Archive for the ‘ L4-Pharma HF ’ Category

L4- Pharmacology of Heart Failure

Covers Cardiac Glycosides, Antianginal Medications, and Peripheral Vasodilators.

Covers antiarrhythmics, beta blockers, and cardiac stimulants.

HEART FAILURE (HF)

Indication:

Manifestations:

  1. •DYSPNEA
  2. •ORTHOPNEA
  3. •TACHYCARDIA
  4. •URINE  VOLUME
  5. •EDEMA
  6. •NECK  VEINS
  7. •BASAL  LUNG CREPITATIONS

LINES  OF  TREATMENT:

•GENERAL  MEASURES •CAUSE

  1. •DIURETIC
  2. •VASODILATOR
  3. •INOTROPIC

Diuretics:

1.Loop Diuretics:

e.g.Furosemide

2. Antialdosterone

(Spironolacton) 

Vasodilators:

e.g. Converting Enzyme inhibitors

INOTROPICS

1•DA    &     DOBUTAMINE ( B1 agonists)

2•CARDIAC  GLYCOSIDES

Digoxin, digitoxin Aglycone ( steroid n. & lacton ring ) + sugar

PHARMACOKINETICS

Picture1

MECHANISM

I- Increasing Cytosolic free Ca+2

Picture2

II- Autonomic action:

a) Vagal

b) Sympathetic (only with toxic dose)

PH EFFECTS

(1- HEART)

Picture3

Mechanism of HR decrease:

Vagal:

1.Baroreceptor sens.

2.Central stim.

3.A-V conduction inh.

4.Pacemaker sens.

Extravagal:

1.Bainbridge R. abolish.

2.Cardiac compensation.

3.A-V conduction  direct inh.

CONDUCTION

ATRIUM  (Small ↑  – Large doses ↓  )

A.V. ↓ PYRKINJE FIBERS ↓

DIGITALIS  IS  BRADYCARDIC

EXCITABILITY

SMALL  DOSE ↑

LARGE  DOSE ↓

What  is   the condition in  CHF ?

AUTOMATICITY

DIGITALIS    IS    ARRHYTHMOGENIC  !!!  ???

HOW   ?

Mechanism of arrhythmogenecity:

1.Loss of intracellular K

2.A.P.  Shortening

3.Autonomic activity Picture4 Picture5

(2-BP)

Normalisation

(3-CORONARY Flow )

CONSTRICTION WITH  TOXIC DOSES

II  —-  KIDNEYS

DIURESIS

III —- GIT

VOMITING

IV —- CNS

EXCITABILITY  &  CONVULSIONS YELLOW VISION VOMITING

THERAPEUTIC  USES

INDICATIONS

ABSOLUTE  INDICATIONS

CHF Associated With AF & CHF in Children

RELATIVE  INDICATIONS

•DIURETIC  FAILURE

•AF

•A.  FLUTTER

•PAROXYSMAL  A.  TACHYCARDIA

CONTRAINDICATIONS

ABSOLUTE   CONTRAINDICATIONS

•HT.  BLOCK

•HYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY

•WOLF-PARKINSON  WHITE  S.

•PAROXYSMAL  V.  TACHYCARDIA

RELATIVE  CONTRAINDICATIONS

•OTHER CARDIAC  Disease

•CH. LUNG  Disease

•RENAL   Insufficiency

•HEPATIC Insufficiency

•HYPERTENSIVE  HT.F

•SICK SINUS  S.

•+  B.B.

•+  CARDIOVERSION

•HYPERSENSITIVE CAROTID  SINUS.

[1] DRUGS CLEARANCE ↓

1-Spironolactone

Monitor SDC & ↓ the dose

[2] DRUGS BIOAVAILABILITY ↓

1-Cholestyramine

2-Metoclopramide

Space  doses at  least  2h  apart

[3] DRUGS BIOAVAILABILITY ↑

1-Erythromycin  &  Tetracyclines

2-Propantheline

Monitor SDC & the dose

[4]   DIURETICS

Monitor  &  replace  K

Dosage  &  Administration  of   Cardiac Glycosides
DIGITALISATION

Establishement  &  Maintainance  of an Adequate  Concentration of  Digitalis in the  Heart

1-2 ng /ml  for digoxin & 10-15 ng /ml digitoxin

Achieved in   4-5   t1/2

(One  week for   digoxin  &  one  month  for digitoxin)

PREPARATIONS

•Digoxin:  tablets  0.25 mg  &  ampouls 0.25 mg/ml

•Digitoxin:  tablets  0.1  mg

I-    Rapid  DIGITALISATION
“ Cumulative  Method “

0.5 mg  * 2 /  day / 2 days

II-  RAPID  DIGITALISATION
“ Rapid  Loading  Method “

Loading  oral  dose  0.5 – 0.75  mg

Then

0.5 mg /  6 hrs

MAINTENANCE  DOSE

0.125  –  0.25  mg /d

ASSESSMENT  OF  RESPONSE

  1. •DYSPNEA
  2. •ORTHOPNEA
  3. •TACHYCARDIA
  4. •URINE  VOLUME
  5. •EDEMA
  6. •NECK  VEINS
  7. •BASAL  LUNG CREPITATIONS

PRECAUTIONS

•I.V.  Digitalisation  in  digitalised  patient

•Kalaemia

•Elderly people

DIGITALIS  TOXICITY

CARDIAC :

•A.V. Block

•Sinus Bradycardia

•P. & Non-P.  Atrial tachycardia

•V. extrasystoles

•V. tachycardia or fibrillation

EXTRACARDIAC :

•Vomiting

•Delirium

•Yellow vision, amblyopia, diplopia, scotomata

•Rash, gynaecomastia, galactorrhea

PREVENTION & MANAGEMENT

1st  with mild manifestations (visual & GIT) stop drug 1 or 2 days

2nd for dangerous arrhythmias:

•Stop Digitalis

•Stop Diuretics

•Correction of hypokalaemia

1•Antiarrhythmics:

Lignocaine or Phenytoin (In V. arrhythmias)

Atropine (In sinus bradycardia & A.V. block)

2•Digitalis antibodies ( Fab fragments of digitalis)

TREATMENT OF CARDIAC ASTHMA

•Hospitalisation

•Sitting with legs hanging

•The cause

•Morphine

•Oxygen

•Diuretic

•Vasodilator

•Rapid Digitalisation

•Aminophylline