Lec 07: Adrenergic Agents Flashcards
Drug of choice for the immediate treatment of anaphylactic shock.
Epinephrine
Type I, II, III or IV hypersensitivity reaction?
IgE-mediated acute allergic reactions to stings, pollens, and drugs, including anaphylaxis, urticaria, and angioedema.
Type I
Type I, II, III or IV hypersensitivity reaction?
Complement dependent allergic reactions.
Type II
Type I, II, III or IV hypersensitivity reaction?
Involve IgG or igM antibodies in which the antibody is fixed to circulating blood cell.
Type II
Type I, II, III or IV hypersensitivity reaction?
Serum sickness
Type III
Type I, II, III or IV hypersensitivity reaction?
Involves immune complexes containing IgG
Type III
Type I, II, III or IV hypersensitivity reaction?
Multisystem complement-dependent vasculitis
Type III
Type I, II, III or IV hypersensitivity reaction?
Cell-mediated allergy that is the mechanism involved in allergic contact dermatitis from topically applied drugs.
Type IV
Non-IgE-mediated reaction resulting from the direct release of mast cell mediators without stimulation.
Anaphylactoid Reaction
Identify the drug:
Immunosuppressive, blocks proliferation of IgE producing clones and inhibits IL-4 production by T-helper cells in the IgE response
Prednisone
Identify the drug:
Selective leukotriene receptor antagonist used for asthma
Montelukast
What are the effects of histamine on the Cardiovascular System?
- VASODILATION of arterioles and precapillary sphincters
- TACHYCARDIA
- EDEMA
- INCREASED CONTRACTILITY
- INCREASED PACEMAKER RATE
- End effect: Decreased systolic and diastolic BP due to peripheral vasodilation and increased heart rate
What are the effects of histamine on the GI Tract Smooth muscle?
- CONTRACTION -> Decreased Transit Time -> Can lead to Diarrhea
What are the effects of histamine on Bronchial Smooth Muscles?
BRONCHOCONSTRICTION -> Difficulty breathing
What is the Triple Response of Lewis?
FLUSH - (redness) can be due to direct vasodilatory effect of histamine
WHEAL - reflects histamine’s capacity to cause edema
FLARE - histamine-induced stimulation of axon reflexes, indirect vasodilation.
What is the physiologic antidote to histamine?
Epinephrine.
*Epinephrine reverses most of the effects of histamine (except for cardiac stimulation). It is a potent vasoconstrictor (B2 receptors in skeletal blood vessels & A1 receptors in vascular beds)
End effect: Increase in systolic blood pressure, decreased systolic blood pressure, increased heart rate.
CONTRAINDICATIONS of Epinephrine
Cardiac arrythmias
Angle glaucoma
Why is Epinephrine added to local anesthetics?
Added to local anesthetics (ex. Lidocaine) to
- decrease systemic absorptions (such as epinephrine-induced vasoconstriction -> decrease
transfer/absorption) - increase duration of action
- decrease toxicity of local anesthetics
TRUE or FALSE: If your patient is already being given dopamine IV, you CAN’T give epinephrine in the same IV line.
FALSE.
Yes you can. Other compatible hypotensives: dopamine, dobutamine at diltiazem (basta nagsstart sa ‘D’!)
Epinephrine is incompatible with aminophylline, sodium bicarbonate or other alkaline solutions.
After being taken up into adrenergic neuron, Epinephrine is degraded by:
Monoamine oxidase (MAO) and Catecholamine-o-methyl-transferase (COMT)
Correct dose for Epinephrine taken Intramuscularly (for anaphylaxis)
0.1-0.5mL of a 1:1000 solution.
Other dosage forms:
- Subcutaneous: 0.3-0.5 mL of 1:1000 solution
- Sublingual : 0.5mL; 1:1000 solution
- Femoral/IJV: 3-5mL of a 1:10,000 solution
- Endotracheal tube: 3-5mL of a 1:10,000 solution (solution diluted to 10 mL
with normal saline solution
diluted to 10 mL with normal saline through the endotracheal tube)
Best route for anaphylaxis treatment when patient has an IV line.
IV
Administering too much epinephrine may cause:
lesion necrosis
TRUE or FALSE:
Half doses of adrenaline may be safer for anaphylactic patients who are taking amitriptyline, imipramine or a beta blocker.
TRUE.
