Sympathomimetics

Question 1

Sympathomimetics as bronchodilators

Answer 1

B2 stimulants used to relieve bronchoconstriction in COPD

Receptors involved: B2, a1, B1(side effect)

Question 2

complications of COPD

Answer 2

emphysema- WBC proteolytic destruction of alveolar wall
asthma - allergic or intrinsic precipitated by cold, gas, paint
chronic bronchitis due to infection
bronchiecstasis - dilated bronchi b/c of infection

Question 3

True or False. Sympathetic bronchodilators can be used to diagnosis cause of airway obstruction.

Answer 3

True.

Obstruction may be due to inflammation or bronchiolar spasm

MOA: These drugs increase ciliary action and inhibit histamine, leukotriene (bronchoconstrictor) release

Question 4

Epinephrine acts on what adrenergic receptors

Answer 4

a1, B1, B2

Question 5

Albuterol acts on what adrenergic receptors

Answer 5

B2

Question 6

Metaproterenol acts on what adrenergic receptors

Answer 6

B2

Question 7

Salmeterol acts on what adrenergic receptors

Answer 7

B2; use in combination with steroids

mainly used for patients that wake up with asthmatic attacks (12 hr duration)

Question 8

Why are B2 agonist the drug of choice

Answer 8

most effective bronchodilators
tolerance can develop with continued use, but can be overcome with increased dosage
receptor down-regulation prevented by using corticosteroids

Question 9

Precautions for adrenergic bronchodilators

Answer 9

benign essential tremor due to B2 stimulation
feeling of anxiety
increased blood sugar (a1 and B2 mobilize liver glycogen)
dry pharyngeal membranes with epinephrine usage

Question 10

Nasal decongestants

Answer 10

a1 agonist constrict dilated vessels and relieve nasal stuffiness and headache

Drugs:
phenylephrine (best given orally)
pseudoephedrine (CNS stimulant)
oxymetazoline (12 hr duration)

Question 11

Adverse reactions to nasal decongestants

Answer 11

transient burning
rebound congestion
chemical rhinitis
CNS depression & hypotension with imidazoline usage

Question 12

Usage of sympathomimetics in the eye

Answer 12

mydriasis with phenylephrine –> advantage over atropine b/c no cycloplegia(loss of accommodation)

relieve redness and itching (oxymetazoline)

Question 13

Adrenergics in acute hypersensitivity

Answer 13

B2 stimulants inhibit antigen-induced histamine release

USE EPINEPHRINE

Question 14

Sympathomimetics used in hypotension

Answer 14

to be used you need below 40mmHg diastolic or 50 systolic

OR clinical situations showing decrease in BP (general and spinal anesthesia, drug overdoes, acute renal failure, shock)

Question 15

Two ways to increase blood pressure are

Answer 15

increase CO or increase peripheral resistance
(duration/CO/PR)
norepinephrine 2/0/increase
a1 stimulants (phenlyephrine) 20/dec/inc.
dopamine 2/inc/dec
dobutamine 2/inc/0

Question 16

Precautions of pressor agents

Answer 16

Hyperthyroidism

necrosis on prolonged vasoconstriction in liver and kidney

Question 17

Disease states showing adrenergic deficiency

Answer 17

pure autonomic failure (disease of postganglionic sympathetic nerves; mainly in men)
postural tachycardia syndrome (POTS) - common in females from viral illness
multiple system atrophy (MSA)- autoimmune degeneration ANS centrally; common in men

Question 18

Adrenergics in sympathetic deficiency

Answer 18

correct postural hypotension, urinary incontinence, and retrograde ejaculation

Tx: midodrine (a1 agonist) - give early in the day to avoid nocturnal hypertension

Question 19

Sympathomimetics as cardiac stimulants

Answer 19

In AV block to prevent loss of consciousness (Tx: pacemaker)
After bypass surgery
IV epinephrine, isoproterenol, dobutamine, dopamine

Question 20

Indirect-acting sympathomimetics

Answer 20

tyramine
dopamine
pseudoephedrine, ephedrine