11 - Adrenoreceptor blockers Flashcards Preview

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Flashcards in 11 - Adrenoreceptor blockers Deck (22)
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1
Q

Adrenoreceptor antagonist classification

A

a blockers

  • non selective
  • –irreversible (phenoxybenzamine)
  • –reversible (phentolamine)
  • a1 selective (prazosin)
  • a2 selective (yohimbine)

beta blockers

  • nonselective (propanolol)
  • b1 selective (atenolol)
  • b2 selective (butoxamine)
2
Q
PHENOXYBENZAMINE
class
similar drug
MOA
uses
SE
A
  • adrenergic antagonist a-nonselective
  • none
  • irrerversibly blocks a adrenergic receptors a1>a2
  • pheochromocytoma (presurgical)
  • orthostatic hypotension, reflex tachycardia, gi irritation, MI

forms covalent bonds with a receptors (effect lasts for several days)

3
Q
PHENTOLAMINE, TOLAZOLINE
class
similar drug
MOA
uses
SE
A
  • adrenergic antagonist a-nonselective
  • none
  • reversibly blocks a adrenergic receptors a1>a2
  • pheochromocytoma (presurgical), antidote to a1 agonist overdose, rebound hypertension
  • orthostatic hypotension, reflex tachycardia, gi irritation
4
Q
PRAZOSIN
class
similar drug
MOA
uses
SE
A
  • adrenergic antagonist a1 selective
  • doxazosin, terazosin, tamsulosin, sildosin, alfuzosin
  • selectively blocks a1 adrenergic receptors
  • BPH, hypertension
  • first dose orthostatic hypotension, reflex tachycardia (less chance)

tamsulosin is most selective for prostatic smooth muscle

5
Q

What is the pharmacologic advantage of a1 selectivity?

A

reflex tachycardia is less common and less severe

6
Q

isoproerenorol is NOT a beta blocker. it is a:

A

non-selective beta agonist

7
Q
PROPANOLOL
class
similar drug
MOA
uses
SE
A
  • adrenergic antagonist b nonselective
  • pindolol, timolol, labetalol, carvedilol, nadolol, levobunolol, metipranolol
  • blocks b1 and b2 receptors. blocks sympathetic effects on heart and BP, reduces renin release
  • angina prophylaxis, hypertension, arrhythmias, migraine, performance anxiety, hyperthyroidism
  • bronchospasm, av block, heart failure, cns sedation, erectile dysfunction

masks symptoms of hypoglycemia in diabetics
carvedilol and labetalol has combined a and b blockade (may be used for pheochromocytoma)

8
Q

beta blockers in diabetic patients

A
  • masking of premonitory symptoms of hypoglycemia from insulin overdosage (tachycardia, tremor, anxiety)
  • impaired hepatic mobilization of glucose
9
Q

intrinsic sympathomimetic activity

A
  • partial agonist activity
  • advantage in treating patients with asthma because these drugs are less likely to cause bronchospasm
  • acebutolol, pindolol, carteolol, bopindolol, oxprenolol, celiprolol, penbutolol
10
Q

beta blockers with intrinsic sympathomimetic activity

A

pindolol, acebutolol

11
Q

local anesthetic activity

A
  • membrane stabilizing activity
  • disadvantage when beta blockers are used topically in the eye
  • – decreases protective reflexes
  • – increases the risk of corneal ulceration
  • absent from timolol and betaxolol making them useful for glaucoma
12
Q

non selective beta blocker with longest half-life

A

nadolol

13
Q
ATENOLOL
class
similar drug
MOA
uses
SE
A
  • adrenergic antagonist b1 selective
  • betaxolol, esmolol, acebutolol, metoprolol, alprenolol, nebivolol
  • selectively blocks b1 receptors, blocks sympathetic effects on heart and BP
  • angina, hypertension, heart failure, SVT (esmolol only)
  • bronchospasm (less chance), av block, heart failure, cns sedation, erectile dysfunction

masks symptoms of hypoglycemia in diabetics

14
Q

selective beta blocker with shortest half-life

A

esmolol

15
Q

flow of acqueous humor

A
ciliary body
posterior chamber
anterior chamber angle
pupil
anterior chamber
trabecular meshwork
canal of schlemm
uveoscleral veins
16
Q

Treatment of glaucoma:

beta blocker

A

timolol

decreased secretion of aqueous humor from the ciliary epithelium

17
Q

Treatment of glaucoma:

osmotic agents

A

mannitol

decreased secretion of aqueous humor from the ciliary epithelium

18
Q

Treatment of glaucoma:

a2 agonist

A

apraclonidine

decreased secretion of aqueous humor from the ciliary epithelium

19
Q

Treatment of glaucoma:

carbonic anhydrase inhibitors

A

acetazolamide
dorzolamide
decreased secretion of aqueous humor from the ciliary epithelium

20
Q

Treatment of glaucoma:

cholinomimetics

A

pilocarpine
physostigmine
ciliary muscle contraction, opening of trabecular meshwork, increased outflow

21
Q

Treatment of glaucoma:

prostaglandins

A

latanoprost

increased outflow through canal of schlemm

22
Q

Treatment of glaucoma:

non selective a agonist

A

epinephrine

increased outflow via uveoscleral veins