Beta adrenergic antagonists .pptx

8/13/2019 Beta adrenergic antagonists .pptx

1/15

Adrenergic blocking drugs

[Beta blockers]

Dr.Rathnakar U.P.MD.DIH.PGDHM16


2/15

Receptors - distribution

1

-Heart, JG cells in kidney

2 -Blood vessels, sk.muscles, eye.Bronchi

[Uterus, liver, GIT, GUT]

Blockade- beneficial effects and adverseeffects

15


3/15


4/15

13


5/15

Beta blockers

Beneficial effects

Antihypertensive

In myocardial ischemia

Antiarrhythmic

In CHF

Anxiety

Migraine

Glaucoma

ADEs

Bronchospasm

Blunts symptoms of

hypoglycemia and delaysrecovery

Muscle fatigue

12


6/15

Beta blockers

[Prototype-propranolol]

Antihypertensive

Only in hypertensive

1. C.O. [1]

2. renin release from JGA[1]3. Initially-TPR [2,

unopposed 1 in BV]

4. Long term- TPR???]

5. Reduced NA release[Presynaptic 2 blockade]

6. Central sympathetic outflow

Vasodilation [some blockers]

production of nitric oxide

blockade of 1 blockade of Ca2+entry

antioxidant activity

opening of K+channels

11


7/15


8/15

Beta blockers


MI

Acute-Limits infarct size

[Pt should not have HB, HRshould be more than 50]

Long term-Protects heart fromarrhythmias [VF and suddendeath]

Antiarrhythmic

Decrease ERP Decreases automaticity

Decreases AV conduction

Membrane stabilizing[LA]

K channel block [Sotalol]

Symp.overactivity

Acute- blockers worsen

Stable CHF- long termbenefits by reducing

1activity-

Reverseremodeling, improve

patient symptoms, preventhospitalization, and prolong life

CHF

[carvedilol, metoprolol, bisoprolol]

9


9/15

Beta blockers


Glaucoma

Reduces intraocular tension

by reducing aqueous humor

formation Timolol[non-selective],

beaxolol [1 selective]

Pheochromacytoma [after

blockade] Anxiety & tremors

Reduce symptoms

Inhibit peripheral conversion

of T4 [propranolol]

Hyperthyroidism & thyrotoxiccrisis

8


10/15

Beta blockers


Bronchospasm

Airway resistance least

affected in normal subjects In asthmatics & COPD

severe bronchospasm

Blunt recognition of

hypoglycemia

& delay recovery from

insulin-induced

hypoglycemia

Adverse serum lipid profile

Metabolic

7


11/15

Beta blockers


PK

Well absorbed

High First pass[Hepaticblood flow dependent]

Long term-reduces hepatic

blood flow BA more with food

Additive with digoxin &

verapamil-CI

Decongestants- BP

With antidiabetics

NSAIDs antihypertensive

effect

Lignocaine metabolism

BA of Chlorpromazine

Drug interactions

6


12/15

Beta blockers


ADEs

Worsen CHF in uncompensated

heart

Bradycardia

Worsens COPD

Delay recognition & recovery of

hypoglycemia

Exacerbates variant angina

Adverse lipid profile [cardio

selective & Pindolol safe]

Sudden withdrawal-

exacerbation of angina

Reduced ex.capacity

Worsening of PVD

Not related to beta blockade-

G.I.T, nightmares, insomnia, loss

of memory, sexual distress in

males

Practolol banned-

occulomucocutaneous

syndrome

ADEs

5


13/15

Beta blockers

[With special features]Cardioselective

[Metoprolol. Atenolol]

1 selective

Safe in COPD

Safe in diabetics

Less peripheral action on

BV[safe in pts with PVD]

Lipid profile not affected

Cannot suppress tremors

Less effect on ex.capacity

Less bradycardia at rest

Less withdrawal effect

[ continued agonistic action]

Not effective in

migraine[dilate cerebral

vessels]

Not in MI

Intrinsic sympathomimetic activity

[Pindolol]

4


14/15

Beta blockers

[With special features]

Lipid insoluble

[bisoprolol. Atenolol]

Less absorbed from GIT Undergo slower

metabolism-long duration

Do not cross BBB-insomnia

and nightmares lessWith K channel blockade

Sotalol

Better arrhythmic

activity???????

With blockade

Labetolol & Carvedilol [also

antioxidant]Ultra short acting

Esmolol [10 mts]

Membrane stabilizing

[Propranolol]

3


15/15

Clinical applications of blockers

Hypertension

Angina pectoris

MI

SVT

CHF

HCM

Migraine prophylaxis

Muscle tremors

Thyrotoxic crisis

Glaucoma 2

Beta adrenergic antagonists .pptx

Documents

Transcript of Beta adrenergic antagonists .pptx