Post on 13-Jan-2016
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Antianginal DrugsGarrett J. Gross
Myocardial Preconditioning
• Single or multiple brief periods of ischemia result in a marked reduction in infarct size when the hearts are exposed to a more prolonged period of ischemia.
• Has 2 phases:Acute and Delayed PC• Acute phase lasts 1-2 Hours• Delayed phase lasts 24-72 Hours• Nitrogycerin(GTN) produces delayed PC in animal
and clinical studies.• This effect persists even in the presence of tolerance
to its vasodilator effects
" Decrease in the effect of a drugwhen administered in a long-acting form"
" Decrease in the effect of a drugwhen administered in a long-acting form"
NITRATESTOLERANCE
NITRATESTOLERANCE
Develops with all nitrates
Is dose-dependent
Disappears in 24 h. after stopping the drug
Tolerance can be avoided- Using the least effective dose- Creating discontinuous plasma levels
Develops with all nitrates
Is dose-dependent
Disappears in 24 h. after stopping the drug
Tolerance can be avoided- Using the least effective dose- Creating discontinuous plasma levels
NITRATES
CONTRAINDICATIONSNITRATES
CONTRAINDICATIONS
Previous hypersensitivity
Hypotension ( < 80 mmHg)
AMI with low ventricular filling pressure
1st trimester of pregnancy
Previous hypersensitivity
Hypotension ( < 80 mmHg)
AMI with low ventricular filling pressure
1st trimester of pregnancy
WITH CAUTION:WITH CAUTION:� Constrictive pericarditis� Intracranial hypertension� Hypertrophic cardiomyopathy
� Constrictive pericarditis� Intracranial hypertension� Hypertrophic cardiomyopathy
ß-ADRENERGIC BLOCKERSCONTRAINDICATIONS
ß-ADRENERGIC BLOCKERSCONTRAINDICATIONS
Hypotension: BP < 100 mmHg
Bradycardia: HR < 50 bpm
Chronic bronchitis, ASTHMA
Severe chronic renal insufficiency
Hypotension: BP < 100 mmHg
Bradycardia: HR < 50 bpm
Chronic bronchitis, ASTHMA
Severe chronic renal insufficiency
Reasons for Using Nitrates and Beta Blockers in Combination in Angina
• Beta Blockers prevent reflex tachycardia and contractility produced by nitrate-induced hypotension.
• Nitrates prevent any coronary vasospasm produced by Beta Blockers.
• Nitrates prevent increases in left ventricular filling pressure or preload resulting from the negative inotropic effects produced by Beta Blockers.
• Nitrates and Beta Blockers both reduce myocardial oxygen consumption by different mechanisms.
• Nitrates and Beta Blockers both increase subendocardial blood flow by different mechanisms