3. • Antianginal are the pharmaceutical agents used to treat angina pectoris
Types of Antianginal drugs:
1. Nitrates
2. Calcium channel blockers
3. Beta adrenergic antagonists
4. Potassium channel opener
4. Nitrates
Classification:
1. Short acting- Glyceryl trinitrate( nitro-glycerine)
2. Long acting- Isosorbide dinitrate, Isosorbide mononitrate
Mechanism of action:
• Preload reduction:
dilates veins→ peripheral pooling of blood→ decreased venous
return.
• Redistribution of coronary flow:
relaxes the coronary arteries than arterioles
5. • Indications:
i. Angina pectoris
ii. Acute coronary syndrome
iii. Myocardial infarction
iv. CHF and acute left ventricular
failure
v. Cyanide poisoning
• Contraindications
i. Constrictive pericarditis
ii. Inferior myocardial infarction.
• Adverse effects
i. CNS: throbbing headache,
apprehension, restlessness, vertigo
ii. CVS: retrosternal discomfort,
orthostatic hypotension
iii. Dermatologic: exfoliative
dermatitis, pallor, perspiration
iv. GI: incontinence of urine and feces
6. • Glyceryl trinitrite:
Sublingual tablets are crushed under teeth and spread over buccal mucosa. It acts
within 1-2 mins
When angina is relieved, the drug should be spitted out or swallowed.
• Isosorbide dinitrite:
Last dose should not be taken later than 6 PM to allow nitrate level to fall during
sleep.
7. Calcium channel blockers
Classifications
Mechanism of action:
Negative inotropic effects
Inhibit the entry of calcium into cardiac and smooth muscle cells by blocking L-
type calcium channel, thus reducing peripheral resistance.
Dihydropyridines Nifedipine, nimodipine,
felodipine
Non-dihydropyridines Verapamil, diltiazem, bepridil
9. Β- adrenergic antagonists
Classification
Mechanism of action:
Blocks adrenergic receptors of sympathetic nervous system in the heart and kidney
Thus decreasing the excitability of heart and decreasing cardiac output and
decreasing release of renin
Non selective Propranolol, nadolol, timolol
Cardio selective Metoprolol, atenolol, esmolol
Partial agonists Pindolol, carteolol
Beta + alpha blocker Labetolol, carvidilol
10. Indications:
• Angina pectoris, hypertension
Contraindications:
• Sinus bradycardia, 2-3 degree heart block,
CHF
• COPD, cerebrovascular disease
Side effects
• Flatulance, constipation
• Development of antinuclear antibodies, AV
nodal block
Dose
Propranolol: 40-240mg
Metoprolol: 50-200mg
Pindolol: 10-45
11. Potassium channel opener
It opens ATP activated K+ channel in smooth muscles and causes hyperpolarization
and relaxation of vascular as well as visceral smooth muscle.
Decreases Ca2+ concentration within the cells
Examples:
• Nicorandil
• Pinacidil
