: first generation ADRs
-Sedation most common ADR
-May get paradoxical excitation in children and infants
-Atropine-like ADRs (anti- SLUDGE) -> Dry mouth, blurred vision, tachycardia, urinary retention
-Anticholinergic toxicity – manifestation of overdose -> Administer physostigmine (cholinesterase inhibitor)
antihistamines: second generation
-Piperidines
-loratadine (Claritin) (B) - take a while to kick in, chronic use
-desloratadine (Clarinex) - 1o metabolite
-fexofenadine (Allegra) (C)
-Piperazines
-cetirizine (Zyrtec) (B)
-Levocetirizine (Xyzal) - isomer of cetirizine
***Brand name + D = has pseudoephedrine
-not good for urgent allergic reactions
-daily use
-not as drowsy
-same ADRs as first but without sedation
zyrtec and claritin eye drops
-Active ingredient is ketotifen (not cetirizine or loratadine) – it has antihistamine and mast cell stabilizing effects.
-Indicated for itchy eyes due to pollen, ragweed, grass animal hair and dander.
-To be further discussed in Ophthalmics lecture
2nd generation antihistamines
-The 2nd generations’ advantage over the first is that they are relatively specific for the H1 receptor and therefore have little or no sedative activity.
-HOWEVER, significant drug interactions with many antifungals (azoles) and most macrolides, causing lethal ventricular tachycardia (torsades de pointes) have already resulted in 2 drugs being removed from market. [astemizole (hismanal) and terfenadine (seldane)]
antihistamines: efficacy and kinetics
-Efficacy
-More effective in preventing histamine-mediated effects than reversing these effects
-Most effective when taken 1-2 hours prior to anticipated exposure of offending allergen
-Kinetics
-Well absorbed PO, large Vd, liver metabolism
cough and cold preparations in kids
April 2009: FDA updated the Public Health Advisory recommending that OTC cough and cold products not be used in infants and children less than 2 years. (Specifically referring to antihistamines, decongestants and dextromethorphan)
topical antihistamines
-Also considered 2nd generation - used for seasonal or allergic rhinitis
-levocabastine (Livostin) (C) - ophth drops
-azelastine (Astelin) (C) - nasal spray!!!! - works amazing
-olopatadine (Patanol) (C) - ophth drops mast cell stabilizer & antihistamine
-Ketotifen (Zatidor) (C) – ophth drops - mast cell stabilizer & antihistamine
miscellaneous: cromolyn
-stabilizes mast cell membranes and thereby preventing degranulation and release of histamine
-creates a film to stop it, doesnt actually stop it
-need to be used routinely
-(Crolom) (B) ophth drops
-(Nasalcrom) (B) nasal spray
miscellaneous: montelukast
-(Singulair) (PO) (B) BID
-Used for seasonal allergic rhinitis in adults & children over 2 years-old
-leukotriene receptor antagonist
-inhibits cyt P450 (coumadin, phenytoin)
-ADRs - headache, URI, nausea
-Will discuss further in asthma lecture
other agents for rhinitis
-Intranasal steroids:
-Very efficacious, also good if pt also has asthma
-Less systemic ADRs
-Slow onset to relieve symptoms (2-3 weeks)
-Ipratropium nasal spray (Atrovent-nasal)
-Saline nasal preps
miscellaneous: neomycin
-Otic (ear) antibiotics
-Neomycin containing preparations
-Neomycin, polymixin B & hydrocortisone (Cortisporin Otic Solution or Suspension)
-if there is a perforation -> use a suspension (less acidic than solution)
-Used for otitis externa
-Solution may be more irritating due to acid content
-Dose: 1-2 drop tid-qid. In severe infections – may give as often as q15-30 minutes and gradually reducing the frequency as the infection is controlled
miscellaneous: fluoroquinolones
-Otic (ear) antibiotics (fluoroquinolones) for otitis externa
-ciprofloxacin & hydrocortisone (Cipro HC suspension) - Dose: 3 drops bid (more convenient than cortisporin)
-ciprofloxacin & dexamethasone (Ciprodex susp)
-ofloxacin (Floxin Otic) & ciprofloxaicn (Cetraxal)- doesnt come with steroid
-these are suspensions
miscellaneous: carbamide peroxide
-ear preparation
-Carbamide Peroxide (Debrox)
-Used to emulsify and disperse ear wax.
-Dose: Tilt head sideways and instill 1 -10 drops (depending on age and patient size) in ear bid for up to 4 days. Must keep drops in ears for several minutes by keeping head tilted and placing cotton in ear.
miscellaneous: benzocaine
-(Hurricaine, Anbesol, Orajel, Cepacol, Kanka)
-oral prep and spray
-Local anesthetic
-Used topically for temporary relief of pain associated with pruritis, otitis externa, bee stings, insect bites, mouth and gum irritations, sunburn, hemorrhoids. Also used as an anesthetic lubricant for passage of catheters and endoscopic tubes
-May be combined with other anesthetics in different products such as Cetacaine
