The Antianginals Cardiotonics

1
The AntianginalsCardiotonics Antihypertensives
RTH 245, Spring 2000
2
Antianginals

• Improve oxygen supply to the myocardium or
• Decrease myocardial oxygen demand or
• They do both of these

3
Antianginals

• The Nitrates
• Specific smooth muscle relaxants
• Form nitric oxide which stimulates guanyl
  cyclase, stimulating cGMP and therefore smooth
  muscle relaxation and vasodilation
• Examples Amyl nitrate nitroglycerine

4
Antianginals

• The Calcium Channel Blockers
• This decreases intracellular calcium and promotes
  vasodilation
• Examples Verapimil (Isoptin) and Cardizem

5
Antianginals

• The Beta Blockers
• These are negative inotropic, dromotropic and
  chronotropic agents
• Examples Non Selective Propanolol (Inderal)
• Examples Selective Metoprolol (Lopressor)

6
Cardiotonics

• Drugs that improve the force of cardiac
  contraction (inotropic agents)

7
Cardiotonics

• Cardiac glycosides (digitalis derivatives
• Deactivates the Na pump increasing intracellular
  Na and increase in Ca influx improving
  myocardial contractility
• As a result of vagal stimulation and decreased AV
  conduction, decreases in heart rates are well
  noted

8
Cardiotonics

• Cardiac glycosides
• Examples-- Digoxin and Digitoxin

9
Cardiotonics

• Catecholamines
• Improve cardiac efficiency through
• Direct DA1 (dopaminergic activity)
• a1 stimulation
• b1 stimulation
• Or
• Indirect stimulation of the release of
  norepinephrine

10
Cardiotonics

• Catecholamines
• Dopamine (Intropin) a quartenary amine
• Indirect stimulation of norepinephrine release
• Dobutamine (Dobutrex) derived from Isoproterenol
• Not to be used in cardiogenic shock
• Norepinephrine (Levophed) natural catecholamine
  (20 times more potent than dopamine
• Tx of choice in all forms of shock

11
Cardiotonics

• Cyclic AMP Phosphodiesterase Inhibitors
• By blocking phosphodiesterase, cAMP is increased
  in myocardial cells, increasing Ca influx
• This raises intracellular Ca
• Which improves myocardial contractility
• Examples Amrinone (Inocor)
• Milrinone (Primacor)

12
Antihypertensives

• These drugs lower blood pressure.
• Since blood pressure maintenance my be triggered
  by a medication lowering blood pressure, several
  drugs may be used to effectively lower BP.
• Even though the diuretic agents are important in
  antihypertensive Tx, they are not discussed here,
  since weve already covered them.

13
Antihypertensives

• Vasodilators--function to decrease preload and
  afterload by decreasing peripheral resistance
  through vasodilation.
• Some of these agents cause venous dilation as
  well (used in acute hypertensive crises, such as
  nitroprusside).

14
Antihypertensives

• Vasodilator Examples--
• Oral route--Hydralizine (Apresoline)
• Parenteral-- Nitroprusside(Nipride)
• Diazoxide (Hyperstat)

15
Antihypertensives

• Angiotensin Converting Enzyme Inhibitors
• The agents prevent the conversion of Angiotensin
  I to Angiotensin II by blocking Angiotensin
  Converting Enzyme
• Examples Captopril(Capoten)
• Enalipril (Vasotec)

16
Antihypertensives

• Sympatholytics -- function to block or inhibit
  the effects of the sympathetic nervous system,
  centrally or peripherally
• Central action agents--
• Methyldopa (Aldomet)
• Clonidine (Catapres)

17
Antihypertensives

• Sympatholytics (Peripheral Action, Beta Blockade)
• Propanolol (Inderal)
• Peripheral Action, Alpha Blockade)
• Prazosin (Minipres)

18
Antihypertensives

• Calcium Channel Blockers
• Such as Verapimil